1796 lines
48 KiB
C
1796 lines
48 KiB
C
/*
|
|
* Copyright (C) 1991, 1992 Linus Torvalds
|
|
* Copyright (C) 1994, Karl Keyte: Added support for disk statistics
|
|
* Elevator latency, (C) 2000 Andrea Arcangeli <andrea@suse.de> SuSE
|
|
* Queue request tables / lock, selectable elevator, Jens Axboe <axboe@suse.de>
|
|
* kernel-doc documentation started by NeilBrown <neilb@cse.unsw.edu.au>
|
|
* - July2000
|
|
* bio rewrite, highmem i/o, etc, Jens Axboe <axboe@suse.de> - may 2001
|
|
*/
|
|
|
|
/*
|
|
* This handles all read/write requests to block devices
|
|
*/
|
|
#include <linux/kernel.h>
|
|
#include <linux/module.h>
|
|
#include <linux/backing-dev.h>
|
|
#include <linux/bio.h>
|
|
#include <linux/blkdev.h>
|
|
#include <linux/blk-mq.h>
|
|
#include <linux/highmem.h>
|
|
#include <linux/mm.h>
|
|
#include <linux/kernel_stat.h>
|
|
#include <linux/string.h>
|
|
#include <linux/init.h>
|
|
#include <linux/completion.h>
|
|
#include <linux/slab.h>
|
|
#include <linux/swap.h>
|
|
#include <linux/writeback.h>
|
|
#include <linux/task_io_accounting_ops.h>
|
|
#include <linux/fault-inject.h>
|
|
#include <linux/list_sort.h>
|
|
#include <linux/delay.h>
|
|
#include <linux/ratelimit.h>
|
|
#include <linux/pm_runtime.h>
|
|
#include <linux/blk-cgroup.h>
|
|
#include <linux/debugfs.h>
|
|
#include <linux/bpf.h>
|
|
|
|
#define CREATE_TRACE_POINTS
|
|
#include <trace/events/block.h>
|
|
|
|
#include "blk.h"
|
|
#include "blk-mq.h"
|
|
#include "blk-mq-sched.h"
|
|
#include "blk-pm.h"
|
|
#include "blk-rq-qos.h"
|
|
|
|
#ifdef CONFIG_DEBUG_FS
|
|
struct dentry *blk_debugfs_root;
|
|
#endif
|
|
|
|
EXPORT_TRACEPOINT_SYMBOL_GPL(block_bio_remap);
|
|
EXPORT_TRACEPOINT_SYMBOL_GPL(block_rq_remap);
|
|
EXPORT_TRACEPOINT_SYMBOL_GPL(block_bio_complete);
|
|
EXPORT_TRACEPOINT_SYMBOL_GPL(block_split);
|
|
EXPORT_TRACEPOINT_SYMBOL_GPL(block_unplug);
|
|
|
|
DEFINE_IDA(blk_queue_ida);
|
|
|
|
/*
|
|
* For queue allocation
|
|
*/
|
|
struct kmem_cache *blk_requestq_cachep;
|
|
|
|
/*
|
|
* Controlling structure to kblockd
|
|
*/
|
|
static struct workqueue_struct *kblockd_workqueue;
|
|
|
|
/**
|
|
* blk_queue_flag_set - atomically set a queue flag
|
|
* @flag: flag to be set
|
|
* @q: request queue
|
|
*/
|
|
void blk_queue_flag_set(unsigned int flag, struct request_queue *q)
|
|
{
|
|
set_bit(flag, &q->queue_flags);
|
|
}
|
|
EXPORT_SYMBOL(blk_queue_flag_set);
|
|
|
|
/**
|
|
* blk_queue_flag_clear - atomically clear a queue flag
|
|
* @flag: flag to be cleared
|
|
* @q: request queue
|
|
*/
|
|
void blk_queue_flag_clear(unsigned int flag, struct request_queue *q)
|
|
{
|
|
clear_bit(flag, &q->queue_flags);
|
|
}
|
|
EXPORT_SYMBOL(blk_queue_flag_clear);
|
|
|
|
/**
|
|
* blk_queue_flag_test_and_set - atomically test and set a queue flag
|
|
* @flag: flag to be set
|
|
* @q: request queue
|
|
*
|
|
* Returns the previous value of @flag - 0 if the flag was not set and 1 if
|
|
* the flag was already set.
