3489 lines
92 KiB
C
3489 lines
92 KiB
C
/*
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* Copyright (C) 1991, 1992 Linus Torvalds
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* Copyright (C) 1994, Karl Keyte: Added support for disk statistics
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* Elevator latency, (C) 2000 Andrea Arcangeli <andrea@suse.de> SuSE
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* Queue request tables / lock, selectable elevator, Jens Axboe <axboe@suse.de>
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* kernel-doc documentation started by NeilBrown <neilb@cse.unsw.edu.au>
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* - July2000
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* bio rewrite, highmem i/o, etc, Jens Axboe <axboe@suse.de> - may 2001
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*/
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/*
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* This handles all read/write requests to block devices
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*/
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/backing-dev.h>
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#include <linux/bio.h>
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#include <linux/blkdev.h>
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#include <linux/blk-mq.h>
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#include <linux/highmem.h>
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#include <linux/mm.h>
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#include <linux/kernel_stat.h>
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#include <linux/string.h>
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#include <linux/init.h>
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#include <linux/completion.h>
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#include <linux/slab.h>
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#include <linux/swap.h>
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#include <linux/writeback.h>
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#include <linux/task_io_accounting_ops.h>
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#include <linux/fault-inject.h>
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#include <linux/list_sort.h>
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#include <linux/delay.h>
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#include <linux/ratelimit.h>
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#include <linux/pm_runtime.h>
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#include <linux/blk-cgroup.h>
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#define CREATE_TRACE_POINTS
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#include <trace/events/block.h>
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#include "blk.h"
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#include "blk-mq.h"
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#include "blk-mq-sched.h"
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#include "blk-wbt.h"
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EXPORT_TRACEPOINT_SYMBOL_GPL(block_bio_remap);
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EXPORT_TRACEPOINT_SYMBOL_GPL(block_rq_remap);
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EXPORT_TRACEPOINT_SYMBOL_GPL(block_bio_complete);
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EXPORT_TRACEPOINT_SYMBOL_GPL(block_split);
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EXPORT_TRACEPOINT_SYMBOL_GPL(block_unplug);
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DEFINE_IDA(blk_queue_ida);
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/*
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* For the allocated request tables
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*/
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struct kmem_cache *request_cachep;
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/*
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* For queue allocation
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*/
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struct kmem_cache *blk_requestq_cachep;
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/*
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* Controlling structure to kblockd
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*/
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static struct workqueue_struct *kblockd_workqueue;
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static void blk_clear_congested(struct request_list *rl, int sync)
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{
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#ifdef CONFIG_CGROUP_WRITEBACK
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clear_wb_congested(rl->blkg->wb_congested, sync);
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#else
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/*
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* If !CGROUP_WRITEBACK, all blkg's map to bdi->wb and we shouldn't
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* flip its congestion state for events on other blkcgs.
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*/
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if (rl == &rl->q->root_rl)
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clear_wb_congested(rl->q->backing_dev_info.wb.congested, sync);
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#endif
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}
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static void blk_set_congested(struct request_list *rl, int sync)
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{
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#ifdef CONFIG_CGROUP_WRITEBACK
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set_wb_congested(rl->blkg->wb_congested, sync);
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#else
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/* see blk_clear_congested() */
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if (rl == &rl->q->root_rl)
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set_wb_congested(rl->q->backing_dev_info.wb.congested, sync);
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#endif
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}
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void blk_queue_congestion_threshold(struct request_queue *q)
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{
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int nr;
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nr = q->nr_requests - (q->nr_requests / 8) + 1;
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if (nr > q->nr_requests)
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nr = q->nr_requests;
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q->nr_congestion_on = nr;
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nr = q->nr_requests - (q->nr_requests / 8) - (q->nr_requests / 16) - 1;
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if (nr < 1)
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nr = 1;
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q->nr_congestion_off = nr;
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}
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/**
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* blk_get_backing_dev_info - get the address of a queue's backing_dev_info
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* @bdev: device
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*
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* Locates the passed device's request queue and returns the address of its
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* backing_dev_info. This function can only be called if @bdev is opened
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* and the return value is never NULL.
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*/
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struct backing_dev_info *blk_get_backing_dev_info(struct block_device *bdev)
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{
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struct request_queue *q = bdev_get_queue(bdev);
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return &q->backing_dev_info;
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}
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EXPORT_SYMBOL(blk_get_backing_dev_info);
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void blk_rq_init(struct request_queue *q, struct request *rq)
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{
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memset(rq, 0, sizeof(*rq));
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INIT_LIST_HEAD(&rq->queuelist);
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INIT_LIST_HEAD(&rq->timeout_list);
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rq->cpu = -1;
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rq->q = q;
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rq->__sector = (sector_t) -1;
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INIT_HLIST_NODE(&rq->hash);
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RB_CLEAR_NODE(&rq->rb_node);
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rq->cmd = rq->__cmd;
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rq->cmd_len = BLK_MAX_CDB;
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rq->tag = -1;
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rq->internal_tag = -1;
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rq->start_time = jiffies;
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set_start_time_ns(rq);
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rq->part = NULL;
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}
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EXPORT_SYMBOL(blk_rq_init);
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static void req_bio_endio(struct request *rq, struct bio *bio,
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unsigned int nbytes, int error)
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{
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if (error)
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bio->bi_error = error;
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if (unlikely(rq->rq_flags & RQF_QUIET))
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bio_set_flag(bio, BIO_QUIET);
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bio_advance(bio, nbytes);
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/* don't actually finish bio if it's part of flush sequence */
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if (bio->bi_iter.bi_size == 0 && !(rq->rq_flags & RQF_FLUSH_SEQ))
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bio_endio(bio);
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}
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void blk_dump_rq_flags(struct request *rq, char *msg)
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{
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int bit;
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printk(KERN_INFO "%s: dev %s: type=%x, flags=%llx\n", msg,
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rq->rq_disk ? rq->rq_disk->disk_name : "?", rq->cmd_type,
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(unsigned long long) rq->cmd_flags);
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printk(KERN_INFO " sector %llu, nr/cnr %u/%u\n",
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(unsigned long long)blk_rq_pos(rq),
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blk_rq_sectors(rq), blk_rq_cur_sectors(rq));
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printk(KERN_INFO " bio %p, biotail %p, len %u\n",
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rq->bio, rq->biotail, blk_rq_bytes(rq));
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if (rq->cmd_type == REQ_TYPE_BLOCK_PC) {
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printk(KERN_INFO " cdb: ");
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for (bit = 0; bit < BLK_MAX_CDB; bit++)
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printk("%02x ", rq->cmd[bit]);
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printk("\n");
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}
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}
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EXPORT_SYMBOL(blk_dump_rq_flags);
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static void blk_delay_work(struct work_struct *work)
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{
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struct request_queue *q;
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q = container_of(work, struct request_queue, delay_work.work);
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spin_lock_irq(q->queue_lock);
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__blk_run_queue(q);
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spin_unlock_irq(q->queue_lock);
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}
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/**
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* blk_delay_queue - restart queueing after defined interval
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* @q: The &struct request_queue in question
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* @msecs: Delay in msecs
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*
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* Description:
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* Sometimes queueing needs to be postponed for a little while, to allow
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* resources to come back. This function will make sure that queueing is
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* restarted around the specified time. Queue lock must be held.
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*/
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void blk_delay_queue(struct request_queue *q, unsigned long msecs)
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{
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if (likely(!blk_queue_dead(q)))
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queue_delayed_work(kblockd_workqueue, &q->delay_work,
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msecs_to_jiffies(msecs));
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}
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EXPORT_SYMBOL(blk_delay_queue);
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/**
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* blk_start_queue_async - asynchronously restart a previously stopped queue
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* @q: The &struct request_queue in question
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*
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* Description:
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* blk_start_queue_async() will clear the stop flag on the queue, and
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* ensure that the request_fn for the queue is run from an async
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* context.
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**/
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void blk_start_queue_async(struct request_queue *q)
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{
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queue_flag_clear(QUEUE_FLAG_STOPPED, q);
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blk_run_queue_async(q);
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}
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EXPORT_SYMBOL(blk_start_queue_async);
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/**
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* blk_start_queue - restart a previously stopped queue
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* @q: The &struct request_queue in question
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*
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* Description:
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* blk_start_queue() will clear the stop flag on the queue, and call
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* the request_fn for the queue if it was in a stopped state when
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* entered. Also see blk_stop_queue(). Queue lock must be held.
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**/
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void blk_start_queue(struct request_queue *q)
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{
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WARN_ON(!irqs_disabled());
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queue_flag_clear(QUEUE_FLAG_STOPPED, q);
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__blk_run_queue(q);
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}
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EXPORT_SYMBOL(blk_start_queue);
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/**
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* blk_stop_queue - stop a queue
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* @q: The &struct request_queue in question
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*
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* Description:
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* The Linux block layer assumes that a block driver will consume all
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* entries on the request queue when the request_fn strategy is called.
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* Often this will not happen, because of hardware limitations (queue
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* depth settings). If a device driver gets a 'queue full' response,
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* or if it simply chooses not to queue more I/O at one point, it can
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* call this function to prevent the request_fn from being called until
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* the driver has signalled it's ready to go again. This happens by calling
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* blk_start_queue() to restart queue operations. Queue lock must be held.
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**/
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void blk_stop_queue(struct request_queue *q)
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{
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cancel_delayed_work(&q->delay_work);
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queue_flag_set(QUEUE_FLAG_STOPPED, q);
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}
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EXPORT_SYMBOL(blk_stop_queue);
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/**
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* blk_sync_queue - cancel any pending callbacks on a queue
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* @q: the queue
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*
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* Description:
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* The block layer may perform asynchronous callback activity
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* on a queue, such as calling the unplug function after a timeout.
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* A block device may call blk_sync_queue to ensure that any
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* such activity is cancelled, thus allowing it to release resources
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* that the callbacks might use. The caller must already have made sure
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* that its ->make_request_fn will not re-add plugging prior to calling
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* this function.
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*
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* This function does not cancel any asynchronous activity arising
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* out of elevator or throttling code. That would require elevator_exit()
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* and blkcg_exit_queue() to be called with queue lock initialized.
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*
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*/
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void blk_sync_queue(struct request_queue *q)
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{
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del_timer_sync(&q->timeout);
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if (q->mq_ops) {
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struct blk_mq_hw_ctx *hctx;
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int i;
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queue_for_each_hw_ctx(q, hctx, i) {
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cancel_work_sync(&hctx->run_work);
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cancel_delayed_work_sync(&hctx->delay_work);
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}
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} else {
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cancel_delayed_work_sync(&q->delay_work);
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}
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}
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EXPORT_SYMBOL(blk_sync_queue);
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/**
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* __blk_run_queue_uncond - run a queue whether or not it has been stopped
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* @q: The queue to run
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*
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* Description:
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* Invoke request handling on a queue if there are any pending requests.
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* May be used to restart request handling after a request has completed.
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* This variant runs the queue whether or not the queue has been
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* stopped. Must be called with the queue lock held and interrupts
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* disabled. See also @blk_run_queue.
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*/
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inline void __blk_run_queue_uncond(struct request_queue *q)
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{
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if (unlikely(blk_queue_dead(q)))
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return;
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/*
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* Some request_fn implementations, e.g. scsi_request_fn(), unlock
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* the queue lock internally. As a result multiple threads may be
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* running such a request function concurrently. Keep track of the
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* number of active request_fn invocations such that blk_drain_queue()
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* can wait until all these request_fn calls have finished.
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*/
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q->request_fn_active++;
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q->request_fn(q);
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q->request_fn_active--;
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}
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EXPORT_SYMBOL_GPL(__blk_run_queue_uncond);
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/**
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* __blk_run_queue - run a single device queue
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* @q: The queue to run
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*
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* Description:
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* See @blk_run_queue. This variant must be called with the queue lock
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* held and interrupts disabled.
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*/
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void __blk_run_queue(struct request_queue *q)
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{
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if (unlikely(blk_queue_stopped(q)))
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return;
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__blk_run_queue_uncond(q);
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}
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EXPORT_SYMBOL(__blk_run_queue);
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/**
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* blk_run_queue_async - run a single device queue in workqueue context
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* @q: The queue to run
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*
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* Description:
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* Tells kblockd to perform the equivalent of @blk_run_queue on behalf
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* of us. The caller must hold the queue lock.
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*/
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void blk_run_queue_async(struct request_queue *q)
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{
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if (likely(!blk_queue_stopped(q) && !blk_queue_dead(q)))
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mod_delayed_work(kblockd_workqueue, &q->delay_work, 0);
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}
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EXPORT_SYMBOL(blk_run_queue_async);
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/**
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* blk_run_queue - run a single device queue
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* @q: The queue to run
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*
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* Description:
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* Invoke request handling on this queue, if it has pending work to do.
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* May be used to restart queueing when a request has completed.
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*/
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void blk_run_queue(struct request_queue *q)
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{
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unsigned long flags;
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spin_lock_irqsave(q->queue_lock, flags);
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__blk_run_queue(q);
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spin_unlock_irqrestore(q->queue_lock, flags);
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}
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EXPORT_SYMBOL(blk_run_queue);
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void blk_put_queue(struct request_queue *q)
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{
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kobject_put(&q->kobj);
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}
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EXPORT_SYMBOL(blk_put_queue);
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/**
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* __blk_drain_queue - drain requests from request_queue
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* @q: queue to drain
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* @drain_all: whether to drain all requests or only the ones w/ ELVPRIV
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*
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* Drain requests from @q. If @drain_all is set, all requests are drained.
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* If not, only ELVPRIV requests are drained. The caller is responsible
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* for ensuring that no new requests which need to be drained are queued.
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*/
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static void __blk_drain_queue(struct request_queue *q, bool drain_all)
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__releases(q->queue_lock)
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__acquires(q->queue_lock)
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{
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int i;
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lockdep_assert_held(q->queue_lock);
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while (true) {
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bool drain = false;
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/*
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* The caller might be trying to drain @q before its
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* elevator is initialized.
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*/
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if (q->elevator)
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elv_drain_elevator(q);
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blkcg_drain_queue(q);
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/*
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* This function might be called on a queue which failed
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* driver init after queue creation or is not yet fully
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* active yet. Some drivers (e.g. fd and loop) get unhappy
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* in such cases. Kick queue iff dispatch queue has
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* something on it and @q has request_fn set.
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*/
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if (!list_empty(&q->queue_head) && q->request_fn)
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__blk_run_queue(q);
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drain |= q->nr_rqs_elvpriv;
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drain |= q->request_fn_active;
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/*
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* Unfortunately, requests are queued at and tracked from
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* multiple places and there's no single counter which can
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* be drained. Check all the queues and counters.
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*/
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if (drain_all) {
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struct blk_flush_queue *fq = blk_get_flush_queue(q, NULL);
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drain |= !list_empty(&q->queue_head);
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for (i = 0; i < 2; i++) {
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drain |= q->nr_rqs[i];
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drain |= q->in_flight[i];
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if (fq)
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drain |= !list_empty(&fq->flush_queue[i]);
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}
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}
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if (!drain)
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break;
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spin_unlock_irq(q->queue_lock);
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msleep(10);
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spin_lock_irq(q->queue_lock);
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}
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/*
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* With queue marked dead, any woken up waiter will fail the
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* allocation path, so the wakeup chaining is lost and we're
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* left with hung waiters. We need to wake up those waiters.
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*/
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if (q->request_fn) {
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struct request_list *rl;
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blk_queue_for_each_rl(rl, q)
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for (i = 0; i < ARRAY_SIZE(rl->wait); i++)
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wake_up_all(&rl->wait[i]);
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}
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}
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/**
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* blk_queue_bypass_start - enter queue bypass mode
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* @q: queue of interest
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*
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* In bypass mode, only the dispatch FIFO queue of @q is used. This
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* function makes @q enter bypass mode and drains all requests which were
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* throttled or issued before. On return, it's guaranteed that no request
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* is being throttled or has ELVPRIV set and blk_queue_bypass() %true
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* inside queue or RCU read lock.
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*/
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void blk_queue_bypass_start(struct request_queue *q)
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{
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spin_lock_irq(q->queue_lock);
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q->bypass_depth++;
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queue_flag_set(QUEUE_FLAG_BYPASS, q);
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spin_unlock_irq(q->queue_lock);
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/*
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* Queues start drained. Skip actual draining till init is
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* complete. This avoids lenghty delays during queue init which
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* can happen many times during boot.