|
|
*/
|
|
bool blk_queue_flag_test_and_set(unsigned int flag, struct request_queue *q)
|
|
{
|
|
return test_and_set_bit(flag, &q->queue_flags);
|
|
}
|
|
EXPORT_SYMBOL_GPL(blk_queue_flag_test_and_set);
|
|
|
|
void blk_rq_init(struct request_queue *q, struct request *rq)
|
|
{
|
|
memset(rq, 0, sizeof(*rq));
|
|
|
|
INIT_LIST_HEAD(&rq->queuelist);
|
|
rq->q = q;
|
|
rq->__sector = (sector_t) -1;
|
|
INIT_HLIST_NODE(&rq->hash);
|
|
RB_CLEAR_NODE(&rq->rb_node);
|
|
rq->tag = -1;
|
|
rq->internal_tag = -1;
|
|
rq->start_time_ns = ktime_get_ns();
|
|
rq->part = NULL;
|
|
}
|
|
EXPORT_SYMBOL(blk_rq_init);
|
|
|
|
static const struct {
|
|
int errno;
|
|
const char *name;
|
|
} blk_errors[] = {
|
|
[BLK_STS_OK] = { 0, "" },
|
|
[BLK_STS_NOTSUPP] = { -EOPNOTSUPP, "operation not supported" },
|
|
[BLK_STS_TIMEOUT] = { -ETIMEDOUT, "timeout" },
|
|
[BLK_STS_NOSPC] = { -ENOSPC, "critical space allocation" },
|
|
[BLK_STS_TRANSPORT] = { -ENOLINK, "recoverable transport" },
|
|
[BLK_STS_TARGET] = { -EREMOTEIO, "critical target" },
|
|
[BLK_STS_NEXUS] = { -EBADE, "critical nexus" },
|
|
[BLK_STS_MEDIUM] = { -ENODATA, "critical medium" },
|
|
[BLK_STS_PROTECTION] = { -EILSEQ, "protection" },
|
|
[BLK_STS_RESOURCE] = { -ENOMEM, "kernel resource" },
|
|
[BLK_STS_DEV_RESOURCE] = { -EBUSY, "device resource" },
|
|
[BLK_STS_AGAIN] = { -EAGAIN, "nonblocking retry" },
|
|
|
|
/* device mapper special case, should not leak out: */
|
|
[BLK_STS_DM_REQUEUE] = { -EREMCHG, "dm internal retry" },
|
|
|
|
/* everything else not covered above: */
|
|
[BLK_STS_IOERR] = { -EIO, "I/O" },
|
|
};
|
|
|
|
blk_status_t errno_to_blk_status(int errno)
|
|
{
|
|
int i;
|
|
|
|
for (i = 0; i < ARRAY_SIZE(blk_errors); i++) {
|
|
if (blk_errors[i].errno == errno)
|
|
return (__force blk_status_t)i;
|
|
}
|
|
|
|
return BLK_STS_IOERR;
|
|
}
|
|
EXPORT_SYMBOL_GPL(errno_to_blk_status);
|
|
|
|
int blk_status_to_errno(blk_status_t status)
|
|
{
|
|
int idx = (__force int)status;
|
|
|
|
if (WARN_ON_ONCE(idx >= ARRAY_SIZE(blk_errors)))
|
|
return -EIO;
|
|
return blk_errors[idx].errno;
|
|
}
|
|
EXPORT_SYMBOL_GPL(blk_status_to_errno);
|
|
|
|
static void print_req_error(struct request *req, blk_status_t status)
|
|
{
|
|
int idx = (__force int)status;
|
|
|
|
if (WARN_ON_ONCE(idx >= ARRAY_SIZE(blk_errors)))
|
|
return;
|
|
|
|
printk_ratelimited(KERN_ERR "%s: %s error, dev %s, sector %llu flags %x\n",
|
|
__func__, blk_errors[idx].name,
|
|
req->rq_disk ? req->rq_disk->disk_name : "?",
|
|
(unsigned long long)blk_rq_pos(req),
|
|
req->cmd_flags);
|
|
}
|
|
|
|
static void req_bio_endio(struct request *rq, struct bio *bio,
|
|
unsigned int nbytes, blk_status_t error)
|
|
{
|
|
if (error)
|
|
bio->bi_status = error;
|
|
|
|
if (unlikely(rq->rq_flags & RQF_QUIET))
|
|
bio_set_flag(bio, BIO_QUIET);