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*/
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if (blk_queue_init_done(q)) {
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spin_lock_irq(q->queue_lock);
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__blk_drain_queue(q, false);
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spin_unlock_irq(q->queue_lock);
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/* ensure blk_queue_bypass() is %true inside RCU read lock */
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synchronize_rcu();
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}
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}
|
|
EXPORT_SYMBOL_GPL(blk_queue_bypass_start);
|
|
|
|
/**
|
|
* blk_queue_bypass_end - leave queue bypass mode
|
|
* @q: queue of interest
|
|
*
|
|
* Leave bypass mode and restore the normal queueing behavior.
|
|
*/
|
|
void blk_queue_bypass_end(struct request_queue *q)
|
|
{
|
|
spin_lock_irq(q->queue_lock);
|
|
if (!--q->bypass_depth)
|
|
queue_flag_clear(QUEUE_FLAG_BYPASS, q);
|
|
WARN_ON_ONCE(q->bypass_depth < 0);
|
|
spin_unlock_irq(q->queue_lock);
|
|
}
|
|
EXPORT_SYMBOL_GPL(blk_queue_bypass_end);
|
|
|
|
void blk_set_queue_dying(struct request_queue *q)
|
|
{
|
|
spin_lock_irq(q->queue_lock);
|
|
queue_flag_set(QUEUE_FLAG_DYING, q);
|
|
spin_unlock_irq(q->queue_lock);
|
|
|
|
if (q->mq_ops)
|
|
blk_mq_wake_waiters(q);
|
|
else {
|
|
struct request_list *rl;
|
|
|
|
spin_lock_irq(q->queue_lock);
|
|
blk_queue_for_each_rl(rl, q) {
|
|
if (rl->rq_pool) {
|
|
wake_up(&rl->wait[BLK_RW_SYNC]);
|
|
wake_up(&rl->wait[BLK_RW_ASYNC]);
|
|
}
|
|
}
|
|
spin_unlock_irq(q->queue_lock);
|
|
}
|
|
}
|
|
EXPORT_SYMBOL_GPL(blk_set_queue_dying);
|
|
|
|
/**
|
|
* blk_cleanup_queue - shutdown a request queue
|
|
* @q: request queue to shutdown
|
|
*
|
|
* Mark @q DYING, drain all pending requests, mark @q DEAD, destroy and
|
|
* put it. All future requests will be failed immediately with -ENODEV.
|
|
*/
|
|
void blk_cleanup_queue(struct request_queue *q)
|
|
{
|
|
spinlock_t *lock = q->queue_lock;
|
|
|
|
/* mark @q DYING, no new request or merges will be allowed afterwards */
|
|
mutex_lock(&q->sysfs_lock);
|
|
blk_set_queue_dying(q);
|
|
spin_lock_irq(lock);
|
|
|
|
/*
|
|
* A dying queue is permanently in bypass mode till released. Note
|
|
* that, unlike blk_queue_bypass_start(), we aren't performing
|
|
* synchronize_rcu() after entering bypass mode to avoid the delay
|
|
* as some drivers create and destroy a lot of queues while
|
|
* probing. This is still safe because blk_release_queue() will be
|
|
* called only after the queue refcnt drops to zero and nothing,
|
|
* RCU or not, would be traversing the queue by then.
|
|
*/
|
|
q->bypass_depth++;
|
|
queue_flag_set(QUEUE_FLAG_BYPASS, q);
|
|
|
|
queue_flag_set(QUEUE_FLAG_NOMERGES, q);
|
|
queue_flag_set(QUEUE_FLAG_NOXMERGES, q);
|
|
queue_flag_set(QUEUE_FLAG_DYING, q);
|
|
spin_unlock_irq(lock);
|
|
mutex_unlock(&q->sysfs_lock);
|
|
|
|
/*
|
|
* Drain all requests queued before DYING marking. Set DEAD flag to
|
|
* prevent that q->request_fn() gets invoked after draining finished.
|
|
*/
|
|
blk_freeze_queue(q);
|
|
spin_lock_irq(lock);
|
|
if (!q->mq_ops)
|
|
__blk_drain_queue(q, true);
|
|
queue_flag_set(QUEUE_FLAG_DEAD, q);
|
|
spin_unlock_irq(lock);
|
|
|
|
/* for synchronous bio-based driver finish in-flight integrity i/o */
|
|
blk_flush_integrity();
|
|
|
|
/* @q won't process any more request, flush async actions */
|
|
del_timer_sync(&q->backing_dev_info.laptop_mode_wb_timer);
|
|
blk_sync_queue(q);
|
|
|
|
if (q->mq_ops)
|
|
blk_mq_free_queue(q);
|
|
percpu_ref_exit(&q->q_usage_counter);
|
|
|
|
spin_lock_irq(lock);
|
|
if (q->queue_lock != &q->__queue_lock)
|
|
q->queue_lock = &q->__queue_lock;
|
|
spin_unlock_irq(lock);
|
|
|
|
bdi_unregister(&q->backing_dev_info);
|
|
|
|
/* @q is and will stay empty, shutdown and put */
|
|
blk_put_queue(q);
|
|
}
|
|
EXPORT_SYMBOL(blk_cleanup_queue);
|
|
|
|
/* Allocate memory local to the request queue */
|
|
static void *alloc_request_struct(gfp_t gfp_mask, void *data)
|
|
{
|
|
int nid = (int)(long)data;
|
|
return kmem_cache_alloc_node(request_cachep, gfp_mask, nid);
|
|
}
|
|
|
|
static void free_request_struct(void *element, void *unused)
|
|
{
|
|
kmem_cache_free(request_cachep, element);
|
|
}
|
|
|
|
int blk_init_rl(struct request_list *rl, struct request_queue *q,
|
|
gfp_t gfp_mask)
|
|
{
|
|
if (unlikely(rl->rq_pool))
|
|
return 0;
|
|
|
|
rl->q = q;
|
|
rl->count[BLK_RW_SYNC] = rl->count[BLK_RW_ASYNC] = 0;
|
|
rl->starved[BLK_RW_SYNC] = rl->starved[BLK_RW_ASYNC] = 0;
|
|
init_waitqueue_head(&rl->wait[BLK_RW_SYNC]);
|
|
init_waitqueue_head(&rl->wait[BLK_RW_ASYNC]);
|
|
|
|
rl->rq_pool = mempool_create_node(BLKDEV_MIN_RQ, alloc_request_struct,
|
|
free_request_struct,
|
|
(void *)(long)q->node, gfp_mask,
|
|
q->node);
|
|
if (!rl->rq_pool)
|
|
return -ENOMEM;
|
|
|
|
return 0;
|
|
}
|
|
|
|
void blk_exit_rl(struct request_list *rl)
|
|
{
|
|
if (rl->rq_pool)
|
|
mempool_destroy(rl->rq_pool);
|
|
}
|
|
|
|
struct request_queue *blk_alloc_queue(gfp_t gfp_mask)
|
|
{
|
|
return blk_alloc_queue_node(gfp_mask, NUMA_NO_NODE);
|
|
}
|
|
EXPORT_SYMBOL(blk_alloc_queue);
|
|
|
|
int blk_queue_enter(struct request_queue *q, bool nowait)
|
|
{
|
|
while (true) {
|
|
int ret;
|
|
|
|
if (percpu_ref_tryget_live(&q->q_usage_counter))
|
|
return 0;
|
|
|
|
if (nowait)
|
|
return -EBUSY;
|
|
|
|
ret = wait_event_interruptible(q->mq_freeze_wq,
|
|
!atomic_read(&q->mq_freeze_depth) ||
|
|
blk_queue_dying(q));
|
|
if (blk_queue_dying(q))
|
|
return -ENODEV;
|
|
if (ret)
|
|
return ret;
|
|
}
|
|
}
|
|
|
|
void blk_queue_exit(struct request_queue *q)
|
|
{
|
|
percpu_ref_put(&q->q_usage_counter);
|
|
}
|
|
|
|
static void blk_queue_usage_counter_release(struct percpu_ref *ref)
|
|
{
|
|
struct request_queue *q =
|
|
container_of(ref, struct request_queue, q_usage_counter);
|
|
|
|
wake_up_all(&q->mq_freeze_wq);
|
|
}
|
|
|
|
static void blk_rq_timed_out_timer(unsigned long data)
|
|
{
|
|
struct request_queue *q = (struct request_queue *)data;
|
|
|
|
kblockd_schedule_work(&q->timeout_work);
|
|
}
|
|
|
|
struct request_queue *blk_alloc_queue_node(gfp_t gfp_mask, int node_id)
|
|
{
|
|
struct request_queue *q;
|
|
int err;
|
|
|
|
q = kmem_cache_alloc_node(blk_requestq_cachep,
|
|
gfp_mask | __GFP_ZERO, node_id);
|
|
if (!q)
|
|
return NULL;
|
|
|
|
q->id = ida_simple_get(&blk_queue_ida, 0, 0, gfp_mask);
|
|
if (q->id < 0)
|
|
goto fail_q;
|
|
|
|
q->bio_split = bioset_create(BIO_POOL_SIZE, 0);
|
|
if (!q->bio_split)
|
|
goto fail_id;
|
|
|
|
q->backing_dev_info.ra_pages =
|
|
(VM_MAX_READAHEAD * 1024) / PAGE_SIZE;
|
|
q->backing_dev_info.capabilities = BDI_CAP_CGROUP_WRITEBACK;
|
|
q->backing_dev_info.name = "block";
|
|
q->node = node_id;
|
|
|
|
err = bdi_init(&q->backing_dev_info);
|
|
if (err)
|
|
goto fail_split;
|
|
|
|
setup_timer(&q->backing_dev_info.laptop_mode_wb_timer,
|
|
laptop_mode_timer_fn, (unsigned long) q);
|
|
setup_timer(&q->timeout, blk_rq_timed_out_timer, (unsigned long) q);
|
|
INIT_LIST_HEAD(&q->queue_head);
|
|
INIT_LIST_HEAD(&q->timeout_list);
|
|
INIT_LIST_HEAD(&q->icq_list);
|
|
#ifdef CONFIG_BLK_CGROUP
|
|
INIT_LIST_HEAD(&q->blkg_list);
|
|
#endif
|
|
INIT_DELAYED_WORK(&q->delay_work, blk_delay_work);
|
|
|
|
kobject_init(&q->kobj, &blk_queue_ktype);
|
|
|
|
mutex_init(&q->sysfs_lock);
|
|
spin_lock_init(&q->__queue_lock);
|
|
|
|
/*
|
|
* By default initialize queue_lock to internal lock and driver can
|
|
* override it later if need be.
|
|
*/
|
|
q->queue_lock = &q->__queue_lock;
|
|
|
|
/*
|
|
* A queue starts its life with bypass turned on to avoid
|
|
* unnecessary bypass on/off overhead and nasty surprises during
|
|
* init. The initial bypass will be finished when the queue is
|
|
* registered by blk_register_queue().
|
|
*/
|
|
q->bypass_depth = 1;
|
|
__set_bit(QUEUE_FLAG_BYPASS, &q->queue_flags);
|
|
|
|
init_waitqueue_head(&q->mq_freeze_wq);
|
|
|
|
/*
|
|
* Init percpu_ref in atomic mode so that it's faster to shutdown.
|
|
* See blk_register_queue() for details.
|
|
*/
|
|
if (percpu_ref_init(&q->q_usage_counter,
|
|
blk_queue_usage_counter_release,
|
|
PERCPU_REF_INIT_ATOMIC, GFP_KERNEL))
|
|
goto fail_bdi;
|
|
|
|
if (blkcg_init_queue(q))
|
|
goto fail_ref;
|
|
|
|
return q;
|
|
|
|
fail_ref:
|
|
percpu_ref_exit(&q->q_usage_counter);
|
|
fail_bdi:
|
|
bdi_destroy(&q->backing_dev_info);
|
|
fail_split:
|
|
bioset_free(q->bio_split);
|
|
fail_id:
|
|
ida_simple_remove(&blk_queue_ida, q->id);
|
|
fail_q:
|
|
kmem_cache_free(blk_requestq_cachep, q);
|
|
return NULL;
|
|
}
|
|
EXPORT_SYMBOL(blk_alloc_queue_node);
|
|
|
|
/**
|
|
* blk_init_queue - prepare a request queue for use with a block device
|
|
* @rfn: The function to be called to process requests that have been
|
|
* placed on the queue.
|
|
* @lock: Request queue spin lock
|
|
*
|
|
* Description:
|
|
* If a block device wishes to use the standard request handling procedures,
|
|
* which sorts requests and coalesces adjacent requests, then it must
|
|
* call blk_init_queue(). The function @rfn will be called when there
|
|
* are requests on the queue that need to be processed. If the device
|
|
* supports plugging, then @rfn may not be called immediately when requests
|
|
* are available on the queue, but may be called at some time later instead.
|
|
* Plugged queues are generally unplugged when a buffer belonging to one
|
|
* of the requests on the queue is needed, or due to memory pressure.
|
|
*
|
|
* @rfn is not required, or even expected, to remove all requests off the
|
|
* queue, but only as many as it can handle at a time. If it does leave
|
|
* requests on the queue, it is responsible for arranging that the requests
|
|
* get dealt with eventually.
|
|
*
|
|
* The queue spin lock must be held while manipulating the requests on the
|
|
* request queue; this lock will be taken also from interrupt context, so irq
|
|
* disabling is needed for it.
|
|
*
|
|
* Function returns a pointer to the initialized request queue, or %NULL if
|
|
* it didn't succeed.
|
|
*
|
|
* Note:
|
|
* blk_init_queue() must be paired with a blk_cleanup_queue() call
|
|
* when the block device is deactivated (such as at module unload).
|
|
**/
|
|
|
|
struct request_queue *blk_init_queue(request_fn_proc *rfn, spinlock_t *lock)
|
|
{
|
|
return blk_init_queue_node(rfn, lock, NUMA_NO_NODE);
|
|
}
|
|
EXPORT_SYMBOL(blk_init_queue);
|
|
|
|
struct request_queue *
|
|
blk_init_queue_node(request_fn_proc *rfn, spinlock_t *lock, int node_id)
|
|
{
|
|
struct request_queue *uninit_q, *q;
|
|
|
|
uninit_q = blk_alloc_queue_node(GFP_KERNEL, node_id);
|
|
if (!uninit_q)
|
|
return NULL;
|
|
|
|
q = blk_init_allocated_queue(uninit_q, rfn, lock);
|
|
if (!q)
|
|
blk_cleanup_queue(uninit_q);
|
|
|
|
return q;
|
|
}
|
|
EXPORT_SYMBOL(blk_init_queue_node);
|
|
|
|
static blk_qc_t blk_queue_bio(struct request_queue *q, struct bio *bio);
|
|
|
|
struct request_queue *
|
|
blk_init_allocated_queue(struct request_queue *q, request_fn_proc *rfn,
|
|
spinlock_t *lock)
|
|
{
|
|
if (!q)
|
|
return NULL;
|
|
|
|
q->fq = blk_alloc_flush_queue(q, NUMA_NO_NODE, 0);
|
|
if (!q->fq)
|
|
return NULL;
|
|
|
|
if (blk_init_rl(&q->root_rl, q, GFP_KERNEL))
|
|
goto fail;
|
|
|
|
INIT_WORK(&q->timeout_work, blk_timeout_work);
|
|
q->request_fn = rfn;
|
|
q->prep_rq_fn = NULL;
|
|
q->unprep_rq_fn = NULL;
|
|
q->queue_flags |= QUEUE_FLAG_DEFAULT;
|
|
|
|
/* Override internal queue lock with supplied lock pointer */
|
|
if (lock)
|
|
q->queue_lock = lock;
|
|
|
|
/*
|
|
* This also sets hw/phys segments, boundary and size
|
|
*/
|
|
blk_queue_make_request(q, blk_queue_bio);
|
|
|
|
q->sg_reserved_size = INT_MAX;
|
|
|
|
/* Protect q->elevator from elevator_change */
|
|
mutex_lock(&q->sysfs_lock);
|
|
|
|
/* init elevator */
|
|
if (elevator_init(q, NULL)) {
|
|
mutex_unlock(&q->sysfs_lock);
|
|
goto fail;
|
|
}
|
|
|
|
mutex_unlock(&q->sysfs_lock);
|
|
|
|
return q;
|
|
|
|
fail:
|
|
blk_free_flush_queue(q->fq);
|
|
wbt_exit(q);
|
|
return NULL;
|
|
}
|
|
EXPORT_SYMBOL(blk_init_allocated_queue);
|
|
|
|
bool blk_get_queue(struct request_queue *q)
|
|
{
|
|
if (likely(!blk_queue_dying(q))) {
|
|
__blk_get_queue(q);
|
|
return true;
|
|
}
|
|
|
|
return false;
|
|
}
|
|
EXPORT_SYMBOL(blk_get_queue);
|
|
|
|
static inline void blk_free_request(struct request_list *rl, struct request *rq)
|
|
{
|
|
if (rq->rq_flags & RQF_ELVPRIV) {
|
|
elv_put_request(rl->q, rq);
|
|
if (rq->elv.icq)
|
|
put_io_context(rq->elv.icq->ioc);
|
|
}
|
|
|
|
mempool_free(rq, rl->rq_pool);
|
|
}
|
|
|
|
/*
|
|
* ioc_batching returns true if the ioc is a valid batching request and
|
|
* should be given priority access to a request.
|
|
*/
|
|
static inline int ioc_batching(struct request_queue *q, struct io_context *ioc)
|
|
{
|
|
if (!ioc)
|
|
return 0;
|
|
|
|
/*
|
|
* Make sure the process is able to allocate at least 1 request
|
|
* even if the batch times out, otherwise we could theoretically
|
|
* lose wakeups.
|
|
*/
|
|
return ioc->nr_batch_requests == q->nr_batching ||
|
|
(ioc->nr_batch_requests > 0
|
|
&& time_before(jiffies, ioc->last_waited + BLK_BATCH_TIME));
|
|
}
|
|
|
|
/*
|
|
* ioc_set_batching sets ioc to be a new "batcher" if it is not one. This
|
|
* will cause the process to be a "batcher" on all queues in the system. This
|
|
* is the behaviour we want though - once it gets a wakeup it should be given
|
|
* a nice run.
|
|
*/
|
|
static void ioc_set_batching(struct request_queue *q, struct io_context *ioc)
|
|
{
|
|
if (!ioc || ioc_batching(q, ioc))
|
|
return;
|
|
|
|
ioc->nr_batch_requests = q->nr_batching;
|
|
ioc->last_waited = jiffies;
|
|
}
|
|
|
|
static void __freed_request(struct request_list *rl, int sync)
|
|
{
|
|
struct request_queue *q = rl->q;
|
|
|
|
if (rl->count[sync] < queue_congestion_off_threshold(q))
|
|
blk_clear_congested(rl, sync);
|
|
|
|
if (rl->count[sync] + 1 <= q->nr_requests) {
|
|
if (waitqueue_active(&rl->wait[sync]))
|
|
wake_up(&rl->wait[sync]);
|
|
|
|
blk_clear_rl_full(rl, sync);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* A request has just been released. Account for it, update the full and
|
|
* congestion status, wake up any waiters. Called under q->queue_lock.
|
|
*/
|
|
static void freed_request(struct request_list *rl, bool sync,
|
|
req_flags_t rq_flags)
|
|
{
|
|
struct request_queue *q = rl->q;
|
|
|
|
q->nr_rqs[sync]--;
|
|
rl->count[sync]--;
|
|
if (rq_flags & RQF_ELVPRIV)
|
|
q->nr_rqs_elvpriv--;
|
|
|
|
__freed_request(rl, sync);
|
|
|
|
if (unlikely(rl->starved[sync ^ 1]))
|
|
__freed_request(rl, sync ^ 1);
|
|
}
|
|
|
|
int blk_update_nr_requests(struct request_queue *q, unsigned int nr)
|
|
{
|
|
struct request_list *rl;
|
|
int on_thresh, off_thresh;
|
|
|
|
spin_lock_irq(q->queue_lock);
|
|
q->nr_requests = nr;
|
|
blk_queue_congestion_threshold(q);
|
|
on_thresh = queue_congestion_on_threshold(q);
|
|
off_thresh = queue_congestion_off_threshold(q);
|
|
|
|
blk_queue_for_each_rl(rl, q) {
|
|
if (rl->count[BLK_RW_SYNC] >= on_thresh)
|
|
blk_set_congested(rl, BLK_RW_SYNC);
|
|
else if (rl->count[BLK_RW_SYNC] < off_thresh)
|
|
blk_clear_congested(rl, BLK_RW_SYNC);
|
|
|
|
if (rl->count[BLK_RW_ASYNC] >= on_thresh)
|
|
blk_set_congested(rl, BLK_RW_ASYNC);
|
|
else if (rl->count[BLK_RW_ASYNC] < off_thresh)
|
|
blk_clear_congested(rl, BLK_RW_ASYNC);
|
|
|
|
if (rl->count[BLK_RW_SYNC] >= q->nr_requests) {
|
|
blk_set_rl_full(rl, BLK_RW_SYNC);
|
|
} else {
|
|
blk_clear_rl_full(rl, BLK_RW_SYNC);
|
|
wake_up(&rl->wait[BLK_RW_SYNC]);
|
|
}
|
|
|
|
if (rl->count[BLK_RW_ASYNC] >= q->nr_requests) {
|
|
blk_set_rl_full(rl, BLK_RW_ASYNC);
|
|
} else {
|
|
blk_clear_rl_full(rl, BLK_RW_ASYNC);
|
|
wake_up(&rl->wait[BLK_RW_ASYNC]);
|
|
}
|
|
}
|
|
|
|
spin_unlock_irq(q->queue_lock);
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* Determine if elevator data should be initialized when allocating the
|
|
* request associated with @bio.
|
|
*/
|
|
static bool blk_rq_should_init_elevator(struct bio *bio)
|
|
{
|
|
if (!bio)
|
|
return true;
|
|
|
|
/*
|
|
* Flush requests do not use the elevator so skip initialization.
|
|
* This allows a request to share the flush and elevator data.
|
|
*/
|
|
if (op_is_flush(bio->bi_opf))
|
|
return false;
|
|
|
|
return true;
|
|
}
|
|
|
|
/**
|
|
* __get_request - get a free request
|
|
* @rl: request list to allocate from
|
|
* @op: operation and flags
|
|
* @bio: bio to allocate request for (can be %NULL)
|
|
* @gfp_mask: allocation mask
|
|
*
|
|
* Get a free request from @q. This function may fail under memory
|
|
* pressure or if @q is dead.
|
|
*
|
|
* Must be called with @q->queue_lock held and,
|
|
* Returns ERR_PTR on failure, with @q->queue_lock held.
|
|
* Returns request pointer on success, with @q->queue_lock *not held*.
|
|
*/
|
|
static struct request *__get_request(struct request_list *rl, unsigned int op,
|
|
struct bio *bio, gfp_t gfp_mask)
|
|
{
|
|
struct request_queue *q = rl->q;
|
|
struct request *rq;
|
|
struct elevator_type *et = q->elevator->type;
|
|
struct io_context *ioc = rq_ioc(bio);
|
|
struct io_cq *icq = NULL;
|
|
const bool is_sync = op_is_sync(op);
|
|
int may_queue;
|
|
req_flags_t rq_flags = RQF_ALLOCED;
|
|
|
|
if (unlikely(blk_queue_dying(q)))
|
|
return ERR_PTR(-ENODEV);
|
|
|
|
may_queue = elv_may_queue(q, op);
|
|
if (may_queue == ELV_MQUEUE_NO)
|
|
goto rq_starved;
|
|
|
|
if (rl->count[is_sync]+1 >= queue_congestion_on_threshold(q)) {
|
|
if (rl->count[is_sync]+1 >= q->nr_requests) {
|
|
/*
|
|
* The queue will fill after this allocation, so set
|
|
* it as full, and mark this process as "batching".
|
|
* This process will be allowed to complete a batch of
|
|
* requests, others will be blocked.
|
|
*/
|
|
if (!blk_rl_full(rl, is_sync)) {
|
|
ioc_set_batching(q, ioc);
|
|
blk_set_rl_full(rl, is_sync);
|
|
} else {
|
|
if (may_queue != ELV_MQUEUE_MUST
|
|
&& !ioc_batching(q, ioc)) {
|
|
/*
|
|
* The queue is full and the allocating
|
|
* process is not a "batcher", and not
|
|
* exempted by the IO scheduler
|
|
*/
|
|
return ERR_PTR(-ENOMEM);
|
|
}
|
|
}
|
|
}
|
|
blk_set_congested(rl, is_sync);
|
|
}
|
|
|
|
/*
|
|
* Only allow batching queuers to allocate up to 50% over the defined
|
|
* limit of requests, otherwise we could have thousands of requests
|
|
* allocated with any setting of ->nr_requests
|
|
*/
|
|
if (rl->count[is_sync] >= (3 * q->nr_requests / 2))
|
|
return ERR_PTR(-ENOMEM);
|
|
|
|
q->nr_rqs[is_sync]++;
|
|
rl->count[is_sync]++;
|
|
rl->starved[is_sync] = 0;
|
|
|
|
/*
|
|
* Decide whether the new request will be managed by elevator. If
|
|
* so, mark @rq_flags and increment elvpriv. Non-zero elvpriv will
|
|
* prevent the current elevator from being destroyed until the new
|
|
* request is freed. This guarantees icq's won't be destroyed and
|
|
* makes creating new ones safe.
|
|
*
|
|
* Also, lookup icq while holding queue_lock. If it doesn't exist,
|
|
* it will be created after releasing queue_lock.
|
|
*/
|
|
if (blk_rq_should_init_elevator(bio) && !blk_queue_bypass(q)) {
|
|
rq_flags |= RQF_ELVPRIV;
|
|
q->nr_rqs_elvpriv++;
|
|
if (et->icq_cache && ioc)
|
|
icq = ioc_lookup_icq(ioc, q);
|
|
}
|
|
|
|
if (blk_queue_io_stat(q))
|
|
rq_flags |= RQF_IO_STAT;
|
|
spin_unlock_irq(q->queue_lock);
|
|
|
|
/* allocate and init request */
|
|
rq = mempool_alloc(rl->rq_pool, gfp_mask);
|
|
if (!rq)
|
|
goto fail_alloc;
|
|
|
|
blk_rq_init(q, rq);
|
|
blk_rq_set_rl(rq, rl);
|
|
blk_rq_set_prio(rq, ioc);
|
|
rq->cmd_flags = op;
|
|
rq->rq_flags = rq_flags;
|
|
|
|
/* init elvpriv */
|
|
if (rq_flags & RQF_ELVPRIV) {
|
|
if (unlikely(et->icq_cache && !icq)) {
|
|
if (ioc)
|
|
icq = ioc_create_icq(ioc, q, gfp_mask);
|
|
if (!icq)
|
|
goto fail_elvpriv;
|
|
}
|
|
|
|
rq->elv.icq = icq;
|
|
if (unlikely(elv_set_request(q, rq, bio, gfp_mask)))
|
|
goto fail_elvpriv;
|
|
|
|
/* @rq->elv.icq holds io_context until @rq is freed */
|
|
if (icq)
|
|
get_io_context(icq->ioc);
|
|
}
|
|
out:
|
|
/*
|
|
* ioc may be NULL here, and ioc_batching will be false. That's
|
|
* OK, if the queue is under the request limit then requests need
|
|
* not count toward the nr_batch_requests limit. There will always
|
|
* be some limit enforced by BLK_BATCH_TIME.
|
|
*/
|
|
if (ioc_batching(q, ioc))
|
|
ioc->nr_batch_requests--;
|
|
|
|
trace_block_getrq(q, bio, op);
|
|
return rq;
|
|
|
|
fail_elvpriv:
|
|
/*
|
|
* elvpriv init failed. ioc, icq and elvpriv aren't mempool backed
|
|
* and may fail indefinitely under memory pressure and thus
|
|
* shouldn't stall IO. Treat this request as !elvpriv. This will
|
|
* disturb iosched and blkcg but weird is bettern than dead.
|
|
*/
|
|
printk_ratelimited(KERN_WARNING "%s: dev %s: request aux data allocation failed, iosched may be disturbed\n",
|
|
__func__, dev_name(q->backing_dev_info.dev));
|
|
|
|
rq->rq_flags &= ~RQF_ELVPRIV;
|
|
rq->elv.icq = NULL;
|
|
|
|
spin_lock_irq(q->queue_lock);
|
|
q->nr_rqs_elvpriv--;
|
|
spin_unlock_irq(q->queue_lock);
|
|
goto out;
|
|
|
|
fail_alloc:
|
|
/*
|
|
* Allocation failed presumably due to memory. Undo anything we
|
|
* might have messed up.
|
|
*
|
|
* Allocating task should really be put onto the front of the wait
|
|
* queue, but this is pretty rare.
|
|
*/
|
|
spin_lock_irq(q->queue_lock);
|
|
freed_request(rl, is_sync, rq_flags);
|
|
|
|
/*
|
|
* in the very unlikely event that allocation failed and no
|
|
* requests for this direction was pending, mark us starved so that
|
|
* freeing of a request in the other direction will notice
|
|
* us. another possible fix would be to split the rq mempool into
|
|
* READ and WRITE
|
|
*/
|
|
rq_starved:
|
|
if (unlikely(rl->count[is_sync] == 0))
|
|
rl->starved[is_sync] = 1;
|
|
return ERR_PTR(-ENOMEM);
|
|
}
|
|
|
|
/**
|
|
* get_request - get a free request
|
|
* @q: request_queue to allocate request from
|
|
* @op: operation and flags
|
|
* @bio: bio to allocate request for (can be %NULL)
|
|
* @gfp_mask: allocation mask
|
|
*
|
|
* Get a free request from @q. If %__GFP_DIRECT_RECLAIM is set in @gfp_mask,
|
|
* this function keeps retrying under memory pressure and fails iff @q is dead.
|
|
*
|
|
* Must be called with @q->queue_lock held and,
|
|
* Returns ERR_PTR on failure, with @q->queue_lock held.
|
|
* Returns request pointer on success, with @q->queue_lock *not held*.
|
|
*/
|
|
static struct request *get_request(struct request_queue *q, unsigned int op,
|
|
struct bio *bio, gfp_t gfp_mask)
|
|
{
|
|
const bool is_sync = op_is_sync(op);
|
|
DEFINE_WAIT(wait);
|
|
struct request_list *rl;
|
|
struct request *rq;
|
|
|
|
rl = blk_get_rl(q, bio); /* transferred to @rq on success */
|
|
retry:
|
|
rq = __get_request(rl, op, bio, gfp_mask);
|
|
if (!IS_ERR(rq))
|
|
return rq;
|
|
|
|
if (!gfpflags_allow_blocking(gfp_mask) || unlikely(blk_queue_dying(q))) {
|
|
blk_put_rl(rl);
|
|
return rq;
|
|
}
|
|
|
|
/* wait on @rl and retry */
|
|
prepare_to_wait_exclusive(&rl->wait[is_sync], &wait,
|
|
TASK_UNINTERRUPTIBLE);
|
|
|
|
trace_block_sleeprq(q, bio, op);
|
|
|
|
spin_unlock_irq(q->queue_lock);
|
|
io_schedule();
|
|
|
|
/*
|
|
* After sleeping, we become a "batching" process and will be able
|
|
* to allocate at least one request, and up to a big batch of them
|
|
* for a small period time. See ioc_batching, ioc_set_batching
|
|
*/
|
|
ioc_set_batching(q, current->io_context);
|
|
|
|
spin_lock_irq(q->queue_lock);
|
|
finish_wait(&rl->wait[is_sync], &wait);
|
|
|
|
goto retry;
|
|
}
|
|
|
|
static struct request *blk_old_get_request(struct request_queue *q, int rw,
|
|
gfp_t gfp_mask)
|
|
{
|
|
struct request *rq;
|
|
|
|
BUG_ON(rw != READ && rw != WRITE);
|
|
|
|
/* create ioc upfront */
|
|
create_io_context(gfp_mask, q->node);
|
|
|
|
spin_lock_irq(q->queue_lock);
|
|
rq = get_request(q, rw, NULL, gfp_mask);
|
|
if (IS_ERR(rq)) {
|
|
spin_unlock_irq(q->queue_lock);
|
|
return rq;
|
|
}
|
|
|
|
/* q->queue_lock is unlocked at this point */
|
|
rq->__data_len = 0;
|
|
rq->__sector = (sector_t) -1;
|
|
rq->bio = rq->biotail = NULL;
|
|
return rq;
|
|
}
|
|
|
|
struct request *blk_get_request(struct request_queue *q, int rw, gfp_t gfp_mask)
|
|
{
|
|
if (q->mq_ops)
|
|
return blk_mq_alloc_request(q, rw,
|
|
(gfp_mask & __GFP_DIRECT_RECLAIM) ?