|
|
|
|
bio_advance(bio, nbytes);
|
|
|
|
/* don't actually finish bio if it's part of flush sequence */
|
|
if (bio->bi_iter.bi_size == 0 && !(rq->rq_flags & RQF_FLUSH_SEQ))
|
|
bio_endio(bio);
|
|
}
|
|
|
|
void blk_dump_rq_flags(struct request *rq, char *msg)
|
|
{
|
|
printk(KERN_INFO "%s: dev %s: flags=%llx\n", msg,
|
|
rq->rq_disk ? rq->rq_disk->disk_name : "?",
|
|
(unsigned long long) rq->cmd_flags);
|
|
|
|
printk(KERN_INFO " sector %llu, nr/cnr %u/%u\n",
|
|
(unsigned long long)blk_rq_pos(rq),
|
|
blk_rq_sectors(rq), blk_rq_cur_sectors(rq));
|
|
printk(KERN_INFO " bio %p, biotail %p, len %u\n",
|
|
rq->bio, rq->biotail, blk_rq_bytes(rq));
|
|
}
|
|
EXPORT_SYMBOL(blk_dump_rq_flags);
|
|
|
|
/**
|
|
* blk_sync_queue - cancel any pending callbacks on a queue
|
|
* @q: the queue
|
|
*
|
|
* Description:
|
|
* The block layer may perform asynchronous callback activity
|
|
* on a queue, such as calling the unplug function after a timeout.
|
|
* A block device may call blk_sync_queue to ensure that any
|
|
* such activity is cancelled, thus allowing it to release resources
|
|
* that the callbacks might use. The caller must already have made sure
|
|
* that its ->make_request_fn will not re-add plugging prior to calling
|
|
* this function.
|
|
*
|
|
* This function does not cancel any asynchronous activity arising
|
|
* out of elevator or throttling code. That would require elevator_exit()
|
|
* and blkcg_exit_queue() to be called with queue lock initialized.
|
|
*
|
|
*/
|
|
void blk_sync_queue(struct request_queue *q)
|
|
{
|
|
del_timer_sync(&q->timeout);
|
|
cancel_work_sync(&q->timeout_work);
|
|
|
|
if (queue_is_mq(q)) {
|
|
struct blk_mq_hw_ctx *hctx;
|
|
int i;
|
|
|
|
cancel_delayed_work_sync(&q->requeue_work);
|
|
queue_for_each_hw_ctx(q, hctx, i)
|
|
cancel_delayed_work_sync(&hctx->run_work);
|
|
}
|
|
}
|
|
EXPORT_SYMBOL(blk_sync_queue);
|
|
|
|
/**
|
|
* blk_set_pm_only - increment pm_only counter
|
|
* @q: request queue pointer
|
|
*/
|
|
void blk_set_pm_only(struct request_queue *q)
|
|
{
|
|
atomic_inc(&q->pm_only);
|
|
}
|
|
EXPORT_SYMBOL_GPL(blk_set_pm_only);
|
|
|
|
void blk_clear_pm_only(struct request_queue *q)
|
|
{
|
|
int pm_only;
|
|
|
|
pm_only = atomic_dec_return(&q->pm_only);
|
|
WARN_ON_ONCE(pm_only < 0);
|
|
if (pm_only == 0)
|
|
wake_up_all(&q->mq_freeze_wq);
|
|
}
|
|
EXPORT_SYMBOL_GPL(blk_clear_pm_only);
|
|
|
|
void blk_put_queue(struct request_queue *q)
|
|
{
|
|
kobject_put(&q->kobj);
|
|
}
|
|
EXPORT_SYMBOL(blk_put_queue);
|
|
|
|
void blk_set_queue_dying(struct request_queue *q)
|
|
{
|
|
blk_queue_flag_set(QUEUE_FLAG_DYING, q);
|
|
|
|
/*
|
|
* When queue DYING flag is set, we need to block new req
|
|
* entering queue, so we call blk_freeze_queue_start() to
|
|
* prevent I/O from crossing blk_queue_enter().
|
|
*/
|
|
blk_freeze_queue_start(q);
|
|
|
|
if (queue_is_mq(q))
|
|
blk_mq_wake_waiters(q);
|
|
|
|
/* Make blk_queue_enter() reexamine the DYING flag. */
|
|
wake_up_all(&q->mq_freeze_wq);
|
|
}
|
|
EXPORT_SYMBOL_GPL(blk_set_queue_dying);
|
|
|
|
/* Unconfigure the I/O scheduler and dissociate from the cgroup controller. */
|
|
void blk_exit_queue(struct request_queue *q)
|
|
{
|
|
/*
|
|
* Since the I/O scheduler exit code may access cgroup information,
|
|
* perform I/O scheduler exit before disassociating from the block
|
|
* cgroup controller.
|
|
*/
|
|
if (q->elevator) {
|
|
ioc_clear_queue(q);
|
|
elevator_exit(q, q->elevator);
|
|
q->elevator = NULL;
|
|
}
|
|
|
|
/*
|
|
* Remove all references to @q from the block cgroup controller before
|
|
* restoring @q->queue_lock to avoid that restoring this pointer causes
|
|
* e.g. blkcg_print_blkgs() to crash.
|
|
*/
|
|
blkcg_exit_queue(q);
|
|
|
|
/*
|
|
* Since the cgroup code may dereference the @q->backing_dev_info
|
|
* pointer, only decrease its reference count after having removed the
|
|
* association with the block cgroup controller.
|
|
*/
|
|
bdi_put(q->backing_dev_info);
|
|
}
|
|
|
|
/**
|
|
* 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)
|
|
{
|
|
/* mark @q DYING, no new request or merges will be allowed afterwards */
|
|
mutex_lock(&q->sysfs_lock);
|
|
blk_set_queue_dying(q);
|
|
|
|
blk_queue_flag_set(QUEUE_FLAG_NOMERGES, q);
|
|
blk_queue_flag_set(QUEUE_FLAG_NOXMERGES, q);
|
|
blk_queue_flag_set(QUEUE_FLAG_DYING, q);
|
|
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);
|
|
|
|
rq_qos_exit(q);
|
|
|
|
blk_queue_flag_set(QUEUE_FLAG_DEAD, q);
|
|
|
|
/*
|
|
* make sure all in-progress dispatch are completed because
|
|
* blk_freeze_queue() can only complete all requests, and
|
|
* dispatch may still be in-progress since we dispatch requests
|
|
* from more than one contexts.
|
|
*
|
|
* We rely on driver to deal with the race in case that queue
|
|
* initialization isn't done.
|
|
*/
|
|
if (queue_is_mq(q) && blk_queue_init_done(q))
|
|
blk_mq_quiesce_queue(q);
|
|
|
|
/* 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);
|
|
|
|
/*
|
|
* I/O scheduler exit is only safe after the sysfs scheduler attribute
|
|
* has been removed.