|
|
0 : BLK_MQ_REQ_NOWAIT);
|
|
else
|
|
return blk_old_get_request(q, rw, gfp_mask);
|
|
}
|
|
EXPORT_SYMBOL(blk_get_request);
|
|
|
|
/**
|
|
* blk_rq_set_block_pc - initialize a request to type BLOCK_PC
|
|
* @rq: request to be initialized
|
|
*
|
|
*/
|
|
void blk_rq_set_block_pc(struct request *rq)
|
|
{
|
|
rq->cmd_type = REQ_TYPE_BLOCK_PC;
|
|
memset(rq->__cmd, 0, sizeof(rq->__cmd));
|
|
}
|
|
EXPORT_SYMBOL(blk_rq_set_block_pc);
|
|
|
|
/**
|
|
* blk_requeue_request - put a request back on queue
|
|
* @q: request queue where request should be inserted
|
|
* @rq: request to be inserted
|
|
*
|
|
* Description:
|
|
* Drivers often keep queueing requests until the hardware cannot accept
|
|
* more, when that condition happens we need to put the request back
|
|
* on the queue. Must be called with queue lock held.
|
|
*/
|
|
void blk_requeue_request(struct request_queue *q, struct request *rq)
|
|
{
|
|
blk_delete_timer(rq);
|
|
blk_clear_rq_complete(rq);
|
|
trace_block_rq_requeue(q, rq);
|
|
wbt_requeue(q->rq_wb, &rq->issue_stat);
|
|
|
|
if (rq->rq_flags & RQF_QUEUED)
|
|
blk_queue_end_tag(q, rq);
|
|
|
|
BUG_ON(blk_queued_rq(rq));
|
|
|
|
elv_requeue_request(q, rq);
|
|
}
|
|
EXPORT_SYMBOL(blk_requeue_request);
|
|
|
|
static void add_acct_request(struct request_queue *q, struct request *rq,
|
|
int where)
|
|
{
|
|
blk_account_io_start(rq, true);
|
|
__elv_add_request(q, rq, where);
|
|
}
|
|
|
|
static void part_round_stats_single(int cpu, struct hd_struct *part,
|
|
unsigned long now)
|
|
{
|
|
int inflight;
|
|
|
|
if (now == part->stamp)
|
|
return;
|
|
|
|
inflight = part_in_flight(part);
|
|
if (inflight) {
|
|
__part_stat_add(cpu, part, time_in_queue,
|
|
inflight * (now - part->stamp));
|
|
__part_stat_add(cpu, part, io_ticks, (now - part->stamp));
|
|
}
|
|
part->stamp = now;
|
|
}
|
|
|
|
/**
|
|
* part_round_stats() - Round off the performance stats on a struct disk_stats.
|
|
* @cpu: cpu number for stats access
|
|
* @part: target partition
|
|
*
|
|
* The average IO queue length and utilisation statistics are maintained
|
|
* by observing the current state of the queue length and the amount of
|
|
* time it has been in this state for.
|
|
*
|
|
* Normally, that accounting is done on IO completion, but that can result
|
|
* in more than a second's worth of IO being accounted for within any one
|
|
* second, leading to >100% utilisation. To deal with that, we call this
|
|
* function to do a round-off before returning the results when reading
|
|
* /proc/diskstats. This accounts immediately for all queue usage up to
|
|
* the current jiffies and restarts the counters again.
|
|
*/
|
|
void part_round_stats(int cpu, struct hd_struct *part)
|
|
{
|
|
unsigned long now = jiffies;
|
|
|
|
if (part->partno)
|
|
part_round_stats_single(cpu, &part_to_disk(part)->part0, now);
|
|
part_round_stats_single(cpu, part, now);
|
|
}
|
|
EXPORT_SYMBOL_GPL(part_round_stats);
|
|
|
|
#ifdef CONFIG_PM
|
|
static void blk_pm_put_request(struct request *rq)
|
|
{
|
|
if (rq->q->dev && !(rq->rq_flags & RQF_PM) && !--rq->q->nr_pending)
|
|
pm_runtime_mark_last_busy(rq->q->dev);
|
|
}
|
|
#else
|
|
static inline void blk_pm_put_request(struct request *rq) {}
|
|
#endif
|
|
|
|
/*
|
|
* queue lock must be held
|
|
*/
|
|
void __blk_put_request(struct request_queue *q, struct request *req)
|
|
{
|
|
req_flags_t rq_flags = req->rq_flags;
|
|
|
|
if (unlikely(!q))
|
|
return;
|
|
|
|
if (q->mq_ops) {
|
|
blk_mq_free_request(req);
|
|
return;
|
|
}
|
|
|
|
blk_pm_put_request(req);
|
|
|
|
elv_completed_request(q, req);
|
|
|
|
/* this is a bio leak */
|
|
WARN_ON(req->bio != NULL);
|
|
|
|
wbt_done(q->rq_wb, &req->issue_stat);
|
|
|
|
/*
|
|
* Request may not have originated from ll_rw_blk. if not,
|
|
* it didn't come out of our reserved rq pools
|
|
*/
|
|
if (rq_flags & RQF_ALLOCED) {
|
|
struct request_list *rl = blk_rq_rl(req);
|
|
bool sync = op_is_sync(req->cmd_flags);
|
|
|
|
BUG_ON(!list_empty(&req->queuelist));
|
|
BUG_ON(ELV_ON_HASH(req));
|
|
|
|
blk_free_request(rl, req);
|
|
freed_request(rl, sync, rq_flags);
|
|
blk_put_rl(rl);
|
|
}
|
|
}
|
|
EXPORT_SYMBOL_GPL(__blk_put_request);
|
|
|
|
void blk_put_request(struct request *req)
|
|
{
|
|
struct request_queue *q = req->q;
|
|
|
|
if (q->mq_ops)
|
|
blk_mq_free_request(req);
|
|
else {
|
|
unsigned long flags;
|
|
|
|
spin_lock_irqsave(q->queue_lock, flags);
|
|
__blk_put_request(q, req);
|
|
spin_unlock_irqrestore(q->queue_lock, flags);
|
|
}
|
|
}
|
|
EXPORT_SYMBOL(blk_put_request);
|
|
|
|
bool bio_attempt_back_merge(struct request_queue *q, struct request *req,
|
|
struct bio *bio)
|
|
{
|
|
const int ff = bio->bi_opf & REQ_FAILFAST_MASK;
|
|
|
|
if (!ll_back_merge_fn(q, req, bio))
|
|
return false;
|
|
|
|
trace_block_bio_backmerge(q, req, bio);
|
|
|
|
if ((req->cmd_flags & REQ_FAILFAST_MASK) != ff)
|
|
blk_rq_set_mixed_merge(req);
|
|
|
|
req->biotail->bi_next = bio;
|
|
req->biotail = bio;
|
|
req->__data_len += bio->bi_iter.bi_size;
|
|
req->ioprio = ioprio_best(req->ioprio, bio_prio(bio));
|
|
|
|
blk_account_io_start(req, false);
|
|
return true;
|
|
}
|
|
|
|
bool bio_attempt_front_merge(struct request_queue *q, struct request *req,
|
|
struct bio *bio)
|
|
{
|
|
const int ff = bio->bi_opf & REQ_FAILFAST_MASK;
|
|
|
|
if (!ll_front_merge_fn(q, req, bio))
|
|
return false;
|
|
|
|
trace_block_bio_frontmerge(q, req, bio);
|
|
|
|
if ((req->cmd_flags & REQ_FAILFAST_MASK) != ff)
|
|
blk_rq_set_mixed_merge(req);
|
|
|
|
bio->bi_next = req->bio;
|
|
req->bio = bio;
|
|
|
|
req->__sector = bio->bi_iter.bi_sector;
|
|
req->__data_len += bio->bi_iter.bi_size;
|
|
req->ioprio = ioprio_best(req->ioprio, bio_prio(bio));
|
|
|
|
blk_account_io_start(req, false);
|
|
return true;
|
|
}
|
|
|
|
/**
|
|
* blk_attempt_plug_merge - try to merge with %current's plugged list
|
|
* @q: request_queue new bio is being queued at
|
|
* @bio: new bio being queued
|
|
* @request_count: out parameter for number of traversed plugged requests
|
|
* @same_queue_rq: pointer to &struct request that gets filled in when
|
|
* another request associated with @q is found on the plug list
|
|
* (optional, may be %NULL)
|
|
*
|
|
* Determine whether @bio being queued on @q can be merged with a request
|
|
* on %current's plugged list. Returns %true if merge was successful,
|
|
* otherwise %false.
|
|
*
|
|
* Plugging coalesces IOs from the same issuer for the same purpose without
|
|
* going through @q->queue_lock. As such it's more of an issuing mechanism
|
|
* than scheduling, and the request, while may have elvpriv data, is not
|
|
* added on the elevator at this point. In addition, we don't have
|
|
* reliable access to the elevator outside queue lock. Only check basic
|
|
* merging parameters without querying the elevator.
|
|
*
|
|
* Caller must ensure !blk_queue_nomerges(q) beforehand.
|
|
*/
|
|
bool blk_attempt_plug_merge(struct request_queue *q, struct bio *bio,
|
|
unsigned int *request_count,
|
|
struct request **same_queue_rq)
|
|
{
|
|
struct blk_plug *plug;
|
|
struct request *rq;
|
|
bool ret = false;
|
|
struct list_head *plug_list;
|
|
|
|
plug = current->plug;
|
|
if (!plug)
|
|
goto out;
|
|
*request_count = 0;
|
|
|
|
if (q->mq_ops)
|
|
plug_list = &plug->mq_list;
|
|
else
|
|
plug_list = &plug->list;
|
|
|
|
list_for_each_entry_reverse(rq, plug_list, queuelist) {
|
|
int el_ret;
|
|
|
|
if (rq->q == q) {
|
|
(*request_count)++;
|
|
/*
|
|
* Only blk-mq multiple hardware queues case checks the
|
|
* rq in the same queue, there should be only one such
|
|
* rq in a queue
|
|
**/
|
|
if (same_queue_rq)
|
|
*same_queue_rq = rq;
|
|
}
|
|
|
|
if (rq->q != q || !blk_rq_merge_ok(rq, bio))
|
|
continue;
|
|
|
|
el_ret = blk_try_merge(rq, bio);
|
|
if (el_ret == ELEVATOR_BACK_MERGE) {
|
|
ret = bio_attempt_back_merge(q, rq, bio);
|
|
if (ret)
|
|
break;
|
|
} else if (el_ret == ELEVATOR_FRONT_MERGE) {
|
|
ret = bio_attempt_front_merge(q, rq, bio);
|
|
if (ret)
|
|
break;
|
|
}
|
|
}
|
|
out:
|
|
return ret;
|
|
}
|
|
|
|
unsigned int blk_plug_queued_count(struct request_queue *q)
|
|
{
|
|
struct blk_plug *plug;
|
|
struct request *rq;
|
|
struct list_head *plug_list;
|
|
unsigned int ret = 0;
|
|
|
|
plug = current->plug;
|
|
if (!plug)
|
|
goto out;
|
|
|
|
if (q->mq_ops)
|
|
plug_list = &plug->mq_list;
|
|
else
|
|
plug_list = &plug->list;
|
|
|
|
list_for_each_entry(rq, plug_list, queuelist) {
|
|
if (rq->q == q)
|
|
ret++;
|
|
}
|
|
out:
|
|
return ret;
|
|
}
|
|
|
|
void init_request_from_bio(struct request *req, struct bio *bio)
|
|
{
|
|
req->cmd_type = REQ_TYPE_FS;
|
|
if (bio->bi_opf & REQ_RAHEAD)
|
|
req->cmd_flags |= REQ_FAILFAST_MASK;
|
|
|
|
req->errors = 0;
|
|
req->__sector = bio->bi_iter.bi_sector;
|
|
if (ioprio_valid(bio_prio(bio)))
|
|
req->ioprio = bio_prio(bio);
|
|
blk_rq_bio_prep(req->q, req, bio);
|
|
}
|
|
|
|
static blk_qc_t blk_queue_bio(struct request_queue *q, struct bio *bio)
|
|
{
|
|
struct blk_plug *plug;
|
|
int el_ret, where = ELEVATOR_INSERT_SORT;
|
|
struct request *req;
|
|
unsigned int request_count = 0;
|
|
unsigned int wb_acct;
|
|
|
|
/*
|
|
* low level driver can indicate that it wants pages above a
|
|
* certain limit bounced to low memory (ie for highmem, or even
|
|
* ISA dma in theory)
|
|
*/
|
|
blk_queue_bounce(q, &bio);
|
|
|
|
blk_queue_split(q, &bio, q->bio_split);
|
|
|
|
if (bio_integrity_enabled(bio) && bio_integrity_prep(bio)) {
|
|
bio->bi_error = -EIO;
|
|
bio_endio(bio);
|
|
return BLK_QC_T_NONE;
|
|
}
|
|
|
|
if (op_is_flush(bio->bi_opf)) {
|
|
spin_lock_irq(q->queue_lock);
|
|
where = ELEVATOR_INSERT_FLUSH;
|
|
goto get_rq;
|
|
}
|
|
|
|
/*
|
|
* Check if we can merge with the plugged list before grabbing
|
|
* any locks.
|
|
*/
|
|
if (!blk_queue_nomerges(q)) {
|
|
if (blk_attempt_plug_merge(q, bio, &request_count, NULL))
|
|
return BLK_QC_T_NONE;
|
|
} else
|
|
request_count = blk_plug_queued_count(q);
|
|
|
|
spin_lock_irq(q->queue_lock);
|
|
|
|
el_ret = elv_merge(q, &req, bio);
|
|
if (el_ret == ELEVATOR_BACK_MERGE) {
|
|
if (bio_attempt_back_merge(q, req, bio)) {
|
|
elv_bio_merged(q, req, bio);
|
|
if (!attempt_back_merge(q, req))
|
|
elv_merged_request(q, req, el_ret);
|
|
goto out_unlock;
|
|
}
|
|
} else if (el_ret == ELEVATOR_FRONT_MERGE) {
|
|
if (bio_attempt_front_merge(q, req, bio)) {
|
|
elv_bio_merged(q, req, bio);
|
|
if (!attempt_front_merge(q, req))
|
|
elv_merged_request(q, req, el_ret);
|
|
goto out_unlock;
|
|
}
|
|
}
|
|
|
|
get_rq:
|
|
wb_acct = wbt_wait(q->rq_wb, bio, q->queue_lock);
|
|
|
|
/*
|
|
* Grab a free request. This is might sleep but can not fail.
|
|
* Returns with the queue unlocked.
|
|
*/
|
|
req = get_request(q, bio->bi_opf, bio, GFP_NOIO);
|
|
if (IS_ERR(req)) {
|
|
__wbt_done(q->rq_wb, wb_acct);
|
|
bio->bi_error = PTR_ERR(req);
|
|
bio_endio(bio);
|
|
goto out_unlock;
|
|
}
|
|
|
|
wbt_track(&req->issue_stat, wb_acct);
|
|
|
|
/*
|
|
* After dropping the lock and possibly sleeping here, our request
|
|
* may now be mergeable after it had proven unmergeable (above).
|
|
* We don't worry about that case for efficiency. It won't happen
|
|
* often, and the elevators are able to handle it.
|
|
*/
|
|
init_request_from_bio(req, bio);
|
|
|
|
if (test_bit(QUEUE_FLAG_SAME_COMP, &q->queue_flags))
|
|
req->cpu = raw_smp_processor_id();
|
|
|
|
plug = current->plug;
|
|
if (plug) {
|
|
/*
|
|
* If this is the first request added after a plug, fire
|
|
* of a plug trace.
|
|
*
|
|
* @request_count may become stale because of schedule
|
|
* out, so check plug list again.
|
|
*/
|
|
if (!request_count || list_empty(&plug->list))
|
|
trace_block_plug(q);
|
|
else {
|
|
struct request *last = list_entry_rq(plug->list.prev);
|
|
if (request_count >= BLK_MAX_REQUEST_COUNT ||
|
|
blk_rq_bytes(last) >= BLK_PLUG_FLUSH_SIZE) {
|
|
blk_flush_plug_list(plug, false);
|
|
trace_block_plug(q);
|
|
}
|
|
}
|
|
list_add_tail(&req->queuelist, &plug->list);
|
|
blk_account_io_start(req, true);
|
|
} else {
|
|
spin_lock_irq(q->queue_lock);
|
|
add_acct_request(q, req, where);
|
|
__blk_run_queue(q);
|
|
out_unlock:
|
|
spin_unlock_irq(q->queue_lock);
|
|
}
|
|
|
|
return BLK_QC_T_NONE;
|
|
}
|
|
|
|
/*
|
|
* If bio->bi_dev is a partition, remap the location
|
|
*/
|
|
static inline void blk_partition_remap(struct bio *bio)
|
|
{
|
|
struct block_device *bdev = bio->bi_bdev;
|
|
|
|
/*
|
|
* Zone reset does not include bi_size so bio_sectors() is always 0.
|
|
* Include a test for the reset op code and perform the remap if needed.