|
|
*/
|
|
WARN_ON_ONCE(q->kobj.state_in_sysfs);
|
|
|
|
blk_exit_queue(q);
|
|
|
|
if (queue_is_mq(q))
|
|
blk_mq_free_queue(q);
|
|
|
|
percpu_ref_exit(&q->q_usage_counter);
|
|
|
|
/* @q is and will stay empty, shutdown and put */
|
|
blk_put_queue(q);
|
|
}
|
|
EXPORT_SYMBOL(blk_cleanup_queue);
|
|
|
|
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);
|
|
|
|
/**
|
|
* blk_queue_enter() - try to increase q->q_usage_counter
|
|
* @q: request queue pointer
|
|
* @flags: BLK_MQ_REQ_NOWAIT and/or BLK_MQ_REQ_PREEMPT
|
|
*/
|
|
int blk_queue_enter(struct request_queue *q, blk_mq_req_flags_t flags)
|
|
{
|
|
const bool pm = flags & BLK_MQ_REQ_PREEMPT;
|
|
|
|
while (true) {
|
|
bool success = false;
|
|
|
|
rcu_read_lock();
|
|
if (percpu_ref_tryget_live(&q->q_usage_counter)) {
|
|
/*
|
|
* The code that increments the pm_only counter is
|
|
* responsible for ensuring that that counter is
|
|
* globally visible before the queue is unfrozen.
|
|
*/
|
|
if (pm || !blk_queue_pm_only(q)) {
|
|
success = true;
|
|
} else {
|
|
percpu_ref_put(&q->q_usage_counter);
|
|
}
|
|
}
|
|
rcu_read_unlock();
|
|
|
|
if (success)
|
|
return 0;
|
|
|
|
if (flags & BLK_MQ_REQ_NOWAIT)
|
|
return -EBUSY;
|
|
|
|
/*
|
|
* read pair of barrier in blk_freeze_queue_start(),
|
|
* we need to order reading __PERCPU_REF_DEAD flag of
|
|
* .q_usage_counter and reading .mq_freeze_depth or
|
|
* queue dying flag, otherwise the following wait may
|
|
* never return if the two reads are reordered.
|
|
*/
|
|
smp_rmb();
|
|
|
|
wait_event(q->mq_freeze_wq,
|
|
(atomic_read(&q->mq_freeze_depth) == 0 &&
|
|
(pm || (blk_pm_request_resume(q),
|
|
!blk_queue_pm_only(q)))) ||
|
|
blk_queue_dying(q));
|
|
if (blk_queue_dying(q))
|
|
return -ENODEV;
|
|
}
|
|
}
|
|
|
|
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(struct timer_list *t)
|
|
{
|
|
struct request_queue *q = from_timer(q, t, timeout);
|
|
|
|
kblockd_schedule_work(&q->timeout_work);
|
|
}
|
|
|
|
/**
|
|
* blk_alloc_queue_node - allocate a request queue
|
|
* @gfp_mask: memory allocation flags
|
|
* @node_id: NUMA node to allocate memory from
|
|
*/
|
|
struct request_queue *blk_alloc_queue_node(gfp_t gfp_mask, int node_id)
|
|
{
|
|
struct request_queue *q;
|
|
int ret;
|
|
|
|
q = kmem_cache_alloc_node(blk_requestq_cachep,
|
|
gfp_mask | __GFP_ZERO, node_id);
|
|
if (!q)
|
|
return NULL;
|
|
|
|
INIT_LIST_HEAD(&q->queue_head);
|
|
q->last_merge = NULL;
|
|
|
|
q->id = ida_simple_get(&blk_queue_ida, 0, 0, gfp_mask);
|
|
if (q->id < 0)
|
|
goto fail_q;
|
|
|
|
ret = bioset_init(&q->bio_split, BIO_POOL_SIZE, 0, BIOSET_NEED_BVECS);
|
|
if (ret)
|
|
goto fail_id;
|
|
|
|
q->backing_dev_info = bdi_alloc_node(gfp_mask, node_id);
|
|
if (!q->backing_dev_info)
|
|
goto fail_split;
|
|
|
|
q->stats = blk_alloc_queue_stats();
|
|
if (!q->stats)
|
|
goto fail_stats;
|
|
|
|
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;
|
|
|
|
timer_setup(&q->backing_dev_info->laptop_mode_wb_timer,
|
|
laptop_mode_timer_fn, 0);
|
|
timer_setup(&q->timeout, blk_rq_timed_out_timer, 0);
|
|
INIT_WORK(&q->timeout_work, NULL);
|
|
INIT_LIST_HEAD(&q->icq_list);
|
|
#ifdef CONFIG_BLK_CGROUP
|
|
INIT_LIST_HEAD(&q->blkg_list);
|
|
#endif
|
|
|
|
kobject_init(&q->kobj, &blk_queue_ktype);
|
|
|
|
#ifdef CONFIG_BLK_DEV_IO_TRACE
|
|
mutex_init(&q->blk_trace_mutex);
|
|
#endif
|
|
mutex_init(&q->sysfs_lock);
|
|
spin_lock_init(&q->queue_lock);
|
|
|
|
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:
|
|
blk_free_queue_stats(q->stats);
|
|
fail_stats:
|
|
bdi_put(q->backing_dev_info);
|
|
fail_split:
|
|
bioset_exit(&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);
|
|
|
|
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);
|
|
|
|
/**
|
|
* blk_get_request - allocate a request
|
|
* @q: request queue to allocate a request for
|
|
* @op: operation (REQ_OP_*) and REQ_* flags, e.g. REQ_SYNC.
|
|
* @flags: BLK_MQ_REQ_* flags, e.g. BLK_MQ_REQ_NOWAIT.
|
|
*/
|
|
struct request *blk_get_request(struct request_queue *q, unsigned int op,
|
|
blk_mq_req_flags_t flags)
|
|
{
|
|
struct request *req;
|
|
|
|
WARN_ON_ONCE(op & REQ_NOWAIT);
|
|
WARN_ON_ONCE(flags & ~(BLK_MQ_REQ_NOWAIT | BLK_MQ_REQ_PREEMPT));
|
|
|
|
req = blk_mq_alloc_request(q, op, flags);
|
|
if (!IS_ERR(req) && q->mq_ops->initialize_rq_fn)
|
|
q->mq_ops->initialize_rq_fn(req);
|
|
|
|
return req;
|
|
}
|
|
EXPORT_SYMBOL(blk_get_request);
|
|
|
|
void blk_put_request(struct request *req)
|
|
{
|
|
blk_mq_free_request(req);
|
|
}
|
|
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;
|
|
|
|
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;
|
|
|
|
blk_account_io_start(req, false);
|
|
return true;
|
|
}
|
|
|
|
bool bio_attempt_discard_merge(struct request_queue *q, struct request *req,
|
|
struct bio *bio)
|
|
{
|
|
unsigned short segments = blk_rq_nr_discard_segments(req);
|
|
|
|
if (segments >= queue_max_discard_segments(q))
|
|
goto no_merge;
|
|
if (blk_rq_sectors(req) + bio_sectors(bio) >
|
|
blk_rq_get_max_sectors(req, blk_rq_pos(req)))
|
|
goto no_merge;
|
|
|
|
req->biotail->bi_next = bio;
|
|
req->biotail = bio;
|
|
req->__data_len += bio->bi_iter.bi_size;
|
|
req->nr_phys_segments = segments + 1;
|
|
|
|
blk_account_io_start(req, false);
|
|
return true;
|
|
no_merge:
|
|
req_set_nomerge(q, req);
|
|
return false;
|
|
}
|
|
|
|
/**
|
|
* 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,
|
|
struct request **same_queue_rq)
|
|
{
|
|
struct blk_plug *plug;
|
|
struct request *rq;
|
|
struct list_head *plug_list;
|
|
|
|
plug = current->plug;
|
|
if (!plug)
|
|
return false;
|
|
|
|
plug_list = &plug->mq_list;
|
|
|
|
list_for_each_entry_reverse(rq, plug_list, queuelist) {
|
|