|
|
*/
|
|
if (bdev != bdev->bd_contains &&
|
|
(bio_sectors(bio) || bio_op(bio) == REQ_OP_ZONE_RESET)) {
|
|
struct hd_struct *p = bdev->bd_part;
|
|
|
|
bio->bi_iter.bi_sector += p->start_sect;
|
|
bio->bi_bdev = bdev->bd_contains;
|
|
|
|
trace_block_bio_remap(bdev_get_queue(bio->bi_bdev), bio,
|
|
bdev->bd_dev,
|
|
bio->bi_iter.bi_sector - p->start_sect);
|
|
}
|
|
}
|
|
|
|
static void handle_bad_sector(struct bio *bio)
|
|
{
|
|
char b[BDEVNAME_SIZE];
|
|
|
|
printk(KERN_INFO "attempt to access beyond end of device\n");
|
|
printk(KERN_INFO "%s: rw=%d, want=%Lu, limit=%Lu\n",
|
|
bdevname(bio->bi_bdev, b),
|
|
bio->bi_opf,
|
|
(unsigned long long)bio_end_sector(bio),
|
|
(long long)(i_size_read(bio->bi_bdev->bd_inode) >> 9));
|
|
}
|
|
|
|
#ifdef CONFIG_FAIL_MAKE_REQUEST
|
|
|
|
static DECLARE_FAULT_ATTR(fail_make_request);
|
|
|
|
static int __init setup_fail_make_request(char *str)
|
|
{
|
|
return setup_fault_attr(&fail_make_request, str);
|
|
}
|
|
__setup("fail_make_request=", setup_fail_make_request);
|
|
|
|
static bool should_fail_request(struct hd_struct *part, unsigned int bytes)
|
|
{
|
|
return part->make_it_fail && should_fail(&fail_make_request, bytes);
|
|
}
|
|
|
|
static int __init fail_make_request_debugfs(void)
|
|
{
|
|
struct dentry *dir = fault_create_debugfs_attr("fail_make_request",
|
|
NULL, &fail_make_request);
|
|
|
|
return PTR_ERR_OR_ZERO(dir);
|
|
}
|
|
|
|
late_initcall(fail_make_request_debugfs);
|
|
|
|
#else /* CONFIG_FAIL_MAKE_REQUEST */
|
|
|
|
static inline bool should_fail_request(struct hd_struct *part,
|
|
unsigned int bytes)
|
|
{
|
|
return false;
|
|
}
|
|
|
|
#endif /* CONFIG_FAIL_MAKE_REQUEST */
|
|
|
|
/*
|
|
* Check whether this bio extends beyond the end of the device.
|
|
*/
|
|
static inline int bio_check_eod(struct bio *bio, unsigned int nr_sectors)
|
|
{
|
|
sector_t maxsector;
|
|
|
|
if (!nr_sectors)
|
|
return 0;
|
|
|
|
/* Test device or partition size, when known. */
|
|
maxsector = i_size_read(bio->bi_bdev->bd_inode) >> 9;
|
|
if (maxsector) {
|
|
sector_t sector = bio->bi_iter.bi_sector;
|
|
|
|
if (maxsector < nr_sectors || maxsector - nr_sectors < sector) {
|
|
/*
|
|
* This may well happen - the kernel calls bread()
|
|
* without checking the size of the device, e.g., when
|
|
* mounting a device.
|
|
*/
|
|
handle_bad_sector(bio);
|
|
return 1;
|
|
}
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
static noinline_for_stack bool
|
|
generic_make_request_checks(struct bio *bio)
|
|
{
|
|
struct request_queue *q;
|
|
int nr_sectors = bio_sectors(bio);
|
|
int err = -EIO;
|
|
char b[BDEVNAME_SIZE];
|
|
struct hd_struct *part;
|
|
|
|
might_sleep();
|
|
|
|
if (bio_check_eod(bio, nr_sectors))
|
|
goto end_io;
|
|
|
|
q = bdev_get_queue(bio->bi_bdev);
|
|
if (unlikely(!q)) {
|
|
printk(KERN_ERR
|
|
"generic_make_request: Trying to access "
|
|
"nonexistent block-device %s (%Lu)\n",
|
|
bdevname(bio->bi_bdev, b),
|
|
(long long) bio->bi_iter.bi_sector);
|
|
goto end_io;
|
|
}
|
|
|
|
part = bio->bi_bdev->bd_part;
|
|
if (should_fail_request(part, bio->bi_iter.bi_size) ||
|
|
should_fail_request(&part_to_disk(part)->part0,
|
|
bio->bi_iter.bi_size))
|
|
goto end_io;
|
|
|
|
/*
|
|
* If this device has partitions, remap block n
|
|
* of partition p to block n+start(p) of the disk.
|
|
*/
|
|
blk_partition_remap(bio);
|
|
|
|
if (bio_check_eod(bio, nr_sectors))
|
|
goto end_io;
|
|
|
|
/*
|
|
* Filter flush bio's early so that make_request based
|
|
* drivers without flush support don't have to worry
|
|
* about them.
|
|
*/
|
|
if (op_is_flush(bio->bi_opf) &&
|
|
!test_bit(QUEUE_FLAG_WC, &q->queue_flags)) {
|
|
bio->bi_opf &= ~(REQ_PREFLUSH | REQ_FUA);
|
|
if (!nr_sectors) {
|
|
err = 0;
|
|
goto end_io;
|
|
}
|
|
}
|
|
|
|
switch (bio_op(bio)) {
|
|
case REQ_OP_DISCARD:
|
|
if (!blk_queue_discard(q))
|
|
goto not_supported;
|
|
break;
|
|
case REQ_OP_SECURE_ERASE:
|
|
if (!blk_queue_secure_erase(q))
|
|
goto not_supported;
|
|
break;
|
|
case REQ_OP_WRITE_SAME:
|
|
if (!bdev_write_same(bio->bi_bdev))
|
|
goto not_supported;
|
|
break;
|
|
case REQ_OP_ZONE_REPORT:
|
|
case REQ_OP_ZONE_RESET:
|
|
if (!bdev_is_zoned(bio->bi_bdev))
|
|
goto not_supported;
|
|
break;
|
|
case REQ_OP_WRITE_ZEROES:
|
|
if (!bdev_write_zeroes_sectors(bio->bi_bdev))
|
|
goto not_supported;
|
|
break;
|
|
default:
|
|
break;
|
|
}
|
|
|
|
/*
|
|
* Various block parts want %current->io_context and lazy ioc
|
|
* allocation ends up trading a lot of pain for a small amount of
|
|
* memory. Just allocate it upfront. This may fail and block
|
|
* layer knows how to live with it.
|
|
*/
|
|
create_io_context(GFP_ATOMIC, q->node);
|
|
|
|
if (!blkcg_bio_issue_check(q, bio))
|
|
return false;
|
|
|
|
trace_block_bio_queue(q, bio);
|
|
return true;
|
|
|
|
not_supported:
|
|
err = -EOPNOTSUPP;
|
|
end_io:
|
|
bio->bi_error = err;
|
|
bio_endio(bio);
|
|
return false;
|
|
}
|
|
|
|
/**
|
|
* generic_make_request - hand a buffer to its device driver for I/O
|
|
* @bio: The bio describing the location in memory and on the device.
|
|
*
|
|
* generic_make_request() is used to make I/O requests of block
|
|
* devices. It is passed a &struct bio, which describes the I/O that needs
|
|
* to be done.
|
|
*
|
|
* generic_make_request() does not return any status. The
|
|
* success/failure status of the request, along with notification of
|
|
* completion, is delivered asynchronously through the bio->bi_end_io
|
|
* function described (one day) else where.
|
|
*
|
|
* The caller of generic_make_request must make sure that bi_io_vec
|
|
* are set to describe the memory buffer, and that bi_dev and bi_sector are
|
|
* set to describe the device address, and the
|
|
* bi_end_io and optionally bi_private are set to describe how
|
|
* completion notification should be signaled.
|
|
*
|
|
* generic_make_request and the drivers it calls may use bi_next if this
|
|
* bio happens to be merged with someone else, and may resubmit the bio to
|
|
* a lower device by calling into generic_make_request recursively, which
|
|
* means the bio should NOT be touched after the call to ->make_request_fn.
|
|
*/
|
|
blk_qc_t generic_make_request(struct bio *bio)
|
|
{
|
|
struct bio_list bio_list_on_stack;
|
|
blk_qc_t ret = BLK_QC_T_NONE;
|
|
|
|
if (!generic_make_request_checks(bio))
|
|
goto out;
|
|
|
|
/*
|
|
* We only want one ->make_request_fn to be active at a time, else
|
|
* stack usage with stacked devices could be a problem. So use
|
|
* current->bio_list to keep a list of requests submited by a
|
|
* make_request_fn function. current->bio_list is also used as a
|
|
* flag to say if generic_make_request is currently active in this
|
|
* task or not. If it is NULL, then no make_request is active. If
|
|
* it is non-NULL, then a make_request is active, and new requests
|
|
* should be added at the tail
|
|
*/
|
|
if (current->bio_list) {
|
|
bio_list_add(current->bio_list, bio);
|
|
goto out;
|
|
}
|
|
|
|
/* following loop may be a bit non-obvious, and so deserves some
|
|
* explanation.
|
|
* Before entering the loop, bio->bi_next is NULL (as all callers
|
|
* ensure that) so we have a list with a single bio.
|
|
* We pretend that we have just taken it off a longer list, so
|
|
* we assign bio_list to a pointer to the bio_list_on_stack,
|
|
* thus initialising the bio_list of new bios to be
|
|
* added. ->make_request() may indeed add some more bios
|
|
* through a recursive call to generic_make_request. If it
|
|
* did, we find a non-NULL value in bio_list and re-enter the loop
|
|
* from the top. In this case we really did just take the bio
|
|
* of the top of the list (no pretending) and so remove it from
|
|
* bio_list, and call into ->make_request() again.
|
|
*/
|
|
BUG_ON(bio->bi_next);
|
|
bio_list_init(&bio_list_on_stack);
|
|
current->bio_list = &bio_list_on_stack;
|
|
do {
|
|
struct request_queue *q = bdev_get_queue(bio->bi_bdev);
|
|
|
|
if (likely(blk_queue_enter(q, false) == 0)) {
|
|
ret = q->make_request_fn(q, bio);
|
|
|
|
blk_queue_exit(q);
|
|
|
|
bio = bio_list_pop(current->bio_list);
|
|
} else {
|
|
struct bio *bio_next = bio_list_pop(current->bio_list);
|
|
|
|
bio_io_error(bio);
|
|
bio = bio_next;
|
|
}
|
|
} while (bio);
|
|
current->bio_list = NULL; /* deactivate */
|
|
|
|
out:
|
|
return ret;
|
|
}
|
|
EXPORT_SYMBOL(generic_make_request);
|
|
|
|
/**
|
|
* submit_bio - submit a bio to the block device layer for I/O
|
|
* @bio: The &struct bio which describes the I/O
|
|
*
|
|
* submit_bio() is very similar in purpose to generic_make_request(), and
|
|
* uses that function to do most of the work. Both are fairly rough
|
|
* interfaces; @bio must be presetup and ready for I/O.
|
|
*
|
|
*/
|
|
blk_qc_t submit_bio(struct bio *bio)
|
|
{
|
|
/*
|
|
* If it's a regular read/write or a barrier with data attached,
|
|
* go through the normal accounting stuff before submission.
|
|
*/
|
|
if (bio_has_data(bio)) {
|
|
unsigned int count;
|
|
|
|
if (unlikely(bio_op(bio) == REQ_OP_WRITE_SAME))
|
|
count = bdev_logical_block_size(bio->bi_bdev) >> 9;
|
|
else
|
|
count = bio_sectors(bio);
|
|
|
|
if (op_is_write(bio_op(bio))) {
|
|
count_vm_events(PGPGOUT, count);
|
|
} else {
|
|
task_io_account_read(bio->bi_iter.bi_size);
|
|
count_vm_events(PGPGIN, count);
|
|
}
|
|
|
|
if (unlikely(block_dump)) {
|
|
char b[BDEVNAME_SIZE];
|
|
printk(KERN_DEBUG "%s(%d): %s block %Lu on %s (%u sectors)\n",
|
|
current->comm, task_pid_nr(current),
|
|
op_is_write(bio_op(bio)) ? "WRITE" : "READ",
|
|
(unsigned long long)bio->bi_iter.bi_sector,
|
|
bdevname(bio->bi_bdev, b),
|
|
count);
|
|
}
|
|
}
|
|
|
|
return generic_make_request(bio);
|
|
}
|
|
EXPORT_SYMBOL(submit_bio);
|
|
|
|
/**
|
|
* blk_cloned_rq_check_limits - Helper function to check a cloned request
|
|
* for new the queue limits
|
|
* @q: the queue
|
|
* @rq: the request being checked
|
|
*
|
|
* Description:
|
|
* @rq may have been made based on weaker limitations of upper-level queues
|
|
* in request stacking drivers, and it may violate the limitation of @q.
|
|
* Since the block layer and the underlying device driver trust @rq
|
|
* after it is inserted to @q, it should be checked against @q before
|
|
* the insertion using this generic function.
|
|
*
|
|
* Request stacking drivers like request-based dm may change the queue
|
|
* limits when retrying requests on other queues. Those requests need
|
|
* to be checked against the new queue limits again during dispatch.
|
|
*/
|
|
static int blk_cloned_rq_check_limits(struct request_queue *q,
|
|
struct request *rq)
|
|
{
|
|
if (blk_rq_sectors(rq) > blk_queue_get_max_sectors(q, req_op(rq))) {
|
|
printk(KERN_ERR "%s: over max size limit.\n", __func__);
|
|
return -EIO;
|
|
}
|
|
|
|
/*
|
|
* queue's settings related to segment counting like q->bounce_pfn
|
|
* may differ from that of other stacking queues.
|
|
* Recalculate it to check the request correctly on this queue's
|
|
* limitation.
|
|
*/
|
|
blk_recalc_rq_segments(rq);
|
|
if (rq->nr_phys_segments > queue_max_segments(q)) {
|
|
printk(KERN_ERR "%s: over max segments limit.\n", __func__);
|
|
return -EIO;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
/**
|
|
* blk_insert_cloned_request - Helper for stacking drivers to submit a request
|
|
* @q: the queue to submit the request
|
|
* @rq: the request being queued
|
|
*/
|
|
int blk_insert_cloned_request(struct request_queue *q, struct request *rq)
|
|
{
|
|
unsigned long flags;
|
|
int where = ELEVATOR_INSERT_BACK;
|
|
|
|
if (blk_cloned_rq_check_limits(q, rq))
|
|
return -EIO;
|
|
|
|
if (rq->rq_disk &&
|
|
should_fail_request(&rq->rq_disk->part0, blk_rq_bytes(rq)))
|
|
return -EIO;
|
|
|
|
if (q->mq_ops) {
|
|
if (blk_queue_io_stat(q))
|
|
blk_account_io_start(rq, true);
|
|
blk_mq_sched_insert_request(rq, false, true, false, false);
|
|
return 0;
|
|
}
|
|
|
|
spin_lock_irqsave(q->queue_lock, flags);
|
|
if (unlikely(blk_queue_dying(q))) {
|
|
spin_unlock_irqrestore(q->queue_lock, flags);
|
|
return -ENODEV;
|
|
}
|
|
|
|
/*
|
|
* Submitting request must be dequeued before calling this function
|
|
* because it will be linked to another request_queue
|
|
*/
|
|
BUG_ON(blk_queued_rq(rq));
|
|
|
|
if (op_is_flush(rq->cmd_flags))
|
|
where = ELEVATOR_INSERT_FLUSH;
|
|
|
|
add_acct_request(q, rq, where);
|
|
if (where == ELEVATOR_INSERT_FLUSH)
|
|
__blk_run_queue(q);
|
|
spin_unlock_irqrestore(q->queue_lock, flags);
|
|
|
|
return 0;
|
|
}
|
|
EXPORT_SYMBOL_GPL(blk_insert_cloned_request);
|
|
|
|
/**
|
|
* blk_rq_err_bytes - determine number of bytes till the next failure boundary
|
|
* @rq: request to examine
|
|
*
|
|
* Description:
|
|
* A request could be merge of IOs which require different failure
|
|
* handling. This function determines the number of bytes which
|
|
* can be failed from the beginning of the request without
|
|
* crossing into area which need to be retried further.
|
|
*
|
|
* Return:
|
|
* The number of bytes to fail.
|
|
*
|
|
* Context:
|
|
* queue_lock must be held.
|
|
*/
|
|
unsigned int blk_rq_err_bytes(const struct request *rq)
|
|
{
|
|
unsigned int ff = rq->cmd_flags & REQ_FAILFAST_MASK;
|
|
unsigned int bytes = 0;
|
|
struct bio *bio;
|
|
|
|
if (!(rq->rq_flags & RQF_MIXED_MERGE))
|
|
return blk_rq_bytes(rq);
|
|
|
|
/*
|
|
* Currently the only 'mixing' which can happen is between
|
|
* different fastfail types. We can safely fail portions
|
|
* which have all the failfast bits that the first one has -
|
|
* the ones which are at least as eager to fail as the first
|
|
* one.
|
|
*/
|
|
for (bio = rq->bio; bio; bio = bio->bi_next) {
|
|
if ((bio->bi_opf & ff) != ff)
|
|
break;
|
|
bytes += bio->bi_iter.bi_size;
|
|
}
|
|
|
|
/* this could lead to infinite loop */
|
|
BUG_ON(blk_rq_bytes(rq) && !bytes);
|
|
return bytes;
|
|
}
|
|
EXPORT_SYMBOL_GPL(blk_rq_err_bytes);
|
|
|
|
void blk_account_io_completion(struct request *req, unsigned int bytes)
|
|
{
|
|
if (blk_do_io_stat(req)) {
|
|
const int rw = rq_data_dir(req);
|
|
struct hd_struct *part;
|
|
int cpu;
|
|
|
|
cpu = part_stat_lock();
|
|
part = req->part;
|
|
part_stat_add(cpu, part, sectors[rw], bytes >> 9);
|
|
part_stat_unlock();
|
|
}
|
|
}
|
|
|
|
void blk_account_io_done(struct request *req)
|
|
{
|
|
/*
|
|
* Account IO completion. flush_rq isn't accounted as a
|
|
* normal IO on queueing nor completion. Accounting the
|
|
* containing request is enough.
|
|
*/
|
|
if (blk_do_io_stat(req) && !(req->rq_flags & RQF_FLUSH_SEQ)) {
|
|
unsigned long duration = jiffies - req->start_time;
|
|
const int rw = rq_data_dir(req);
|
|
struct hd_struct *part;
|
|
int cpu;
|
|
|
|
cpu = part_stat_lock();
|
|
part = req->part;
|
|
|
|
part_stat_inc(cpu, part, ios[rw]);
|
|
part_stat_add(cpu, part, ticks[rw], duration);
|
|
part_round_stats(cpu, part);
|
|
part_dec_in_flight(part, rw);
|
|
|
|
hd_struct_put(part);
|
|
part_stat_unlock();
|
|
}
|
|
}
|
|
|
|
#ifdef CONFIG_PM
|
|
/*
|
|
* Don't process normal requests when queue is suspended
|
|
* or in the process of suspending/resuming
|
|
*/
|
|
static struct request *blk_pm_peek_request(struct request_queue *q,
|
|
struct request *rq)
|
|
{
|
|
if (q->dev && (q->rpm_status == RPM_SUSPENDED ||
|
|
(q->rpm_status != RPM_ACTIVE && !(rq->rq_flags & RQF_PM))))
|
|
return NULL;
|
|
else
|
|
return rq;
|
|
}
|
|
#else
|
|
static inline struct request *blk_pm_peek_request(struct request_queue *q,
|
|
struct request *rq)
|
|
{
|
|
return rq;
|
|
}
|
|
#endif
|
|
|
|
void blk_account_io_start(struct request *rq, bool new_io)
|
|
{
|
|
struct hd_struct *part;
|
|
int rw = rq_data_dir(rq);
|
|
int cpu;
|
|
|
|
if (!blk_do_io_stat(rq))
|
|
return;
|
|
|
|
cpu = part_stat_lock();
|
|
|
|
if (!new_io) {
|
|
part = rq->part;
|
|
part_stat_inc(cpu, part, merges[rw]);
|
|
} else {
|
|
part = disk_map_sector_rcu(rq->rq_disk, blk_rq_pos(rq));
|
|
if (!hd_struct_try_get(part)) {
|
|
/*
|
|
* The partition is already being removed,
|
|
* the request will be accounted on the disk only
|
|
*
|
|
* We take a reference on disk->part0 although that
|
|
* partition will never be deleted, so we can treat
|
|
* it as any other partition.
|
|
*/
|
|
part = &rq->rq_disk->part0;
|
|
hd_struct_get(part);
|
|
}
|
|
part_round_stats(cpu, part);
|
|
part_inc_in_flight(part, rw);
|
|
rq->part = part;
|
|
}
|
|
|
|
part_stat_unlock();
|
|
}
|
|
|
|
/**
|
|
* blk_peek_request - peek at the top of a request queue
|
|
* @q: request queue to peek at
|
|
*
|
|
* Description:
|
|
* Return the request at the top of @q. The returned request
|
|
* should be started using blk_start_request() before LLD starts
|
|
* processing it.
|
|
*
|
|
* Return:
|
|
* Pointer to the request at the top of @q if available. Null
|
|
* otherwise.
|
|
*
|
|
* Context:
|
|
* queue_lock must be held.
|
|
*/
|
|
struct request *blk_peek_request(struct request_queue *q)
|
|
{
|
|
struct request *rq;
|
|
int ret;
|
|
|
|
while ((rq = __elv_next_request(q)) != NULL) {
|
|
|
|
rq = blk_pm_peek_request(q, rq);
|
|
if (!rq)
|
|
break;
|
|
|
|
if (!(rq->rq_flags & RQF_STARTED)) {
|
|
/*
|
|
* This is the first time the device driver
|
|
* sees this request (possibly after
|
|
* requeueing). Notify IO scheduler.
|
|
*/
|
|
if (rq->rq_flags & RQF_SORTED)
|
|
elv_activate_rq(q, rq);
|
|
|
|
/*
|
|
* just mark as started even if we don't start
|
|
* it, a request that has been delayed should
|
|
* not be passed by new incoming requests
|
|
*/
|
|
rq->rq_flags |= RQF_STARTED;
|
|
trace_block_rq_issue(q, rq);
|
|
}
|
|
|
|
if (!q->boundary_rq || q->boundary_rq == rq) {
|
|
q->end_sector = rq_end_sector(rq);
|
|
q->boundary_rq = NULL;
|
|
}
|
|
|
|
if (rq->rq_flags & RQF_DONTPREP)
|
|
break;
|
|
|
|
if (q->dma_drain_size && blk_rq_bytes(rq)) {
|
|
/*
|
|
* make sure space for the drain appears we
|
|
* know we can do this because max_hw_segments
|
|
* has been adjusted to be one fewer than the
|
|
* device can handle
|
|
*/
|
|
rq->nr_phys_segments++;
|
|
}
|
|
|
|
if (!q->prep_rq_fn)
|
|
break;
|
|
|
|
ret = q->prep_rq_fn(q, rq);
|
|
if (ret == BLKPREP_OK) {
|
|
break;
|
|
} else if (ret == BLKPREP_DEFER) {
|
|
/*
|
|
* the request may have been (partially) prepped.
|
|
* we need to keep this request in the front to
|
|
* avoid resource deadlock. RQF_STARTED will
|
|
* prevent other fs requests from passing this one.
|
|
*/
|
|
if (q->dma_drain_size && blk_rq_bytes(rq) &&
|
|
!(rq->rq_flags & RQF_DONTPREP)) {
|
|
/*
|
|
* remove the space for the drain we added
|
|
* so that we don't add it again
|
|
*/
|
|
--rq->nr_phys_segments;
|
|
}
|
|
|
|
rq = NULL;
|
|
break;
|
|
} else if (ret == BLKPREP_KILL || ret == BLKPREP_INVALID) {
|
|
int err = (ret == BLKPREP_INVALID) ? -EREMOTEIO : -EIO;
|
|
|
|
rq->rq_flags |= RQF_QUIET;
|
|
/*
|
|
* Mark this request as started so we don't trigger
|
|
* any debug logic in the end I/O path.
|
|
*/
|
|
blk_start_request(rq);
|
|
__blk_end_request_all(rq, err);
|
|
} else {
|
|
printk(KERN_ERR "%s: bad return=%d\n", __func__, ret);
|
|
break;
|
|
}
|
|
}
|
|
|
|
return rq;
|
|
}
|
|
EXPORT_SYMBOL(blk_peek_request);
|
|
|
|
void blk_dequeue_request(struct request *rq)
|
|
{
|
|
struct request_queue *q = rq->q;
|
|
|
|
BUG_ON(list_empty(&rq->queuelist));
|
|
BUG_ON(ELV_ON_HASH(rq));
|
|
|
|
list_del_init(&rq->queuelist);
|
|
|
|
/*
|
|
* the time frame between a request being removed from the lists
|
|
* and to it is freed is accounted as io that is in progress at
|
|
* the driver side.
|
|
*/
|
|
if (blk_account_rq(rq)) {
|
|
q->in_flight[rq_is_sync(rq)]++;
|
|
set_io_start_time_ns(rq);
|
|
}
|
|
}
|
|
|
|
/**
|
|
* blk_start_request - start request processing on the driver
|
|
* @req: request to dequeue
|
|
*
|
|
* Description:
|
|
* Dequeue @req and start timeout timer on it. This hands off the
|
|
* request to the driver.
|
|
*
|
|
* Block internal functions which don't want to start timer should
|
|
* call blk_dequeue_request().
|
|
*
|
|
* Context:
|
|
* queue_lock must be held.
|
|
*/
|
|
void blk_start_request(struct request *req)
|
|
{
|
|
blk_dequeue_request(req);
|
|
|
|
if (test_bit(QUEUE_FLAG_STATS, &req->q->queue_flags)) {
|
|
blk_stat_set_issue_time(&req->issue_stat);
|
|
req->rq_flags |= RQF_STATS;
|
|
wbt_issue(req->q->rq_wb, &req->issue_stat);
|
|
}
|
|
|
|
/*
|
|
* We are now handing the request to the hardware, initialize
|
|
* resid_len to full count and add the timeout handler.
|
|
*/
|
|
req->resid_len = blk_rq_bytes(req);
|
|
if (unlikely(blk_bidi_rq(req)))
|
|
req->next_rq->resid_len = blk_rq_bytes(req->next_rq);
|
|
|
|
BUG_ON(test_bit(REQ_ATOM_COMPLETE, &req->atomic_flags));
|
|
blk_add_timer(req);
|
|
}
|
|
EXPORT_SYMBOL(blk_start_request);
|
|
|
|
/**
|
|
* blk_fetch_request - fetch a request from a request queue
|
|
* @q: request queue to fetch a request from
|
|
*
|
|
* Description:
|
|
* Return the request at the top of @q. The request is started on
|
|
* return and LLD can start processing it immediately.
|
|
*
|
|
* Return:
|
|
* Pointer to the request at the top of @q if available. Null
|
|
* otherwise.
|
|
*
|
|
* Context:
|
|
* queue_lock must be held.
|
|
*/
|
|
struct request *blk_fetch_request(struct request_queue *q)
|
|
{
|
|
struct request *rq;
|
|
|
|
rq = blk_peek_request(q);
|
|
if (rq)
|
|
blk_start_request(rq);
|
|
return rq;
|
|
}
|
|
EXPORT_SYMBOL(blk_fetch_request);
|
|
|
|
/**
|
|
* blk_update_request - Special helper function for request stacking drivers
|
|
* @req: the request being processed
|
|
* @error: %0 for success, < %0 for error
|
|
* @nr_bytes: number of bytes to complete @req
|
|
*
|
|
* Description:
|
|
* Ends I/O on a number of bytes attached to @req, but doesn't complete
|
|
* the request structure even if @req doesn't have leftover.
|
|
* If @req has leftover, sets it up for the next range of segments.
|
|
*
|
|
* This special helper function is only for request stacking drivers
|
|
* (e.g. request-based dm) so that they can handle partial completion.
|
|
* Actual device drivers should use blk_end_request instead.
|
|
*
|
|
* Passing the result of blk_rq_bytes() as @nr_bytes guarantees
|
|
* %false return from this function.
|
|
*
|
|
* Return:
|
|
* %false - this request doesn't have any more data
|
|
* %true - this request has more data
|
|
**/
|
|
bool blk_update_request(struct request *req, int error, unsigned int nr_bytes)
|
|
{
|
|
int total_bytes;
|
|
|
|
trace_block_rq_complete(req->q, req, nr_bytes);
|
|
|
|
if (!req->bio)
|
|
return false;
|
|
|
|
/*
|
|
* For fs requests, rq is just carrier of independent bio's
|
|
* and each partial completion should be handled separately.
|
|
* Reset per-request error on each partial completion.
|
|
*
|
|
* TODO: tj: This is too subtle. It would be better to let
|
|
* low level drivers do what they see fit.
|
|
*/
|
|
if (req->cmd_type == REQ_TYPE_FS)
|
|
req->errors = 0;
|
|
|
|
if (error && req->cmd_type == REQ_TYPE_FS &&
|
|
!(req->rq_flags & RQF_QUIET)) {
|
|
char *error_type;
|
|
|
|
switch (error) {
|
|
case -ENOLINK:
|
|
error_type = "recoverable transport";
|
|
break;
|
|
case -EREMOTEIO:
|
|
error_type = "critical target";
|
|
break;
|
|
case -EBADE:
|
|
error_type = "critical nexus";
|
|
break;
|
|
case -ETIMEDOUT:
|
|
error_type = "timeout";
|
|
break;
|
|
case -ENOSPC:
|
|
error_type = "critical space allocation";
|
|
break;
|
|
case -ENODATA:
|
|
error_type = "critical medium";
|
|
break;
|
|
case -EIO:
|
|
default:
|
|
error_type = "I/O";
|
|
break;
|
|
}
|
|
printk_ratelimited(KERN_ERR "%s: %s error, dev %s, sector %llu\n",
|
|
__func__, error_type, req->rq_disk ?
|
|
req->rq_disk->disk_name : "?",
|
|
(unsigned long long)blk_rq_pos(req));
|
|
|
|
}
|
|
|
|
blk_account_io_completion(req, nr_bytes);
|
|
|
|
total_bytes = 0;
|
|
while (req->bio) {
|
|
struct bio *bio = req->bio;
|
|
unsigned bio_bytes = min(bio->bi_iter.bi_size, nr_bytes);
|
|
|
|
if (bio_bytes == bio->bi_iter.bi_size)
|
|
req->bio = bio->bi_next;
|
|
|
|
req_bio_endio(req, bio, bio_bytes, error);
|
|
|
|
total_bytes += bio_bytes;
|
|
nr_bytes -= bio_bytes;
|
|
|
|
if (!nr_bytes)
|
|
break;
|
|
}
|
|
|
|
/*
|
|
* completely done
|
|
*/
|
|
if (!req->bio) {
|
|
/*
|
|
* Reset counters so that the request stacking driver
|
|
* can find how many bytes remain in the request
|
|
* later.
|
|
*/
|
|
req->__data_len = 0;
|
|
return false;
|
|
}
|
|
|
|
WARN_ON_ONCE(req->rq_flags & RQF_SPECIAL_PAYLOAD);
|
|
|
|
req->__data_len -= total_bytes;
|
|
|
|
/* update sector only for requests with clear definition of sector */
|
|
if (req->cmd_type == REQ_TYPE_FS)
|
|
req->__sector += total_bytes >> 9;
|
|
|
|
/* mixed attributes always follow the first bio */
|
|
if (req->rq_flags & RQF_MIXED_MERGE) {
|
|
req->cmd_flags &= ~REQ_FAILFAST_MASK;
|
|
req->cmd_flags |= req->bio->bi_opf & REQ_FAILFAST_MASK;
|
|
}
|
|
|
|
/*
|
|
* If total number of sectors is less than the first segment
|
|
* size, something has gone terribly wrong.
|
|
*/
|
|
if (blk_rq_bytes(req) < blk_rq_cur_bytes(req)) {
|
|
blk_dump_rq_flags(req, "request botched");
|
|
req->__data_len = blk_rq_cur_bytes(req);
|
|
}
|
|
|
|
/* recalculate the number of segments */
|
|
blk_recalc_rq_segments(req);
|
|
|
|
return true;
|
|
}
|
|
EXPORT_SYMBOL_GPL(blk_update_request);
|
|
|
|
static bool blk_update_bidi_request(struct request *rq, int error,
|
|
unsigned int nr_bytes,
|
|
unsigned int bidi_bytes)
|
|
{
|
|
if (blk_update_request(rq, error, nr_bytes))
|
|
return true;
|
|
|
|
/* Bidi request must be completed as a whole */
|
|
if (unlikely(blk_bidi_rq(rq)) &&
|
|
blk_update_request(rq->next_rq, error, bidi_bytes))
|
|
return true;
|
|
|
|
if (blk_queue_add_random(rq->q))
|
|
add_disk_randomness(rq->rq_disk);
|
|
|
|
return false;
|
|
}
|
|
|
|
/**
|
|
* blk_unprep_request - unprepare a request
|
|
* @req: the request
|
|
*
|
|
* This function makes a request ready for complete resubmission (or
|
|
* completion). It happens only after all error handling is complete,
|
|
* so represents the appropriate moment to deallocate any resources
|
|
* that were allocated to the request in the prep_rq_fn. The queue
|
|
* lock is held when calling this.