bool merged = false;
|
|
|
|
if (rq->q == q && same_queue_rq) {
|
|
/*
|
|
* Only blk-mq multiple hardware queues case checks the
|
|
* rq in the same queue, there should be only one such
|
|
* rq in a queue
|
|
**/
|
|
*same_queue_rq = rq;
|
|
}
|
|
|
|
if (rq->q != q || !blk_rq_merge_ok(rq, bio))
|
|
continue;
|
|
|
|
switch (blk_try_merge(rq, bio)) {
|
|
case ELEVATOR_BACK_MERGE:
|
|
merged = bio_attempt_back_merge(q, rq, bio);
|
|
break;
|
|
case ELEVATOR_FRONT_MERGE:
|
|
merged = bio_attempt_front_merge(q, rq, bio);
|
|
break;
|
|
case ELEVATOR_DISCARD_MERGE:
|
|
merged = bio_attempt_discard_merge(q, rq, bio);
|
|
break;
|
|
default:
|
|
break;
|
|
}
|
|
|
|
if (merged)
|
|
return true;
|
|
}
|
|
|
|
return false;
|
|
}
|
|
|
|
void blk_init_request_from_bio(struct request *req, struct bio *bio)
|
|
{
|
|
if (bio->bi_opf & REQ_RAHEAD)
|
|
req->cmd_flags |= REQ_FAILFAST_MASK;
|
|
|
|
req->__sector = bio->bi_iter.bi_sector;
|
|
req->ioprio = bio_prio(bio);
|
|
req->write_hint = bio->bi_write_hint;
|
|
blk_rq_bio_prep(req->q, req, bio);
|
|
}
|
|
EXPORT_SYMBOL_GPL(blk_init_request_from_bio);
|
|
|
|
static void handle_bad_sector(struct bio *bio, sector_t maxsector)
|
|
{
|
|
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",
|
|
bio_devname(bio, b), bio->bi_opf,
|
|
(unsigned long long)bio_end_sector(bio),
|
|
(long long)maxsector);
|
|
}
|
|
|
|
#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 */
|
|
|
|
static inline bool bio_check_ro(struct bio *bio, struct hd_struct *part)
|
|
{
|
|
const int op = bio_op(bio);
|
|
|
|
if (part->policy && op_is_write(op)) {
|
|
char b[BDEVNAME_SIZE];
|
|
|
|
if (op_is_flush(bio->bi_opf) && !bio_sectors(bio))
|
|
return false;
|
|
|
|
WARN_ONCE(1,
|
|
"generic_make_request: Trying to write "
|
|
"to read-only block-device %s (partno %d)\n",
|
|
bio_devname(bio, b), part->partno);
|
|
/* Older lvm-tools actually trigger this */
|
|
return false;
|
|
}
|
|
|
|
return false;
|
|
}
|
|
|
|
static noinline int should_fail_bio(struct bio *bio)
|
|
{
|
|
if (should_fail_request(&bio->bi_disk->part0, bio->bi_iter.bi_size))
|
|
return -EIO;
|
|
return 0;
|
|
}
|
|
ALLOW_ERROR_INJECTION(should_fail_bio, ERRNO);
|
|
|
|
/*
|
|
* Check whether this bio extends beyond the end of the device or partition.
|
|
* This may well happen - the kernel calls bread() without checking the size of
|
|
* the device, e.g., when mounting a file system.
|
|
*/
|
|
static inline int bio_check_eod(struct bio *bio, sector_t maxsector)
|
|
{
|
|
unsigned int nr_sectors = bio_sectors(bio);
|
|
|
|
if (nr_sectors && maxsector &&
|
|
(nr_sectors > maxsector ||
|
|
bio->bi_iter.bi_sector > maxsector - nr_sectors)) {
|
|
handle_bad_sector(bio, maxsector);
|
|
return -EIO;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* Remap block n of partition p to block n+start(p) of the disk.