|
|
*/
|
|
void blk_unprep_request(struct request *req)
|
|
{
|
|
struct request_queue *q = req->q;
|
|
|
|
req->rq_flags &= ~RQF_DONTPREP;
|
|
if (q->unprep_rq_fn)
|
|
q->unprep_rq_fn(q, req);
|
|
}
|
|
EXPORT_SYMBOL_GPL(blk_unprep_request);
|
|
|
|
/*
|
|
* queue lock must be held
|
|
*/
|
|
void blk_finish_request(struct request *req, int error)
|
|
{
|
|
struct request_queue *q = req->q;
|
|
|
|
if (req->rq_flags & RQF_STATS)
|
|
blk_stat_add(&q->rq_stats[rq_data_dir(req)], req);
|
|
|
|
if (req->rq_flags & RQF_QUEUED)
|
|
blk_queue_end_tag(q, req);
|
|
|
|
BUG_ON(blk_queued_rq(req));
|
|
|
|
if (unlikely(laptop_mode) && req->cmd_type == REQ_TYPE_FS)
|
|
laptop_io_completion(&req->q->backing_dev_info);
|
|
|
|
blk_delete_timer(req);
|
|
|
|
if (req->rq_flags & RQF_DONTPREP)
|
|
blk_unprep_request(req);
|
|
|
|
blk_account_io_done(req);
|
|
|
|
if (req->end_io) {
|
|
wbt_done(req->q->rq_wb, &req->issue_stat);
|
|
req->end_io(req, error);
|
|
} else {
|
|
if (blk_bidi_rq(req))
|
|
__blk_put_request(req->next_rq->q, req->next_rq);
|
|
|
|
__blk_put_request(q, req);
|
|
}
|
|
}
|
|
EXPORT_SYMBOL(blk_finish_request);
|
|
|
|
/**
|
|
* blk_end_bidi_request - Complete a bidi request
|
|
* @rq: the request to complete
|
|
* @error: %0 for success, < %0 for error
|
|
* @nr_bytes: number of bytes to complete @rq
|
|
* @bidi_bytes: number of bytes to complete @rq->next_rq
|
|
*
|
|
* Description:
|
|
* Ends I/O on a number of bytes attached to @rq and @rq->next_rq.
|
|
* Drivers that supports bidi can safely call this member for any
|
|
* type of request, bidi or uni. In the later case @bidi_bytes is
|
|
* just ignored.
|
|
*
|
|
* Return:
|
|
* %false - we are done with this request
|
|
* %true - still buffers pending for this request
|
|
**/
|
|
static bool blk_end_bidi_request(struct request *rq, int error,
|
|
unsigned int nr_bytes, unsigned int bidi_bytes)
|
|
{
|
|
struct request_queue *q = rq->q;
|
|
unsigned long flags;
|
|
|
|
if (blk_update_bidi_request(rq, error, nr_bytes, bidi_bytes))
|
|
return true;
|
|
|
|
spin_lock_irqsave(q->queue_lock, flags);
|
|
blk_finish_request(rq, error);
|
|
spin_unlock_irqrestore(q->queue_lock, flags);
|
|
|
|
return false;
|
|
}
|
|
|
|
/**
|
|
* __blk_end_bidi_request - Complete a bidi request with queue lock held
|
|
* @rq: the request to complete
|
|
* @error: %0 for success, < %0 for error
|
|
* @nr_bytes: number of bytes to complete @rq
|
|
* @bidi_bytes: number of bytes to complete @rq->next_rq
|
|
*
|
|
* Description:
|
|
* Identical to blk_end_bidi_request() except that queue lock is
|
|
* assumed to be locked on entry and remains so on return.
|
|
*
|
|
* Return:
|
|
* %false - we are done with this request
|
|
* %true - still buffers pending for this request
|
|
**/
|
|
bool __blk_end_bidi_request(struct request *rq, int error,
|
|
unsigned int nr_bytes, unsigned int bidi_bytes)
|
|
{
|
|
if (blk_update_bidi_request(rq, error, nr_bytes, bidi_bytes))
|
|
return true;
|
|
|
|
blk_finish_request(rq, error);
|
|
|
|
return false;
|
|
}
|
|
|
|
/**
|
|
* blk_end_request - Helper function for drivers to complete the request.
|
|
* @rq: the request being processed
|
|
* @error: %0 for success, < %0 for error
|
|
* @nr_bytes: number of bytes to complete
|
|
*
|
|
* Description:
|
|
* Ends I/O on a number of bytes attached to @rq.
|
|
* If @rq has leftover, sets it up for the next range of segments.
|
|
*
|
|
* Return:
|
|
* %false - we are done with this request
|
|
* %true - still buffers pending for this request
|
|
**/
|
|
bool blk_end_request(struct request *rq, int error, unsigned int nr_bytes)
|
|
{
|
|
return blk_end_bidi_request(rq, error, nr_bytes, 0);
|
|
}
|
|
EXPORT_SYMBOL(blk_end_request);
|
|
|
|
/**
|
|
* blk_end_request_all - Helper function for drives to finish the request.
|
|
* @rq: the request to finish
|
|
* @error: %0 for success, < %0 for error
|
|
*
|
|
* Description:
|
|
* Completely finish @rq.
|
|
*/
|
|
void blk_end_request_all(struct request *rq, int error)
|
|
{
|
|
bool pending;
|
|
unsigned int bidi_bytes = 0;
|
|
|
|
if (unlikely(blk_bidi_rq(rq)))
|
|
bidi_bytes = blk_rq_bytes(rq->next_rq);
|
|
|
|
pending = blk_end_bidi_request(rq, error, blk_rq_bytes(rq), bidi_bytes);
|
|
BUG_ON(pending);
|
|
}
|
|
EXPORT_SYMBOL(blk_end_request_all);
|
|
|
|
/**
|
|
* blk_end_request_cur - Helper function to finish the current request chunk.
|
|
* @rq: the request to finish the current chunk for
|
|
* @error: %0 for success, < %0 for error
|
|
*
|
|
* Description:
|
|
* Complete the current consecutively mapped chunk from @rq.
|
|
*
|
|
* Return:
|
|
* %false - we are done with this request
|
|
* %true - still buffers pending for this request
|
|
*/
|
|
bool blk_end_request_cur(struct request *rq, int error)
|
|
{
|
|
return blk_end_request(rq, error, blk_rq_cur_bytes(rq));
|
|
}
|
|
EXPORT_SYMBOL(blk_end_request_cur);
|
|
|
|
/**
|
|
* blk_end_request_err - Finish a request till the next failure boundary.
|
|
* @rq: the request to finish till the next failure boundary for
|
|
* @error: must be negative errno
|
|
*
|
|
* Description:
|
|
* Complete @rq till the next failure boundary.
|
|
*
|
|
* Return:
|
|
* %false - we are done with this request
|
|
* %true - still buffers pending for this request
|
|
*/
|
|
bool blk_end_request_err(struct request *rq, int error)
|
|
{
|
|
WARN_ON(error >= 0);
|
|
return blk_end_request(rq, error, blk_rq_err_bytes(rq));
|
|
}
|
|
EXPORT_SYMBOL_GPL(blk_end_request_err);
|
|
|
|
/**
|
|
* __blk_end_request - Helper function for drivers to complete the request.
|
|
* @rq: the request being processed
|
|
* @error: %0 for success, < %0 for error
|
|
* @nr_bytes: number of bytes to complete
|
|
*
|
|
* Description:
|
|
* Must be called with queue lock held unlike blk_end_request().
|
|
*
|
|
* Return:
|
|
* %false - we are done with this request
|
|
* %true - still buffers pending for this request
|
|
**/
|
|
bool __blk_end_request(struct request *rq, int error, unsigned int nr_bytes)
|
|
{
|
|
return __blk_end_bidi_request(rq, error, nr_bytes, 0);
|
|
}
|
|
EXPORT_SYMBOL(__blk_end_request);
|
|
|
|
/**
|
|
* __blk_end_request_all - Helper function for drives to finish the request.
|
|
* @rq: the request to finish
|
|
* @error: %0 for success, < %0 for error
|
|
*
|
|
* Description:
|
|
* Completely finish @rq. Must be called with queue lock held.
|
|
*/
|
|
void __blk_end_request_all(struct request *rq, int error)
|
|
{
|
|
bool pending;
|
|
unsigned int bidi_bytes = 0;
|
|
|
|
if (unlikely(blk_bidi_rq(rq)))
|
|
bidi_bytes = blk_rq_bytes(rq->next_rq);
|
|
|
|
pending = __blk_end_bidi_request(rq, error, blk_rq_bytes(rq), bidi_bytes);
|
|
BUG_ON(pending);
|
|
}
|
|
EXPORT_SYMBOL(__blk_end_request_all);
|
|
|
|
/**
|
|
* __blk_end_request_cur - Helper function to finish the current request chunk.
|
|
* @rq: the request to finish the current chunk for
|
|
* @error: %0 for success, < %0 for error
|
|
*
|
|
* Description:
|
|
* Complete the current consecutively mapped chunk from @rq. Must
|
|
* be called with queue lock held.
|
|
*
|
|
* Return:
|
|
* %false - we are done with this request
|
|
* %true - still buffers pending for this request
|
|
*/
|
|
bool __blk_end_request_cur(struct request *rq, int error)
|
|
{
|
|
return __blk_end_request(rq, error, blk_rq_cur_bytes(rq));
|
|
}
|
|
EXPORT_SYMBOL(__blk_end_request_cur);
|
|
|
|
/**
|
|
* __blk_end_request_err - Finish a request till the next failure boundary.
|
|
* @rq: the request to finish till the next failure boundary for
|
|
* @error: must be negative errno
|
|
*
|
|
* Description:
|
|
* Complete @rq till the next failure boundary. Must be called
|
|
* with queue lock held.
|
|
*
|
|
* Return:
|
|
* %false - we are done with this request
|
|
* %true - still buffers pending for this request
|
|
*/
|
|
bool __blk_end_request_err(struct request *rq, int error)
|
|
{
|
|
WARN_ON(error >= 0);
|
|
return __blk_end_request(rq, error, blk_rq_err_bytes(rq));
|
|
}
|
|
EXPORT_SYMBOL_GPL(__blk_end_request_err);
|
|
|
|
void blk_rq_bio_prep(struct request_queue *q, struct request *rq,
|
|
struct bio *bio)
|
|
{
|
|
if (bio_has_data(bio))
|
|
rq->nr_phys_segments = bio_phys_segments(q, bio);
|
|
|
|
rq->__data_len = bio->bi_iter.bi_size;
|
|
rq->bio = rq->biotail = bio;
|
|
|
|
if (bio->bi_bdev)
|
|
rq->rq_disk = bio->bi_bdev->bd_disk;
|
|
}
|
|
|
|
#if ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE
|
|
/**
|
|
* rq_flush_dcache_pages - Helper function to flush all pages in a request
|
|
* @rq: the request to be flushed
|
|
*
|
|
* Description:
|
|
* Flush all pages in @rq.
|
|
*/
|
|
void rq_flush_dcache_pages(struct request *rq)
|
|
{
|
|
struct req_iterator iter;
|
|
struct bio_vec bvec;
|
|
|
|
rq_for_each_segment(bvec, rq, iter)
|
|
flush_dcache_page(bvec.bv_page);
|
|
}
|
|
EXPORT_SYMBOL_GPL(rq_flush_dcache_pages);
|
|
#endif
|
|
|
|
/**
|
|
* blk_lld_busy - Check if underlying low-level drivers of a device are busy
|
|
* @q : the queue of the device being checked
|
|
*
|
|
* Description:
|
|
* Check if underlying low-level drivers of a device are busy.
|
|
* If the drivers want to export their busy state, they must set own
|
|
* exporting function using blk_queue_lld_busy() first.
|
|
*
|
|
* Basically, this function is used only by request stacking drivers
|
|
* to stop dispatching requests to underlying devices when underlying
|
|
* devices are busy. This behavior helps more I/O merging on the queue
|
|
* of the request stacking driver and prevents I/O throughput regression
|
|
* on burst I/O load.
|
|
*
|
|
* Return:
|
|
* 0 - Not busy (The request stacking driver should dispatch request)
|
|
* 1 - Busy (The request stacking driver should stop dispatching request)
|
|
*/
|
|
int blk_lld_busy(struct request_queue *q)
|
|
{
|
|
if (q->lld_busy_fn)
|
|
return q->lld_busy_fn(q);
|
|
|
|
return 0;
|
|
}
|
|
EXPORT_SYMBOL_GPL(blk_lld_busy);
|
|
|
|
/**
|
|
* blk_rq_unprep_clone - Helper function to free all bios in a cloned request
|
|
* @rq: the clone request to be cleaned up
|
|
*
|
|
* Description:
|
|
* Free all bios in @rq for a cloned request.
|
|
*/
|
|
void blk_rq_unprep_clone(struct request *rq)
|
|
{
|
|
struct bio *bio;
|
|
|
|
while ((bio = rq->bio) != NULL) {
|
|
rq->bio = bio->bi_next;
|
|
|
|
bio_put(bio);
|
|
}
|
|
}
|
|
EXPORT_SYMBOL_GPL(blk_rq_unprep_clone);
|
|
|
|
/*
|
|
* Copy attributes of the original request to the clone request.
|
|
* The actual data parts (e.g. ->cmd, ->sense) are not copied.
|
|
*/
|
|
static void __blk_rq_prep_clone(struct request *dst, struct request *src)
|
|
{
|
|
dst->cpu = src->cpu;
|
|
dst->cmd_flags = src->cmd_flags | REQ_NOMERGE;
|
|
dst->cmd_type = src->cmd_type;
|
|
dst->__sector = blk_rq_pos(src);
|
|
dst->__data_len = blk_rq_bytes(src);
|
|
dst->nr_phys_segments = src->nr_phys_segments;
|
|
dst->ioprio = src->ioprio;
|
|
dst->extra_len = src->extra_len;
|
|
}
|
|
|
|
/**
|
|
* blk_rq_prep_clone - Helper function to setup clone request
|
|
* @rq: the request to be setup
|
|
* @rq_src: original request to be cloned
|
|
* @bs: bio_set that bios for clone are allocated from
|
|
* @gfp_mask: memory allocation mask for bio
|
|
* @bio_ctr: setup function to be called for each clone bio.
|
|
* Returns %0 for success, non %0 for failure.
|
|
* @data: private data to be passed to @bio_ctr
|
|
*
|
|
* Description:
|
|
* Clones bios in @rq_src to @rq, and copies attributes of @rq_src to @rq.
|
|
* The actual data parts of @rq_src (e.g. ->cmd, ->sense)
|
|
* are not copied, and copying such parts is the caller's responsibility.
|
|
* Also, pages which the original bios are pointing to are not copied
|
|
* and the cloned bios just point same pages.
|
|
* So cloned bios must be completed before original bios, which means
|
|
* the caller must complete @rq before @rq_src.
|
|
*/
|
|
int blk_rq_prep_clone(struct request *rq, struct request *rq_src,
|
|
struct bio_set *bs, gfp_t gfp_mask,
|
|
int (*bio_ctr)(struct bio *, struct bio *, void *),
|
|
void *data)
|
|
{
|
|
struct bio *bio, *bio_src;
|
|
|
|
if (!bs)
|
|
bs = fs_bio_set;
|
|
|
|
__rq_for_each_bio(bio_src, rq_src) {
|
|
bio = bio_clone_fast(bio_src, gfp_mask, bs);
|
|
if (!bio)
|
|
goto free_and_out;
|
|
|
|
if (bio_ctr && bio_ctr(bio, bio_src, data))
|
|
goto free_and_out;
|
|
|
|
if (rq->bio) {
|
|
rq->biotail->bi_next = bio;
|
|
rq->biotail = bio;
|
|
} else
|
|
rq->bio = rq->biotail = bio;
|
|
}
|
|
|
|
__blk_rq_prep_clone(rq, rq_src);
|
|
|
|
return 0;
|
|
|
|
free_and_out:
|
|
if (bio)
|
|
bio_put(bio);
|
|
blk_rq_unprep_clone(rq);
|
|
|
|
return -ENOMEM;
|
|
}
|
|
EXPORT_SYMBOL_GPL(blk_rq_prep_clone);
|
|
|
|
int kblockd_schedule_work(struct work_struct *work)
|
|
{
|
|
return queue_work(kblockd_workqueue, work);
|
|
}
|
|
EXPORT_SYMBOL(kblockd_schedule_work);
|
|
|
|
int kblockd_schedule_work_on(int cpu, struct work_struct *work)
|
|
{
|
|
return queue_work_on(cpu, kblockd_workqueue, work);
|
|
}
|
|
EXPORT_SYMBOL(kblockd_schedule_work_on);
|
|
|
|
int kblockd_schedule_delayed_work(struct delayed_work *dwork,
|
|
unsigned long delay)
|
|
{
|
|
return queue_delayed_work(kblockd_workqueue, dwork, delay);
|
|
}
|
|
EXPORT_SYMBOL(kblockd_schedule_delayed_work);
|
|
|
|
int kblockd_schedule_delayed_work_on(int cpu, struct delayed_work *dwork,
|
|
unsigned long delay)
|
|
{
|
|
return queue_delayed_work_on(cpu, kblockd_workqueue, dwork, delay);
|
|
}
|
|
EXPORT_SYMBOL(kblockd_schedule_delayed_work_on);
|
|
|
|
/**
|
|
* blk_start_plug - initialize blk_plug and track it inside the task_struct
|
|
* @plug: The &struct blk_plug that needs to be initialized
|
|
*
|
|
* Description:
|
|
* Tracking blk_plug inside the task_struct will help with auto-flushing the
|
|
* pending I/O should the task end up blocking between blk_start_plug() and
|
|
* blk_finish_plug(). This is important from a performance perspective, but
|
|
* also ensures that we don't deadlock. For instance, if the task is blocking
|
|
* for a memory allocation, memory reclaim could end up wanting to free a
|
|
* page belonging to that request that is currently residing in our private
|
|
* plug. By flushing the pending I/O when the process goes to sleep, we avoid
|
|
* this kind of deadlock.
|
|
*/
|
|
void blk_start_plug(struct blk_plug *plug)
|
|
{
|
|
struct task_struct *tsk = current;
|
|
|
|
/*
|
|
* If this is a nested plug, don't actually assign it.
|
|
*/
|
|
if (tsk->plug)
|
|
return;
|
|
|
|
INIT_LIST_HEAD(&plug->list);
|
|
INIT_LIST_HEAD(&plug->mq_list);
|
|
INIT_LIST_HEAD(&plug->cb_list);
|
|
/*
|
|
* Store ordering should not be needed here, since a potential
|
|
* preempt will imply a full memory barrier
|
|
*/
|
|
tsk->plug = plug;
|
|
}
|
|
EXPORT_SYMBOL(blk_start_plug);
|
|
|
|
static int plug_rq_cmp(void *priv, struct list_head *a, struct list_head *b)
|
|
{
|
|
struct request *rqa = container_of(a, struct request, queuelist);
|
|
struct request *rqb = container_of(b, struct request, queuelist);
|
|
|
|
return !(rqa->q < rqb->q ||
|
|
(rqa->q == rqb->q && blk_rq_pos(rqa) < blk_rq_pos(rqb)));
|
|
}
|
|
|
|
/*
|
|
* If 'from_schedule' is true, then postpone the dispatch of requests
|
|
* until a safe kblockd context. We due this to avoid accidental big
|
|
* additional stack usage in driver dispatch, in places where the originally
|
|
* plugger did not intend it.
|
|
*/
|
|
static void queue_unplugged(struct request_queue *q, unsigned int depth,
|
|
bool from_schedule)
|
|
__releases(q->queue_lock)
|
|
{
|
|
trace_block_unplug(q, depth, !from_schedule);
|
|
|
|
if (from_schedule)
|
|
blk_run_queue_async(q);
|
|
else
|
|
__blk_run_queue(q);
|
|
spin_unlock(q->queue_lock);
|
|
}
|
|
|
|
static void flush_plug_callbacks(struct blk_plug *plug, bool from_schedule)
|
|
{
|
|
LIST_HEAD(callbacks);
|
|
|
|
while (!list_empty(&plug->cb_list)) {
|
|
list_splice_init(&plug->cb_list, &callbacks);
|
|
|
|
while (!list_empty(&callbacks)) {
|
|
struct blk_plug_cb *cb = list_first_entry(&callbacks,
|
|
struct blk_plug_cb,
|
|
list);
|
|
list_del(&cb->list);
|
|
cb->callback(cb, from_schedule);
|
|
}
|
|
}
|
|
}
|
|
|
|
struct blk_plug_cb *blk_check_plugged(blk_plug_cb_fn unplug, void *data,
|
|
int size)
|
|
{
|
|
struct blk_plug *plug = current->plug;
|
|
struct blk_plug_cb *cb;
|
|
|
|
if (!plug)
|
|
return NULL;
|
|
|
|
list_for_each_entry(cb, &plug->cb_list, list)
|
|
if (cb->callback == unplug && cb->data == data)
|
|
return cb;
|
|
|
|
/* Not currently on the callback list */
|
|
BUG_ON(size < sizeof(*cb));
|
|
cb = kzalloc(size, GFP_ATOMIC);
|
|
if (cb) {
|
|
cb->data = data;
|
|
cb->callback = unplug;
|
|
list_add(&cb->list, &plug->cb_list);
|
|
}
|
|
return cb;
|
|
}
|
|
EXPORT_SYMBOL(blk_check_plugged);
|
|
|
|
void blk_flush_plug_list(struct blk_plug *plug, bool from_schedule)
|
|
{
|
|
struct request_queue *q;
|
|
unsigned long flags;
|
|
struct request *rq;
|
|
LIST_HEAD(list);
|
|
unsigned int depth;
|
|
|
|
flush_plug_callbacks(plug, from_schedule);
|
|
|
|
if (!list_empty(&plug->mq_list))
|
|
blk_mq_flush_plug_list(plug, from_schedule);
|
|
|
|
if (list_empty(&plug->list))
|
|
return;
|
|
|
|
list_splice_init(&plug->list, &list);
|
|
|
|
list_sort(NULL, &list, plug_rq_cmp);
|
|
|
|
q = NULL;
|
|
depth = 0;
|
|
|
|
/*
|
|
* Save and disable interrupts here, to avoid doing it for every
|
|
* queue lock we have to take.
|
|
*/
|
|
local_irq_save(flags);
|
|
while (!list_empty(&list)) {
|
|
rq = list_entry_rq(list.next);
|
|
list_del_init(&rq->queuelist);
|
|
BUG_ON(!rq->q);
|
|
if (rq->q != q) {
|
|
/*
|
|
* This drops the queue lock
|
|
*/
|
|
if (q)
|
|
queue_unplugged(q, depth, from_schedule);
|
|
q = rq->q;
|
|
depth = 0;
|
|
spin_lock(q->queue_lock);
|
|
}
|
|
|
|
/*
|
|
* Short-circuit if @q is dead
|
|
*/
|
|
if (unlikely(blk_queue_dying(q))) {
|
|
__blk_end_request_all(rq, -ENODEV);
|
|
continue;
|
|
}
|
|
|
|
/*
|
|
* rq is already accounted, so use raw insert
|
|
*/
|
|
if (op_is_flush(rq->cmd_flags))
|
|
__elv_add_request(q, rq, ELEVATOR_INSERT_FLUSH);
|
|
else
|
|
__elv_add_request(q, rq, ELEVATOR_INSERT_SORT_MERGE);
|
|
|
|
depth++;
|
|
}
|
|
|
|
/*
|
|
* This drops the queue lock
|
|
*/
|
|
if (q)
|
|
queue_unplugged(q, depth, from_schedule);
|
|
|
|
local_irq_restore(flags);
|
|
}
|
|
|
|
void blk_finish_plug(struct blk_plug *plug)
|
|
{
|
|
if (plug != current->plug)
|
|
return;
|
|
blk_flush_plug_list(plug, false);
|
|
|
|
current->plug = NULL;
|
|
}
|
|
EXPORT_SYMBOL(blk_finish_plug);
|
|
|
|
#ifdef CONFIG_PM
|
|
/**
|
|
* blk_pm_runtime_init - Block layer runtime PM initialization routine
|
|
* @q: the queue of the device
|
|
* @dev: the device the queue belongs to
|
|
*
|
|
* Description:
|
|
* Initialize runtime-PM-related fields for @q and start auto suspend for
|
|
* @dev. Drivers that want to take advantage of request-based runtime PM
|
|
* should call this function after @dev has been initialized, and its
|
|
* request queue @q has been allocated, and runtime PM for it can not happen
|
|
* yet(either due to disabled/forbidden or its usage_count > 0). In most
|
|
* cases, driver should call this function before any I/O has taken place.
|
|
*
|
|
* This function takes care of setting up using auto suspend for the device,
|
|
* the autosuspend delay is set to -1 to make runtime suspend impossible
|
|
* until an updated value is either set by user or by driver. Drivers do
|
|
* not need to touch other autosuspend settings.
|
|
*
|
|
* The block layer runtime PM is request based, so only works for drivers
|
|
* that use request as their IO unit instead of those directly use bio's.
|
|
*/
|
|
void blk_pm_runtime_init(struct request_queue *q, struct device *dev)
|
|
{
|
|
q->dev = dev;
|
|
q->rpm_status = RPM_ACTIVE;
|
|
pm_runtime_set_autosuspend_delay(q->dev, -1);
|
|
pm_runtime_use_autosuspend(q->dev);
|
|
}
|
|
EXPORT_SYMBOL(blk_pm_runtime_init);
|
|
|
|
/**
|
|
* blk_pre_runtime_suspend - Pre runtime suspend check
|
|
* @q: the queue of the device
|
|
*
|
|
* Description:
|
|
* This function will check if runtime suspend is allowed for the device
|
|
* by examining if there are any requests pending in the queue. If there
|
|
* are requests pending, the device can not be runtime suspended; otherwise,
|
|
* the queue's status will be updated to SUSPENDING and the driver can
|
|
* proceed to suspend the device.
|
|
*
|
|
* For the not allowed case, we mark last busy for the device so that
|
|
* runtime PM core will try to autosuspend it some time later.
|
|
*
|
|
* This function should be called near the start of the device's
|
|
* runtime_suspend callback.
|
|
*
|
|
* Return:
|
|
* 0 - OK to runtime suspend the device
|
|
* -EBUSY - Device should not be runtime suspended
|
|
*/
|
|
int blk_pre_runtime_suspend(struct request_queue *q)
|
|
{
|
|
int ret = 0;
|
|
|
|
if (!q->dev)
|
|
return ret;
|
|
|
|
spin_lock_irq(q->queue_lock);
|
|
if (q->nr_pending) {
|
|
ret = -EBUSY;
|
|
pm_runtime_mark_last_busy(q->dev);
|
|
} else {
|
|
q->rpm_status = RPM_SUSPENDING;
|
|
}
|
|
spin_unlock_irq(q->queue_lock);
|
|
return ret;
|
|
}
|
|
EXPORT_SYMBOL(blk_pre_runtime_suspend);
|
|
|
|
/**
|
|
* blk_post_runtime_suspend - Post runtime suspend processing
|
|
* @q: the queue of the device
|
|
* @err: return value of the device's runtime_suspend function
|
|
*
|
|
* Description:
|
|
* Update the queue's runtime status according to the return value of the
|
|
* device's runtime suspend function and mark last busy for the device so
|
|
* that PM core will try to auto suspend the device at a later time.
|
|
*
|
|
* This function should be called near the end of the device's
|
|
* runtime_suspend callback.
|
|
*/
|
|
void blk_post_runtime_suspend(struct request_queue *q, int err)
|
|
{
|
|
if (!q->dev)
|
|
return;
|
|
|
|
spin_lock_irq(q->queue_lock);
|
|
if (!err) {
|
|
q->rpm_status = RPM_SUSPENDED;
|
|
} else {
|
|
q->rpm_status = RPM_ACTIVE;
|
|
pm_runtime_mark_last_busy(q->dev);
|
|
}
|
|
spin_unlock_irq(q->queue_lock);
|
|
}
|
|
EXPORT_SYMBOL(blk_post_runtime_suspend);
|
|
|
|
/**
|
|
* blk_pre_runtime_resume - Pre runtime resume processing
|
|
* @q: the queue of the device
|
|
*
|
|
* Description:
|
|
* Update the queue's runtime status to RESUMING in preparation for the
|
|
* runtime resume of the device.
|
|
*
|
|
* This function should be called near the start of the device's
|
|
* runtime_resume callback.
|
|
*/
|
|
void blk_pre_runtime_resume(struct request_queue *q)
|
|
{
|
|
if (!q->dev)
|
|
return;
|
|
|
|
spin_lock_irq(q->queue_lock);
|
|
q->rpm_status = RPM_RESUMING;
|
|
spin_unlock_irq(q->queue_lock);
|
|
}
|
|
EXPORT_SYMBOL(blk_pre_runtime_resume);
|
|
|
|
/**
|
|
* blk_post_runtime_resume - Post runtime resume processing
|
|
* @q: the queue of the device
|
|
* @err: return value of the device's runtime_resume function
|
|
*
|
|
* Description:
|
|
* Update the queue's runtime status according to the return value of the
|
|
* device's runtime_resume function. If it is successfully resumed, process
|
|
* the requests that are queued into the device's queue when it is resuming
|
|
* and then mark last busy and initiate autosuspend for it.
|
|
*
|
|
* This function should be called near the end of the device's
|
|
* runtime_resume callback.
|
|
*/
|
|
void blk_post_runtime_resume(struct request_queue *q, int err)
|
|
{
|
|
if (!q->dev)
|
|
return;
|
|
|
|
spin_lock_irq(q->queue_lock);
|
|
if (!err) {
|
|
q->rpm_status = RPM_ACTIVE;
|
|
__blk_run_queue(q);
|
|
pm_runtime_mark_last_busy(q->dev);
|
|
pm_request_autosuspend(q->dev);
|
|
} else {
|
|
q->rpm_status = RPM_SUSPENDED;
|
|
}
|
|
spin_unlock_irq(q->queue_lock);
|
|
}
|
|
EXPORT_SYMBOL(blk_post_runtime_resume);
|
|
|
|
/**
|
|
* blk_set_runtime_active - Force runtime status of the queue to be active
|
|
* @q: the queue of the device
|
|
*
|
|
* If the device is left runtime suspended during system suspend the resume
|
|
* hook typically resumes the device and corrects runtime status
|
|
* accordingly. However, that does not affect the queue runtime PM status
|
|
* which is still "suspended". This prevents processing requests from the
|
|
* queue.
|
|
*
|
|
* This function can be used in driver's resume hook to correct queue
|
|
* runtime PM status and re-enable peeking requests from the queue. It
|
|
* should be called before first request is added to the queue.
|
|
*/
|
|
void blk_set_runtime_active(struct request_queue *q)
|
|
{
|
|
spin_lock_irq(q->queue_lock);
|
|
q->rpm_status = RPM_ACTIVE;
|
|
pm_runtime_mark_last_busy(q->dev);
|
|
pm_request_autosuspend(q->dev);
|
|
spin_unlock_irq(q->queue_lock);
|
|
}
|
|
EXPORT_SYMBOL(blk_set_runtime_active);
|
|
#endif
|
|
|
|
int __init blk_dev_init(void)
|
|
{
|
|
BUILD_BUG_ON(REQ_OP_LAST >= (1 << REQ_OP_BITS));
|
|
BUILD_BUG_ON(REQ_OP_BITS + REQ_FLAG_BITS > 8 *
|
|
FIELD_SIZEOF(struct request, cmd_flags));
|
|
BUILD_BUG_ON(REQ_OP_BITS + REQ_FLAG_BITS > 8 *
|
|
FIELD_SIZEOF(struct bio, bi_opf));
|
|
|
|
/* used for unplugging and affects IO latency/throughput - HIGHPRI */
|
|
kblockd_workqueue = alloc_workqueue("kblockd",
|
|
WQ_MEM_RECLAIM | WQ_HIGHPRI, 0);
|
|
if (!kblockd_workqueue)
|
|
panic("Failed to create kblockd\n");
|
|
|
|
request_cachep = kmem_cache_create("blkdev_requests",
|
|
sizeof(struct request), 0, SLAB_PANIC, NULL);
|
|
|
|
blk_requestq_cachep = kmem_cache_create("request_queue",
|
|
sizeof(struct request_queue), 0, SLAB_PANIC, NULL);
|
|
|
|
return 0;
|
|
}
|