|
|
*/
|
|
static inline int blk_partition_remap(struct bio *bio)
|
|
{
|
|
struct hd_struct *p;
|
|
int ret = -EIO;
|
|
|
|
rcu_read_lock();
|
|
p = __disk_get_part(bio->bi_disk, bio->bi_partno);
|
|
if (unlikely(!p))
|
|
goto out;
|
|
if (unlikely(should_fail_request(p, bio->bi_iter.bi_size)))
|
|
goto out;
|
|
if (unlikely(bio_check_ro(bio, p)))
|
|
goto out;
|
|
|
|
/*
|
|
* 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 (bio_sectors(bio) || bio_op(bio) == REQ_OP_ZONE_RESET) {
|
|
if (bio_check_eod(bio, part_nr_sects_read(p)))
|
|
goto out;
|
|
bio->bi_iter.bi_sector += p->start_sect;
|
|
trace_block_bio_remap(bio->bi_disk->queue, bio, part_devt(p),
|
|
bio->bi_iter.bi_sector - p->start_sect);
|
|
}
|
|
bio->bi_partno = 0;
|
|
ret = 0;
|
|
out:
|
|
rcu_read_unlock();
|
|
return ret;
|
|
}
|
|
|
|
static noinline_for_stack bool
|
|
generic_make_request_checks(struct bio *bio)
|
|
{
|
|
struct request_queue *q;
|
|
int nr_sectors = bio_sectors(bio);
|
|
blk_status_t status = BLK_STS_IOERR;
|
|
char b[BDEVNAME_SIZE];
|
|
|
|
might_sleep();
|
|
|
|
q = bio->bi_disk->queue;
|
|
if (unlikely(!q)) {
|
|
printk(KERN_ERR
|
|
"generic_make_request: Trying to access "
|
|
"nonexistent block-device %s (%Lu)\n",
|
|
bio_devname(bio, b), (long long)bio->bi_iter.bi_sector);
|
|
goto end_io;
|
|
}
|
|
|
|
/*
|
|
* For a REQ_NOWAIT based request, return -EOPNOTSUPP
|
|
* if queue is not a request based queue.
|
|
*/
|
|
if ((bio->bi_opf & REQ_NOWAIT) && !queue_is_mq(q))
|
|
goto not_supported;
|
|
|
|
if (should_fail_bio(bio))
|
|
goto end_io;
|
|
|
|
if (bio->bi_partno) {
|
|
if (unlikely(blk_partition_remap(bio)))
|
|
goto end_io;
|
|
} else {
|
|
if (unlikely(bio_check_ro(bio, &bio->bi_disk->part0)))
|
|
goto end_io;
|
|
if (unlikely(bio_check_eod(bio, get_capacity(bio->bi_disk))))
|
|
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) {
|
|
status = BLK_STS_OK;
|
|
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 (!q->limits.max_write_same_sectors)
|
|
goto not_supported;
|
|
break;
|
|
case REQ_OP_ZONE_RESET:
|
|
if (!blk_queue_is_zoned(q))
|
|
goto not_supported;
|
|
break;
|
|
case REQ_OP_WRITE_ZEROES:
|
|
if (!q->limits.max_write_zeroes_sectors)
|
|
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;
|
|
|
|
if (!bio_flagged(bio, BIO_TRACE_COMPLETION)) {
|
|
trace_block_bio_queue(q, bio);
|
|
/* Now that enqueuing has been traced, we need to trace
|
|
* completion as well.
|
|
*/
|
|
bio_set_flag(bio, BIO_TRACE_COMPLETION);
|
|
}
|
|
return true;
|
|
|
|
not_supported:
|
|
status = BLK_STS_NOTSUPP;
|
|
end_io:
|
|
bio->bi_status = status;
|
|
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)
|
|
{
|
|
/*
|
|
* bio_list_on_stack[0] contains bios submitted by the current
|
|
* make_request_fn.
|
|
* bio_list_on_stack[1] contains bios that were submitted before
|
|
* the current make_request_fn, but that haven't been processed
|
|
* yet.
|
|
*/
|
|
struct bio_list bio_list_on_stack[2];
|
|
blk_mq_req_flags_t flags = 0;
|
|
struct request_queue *q = bio->bi_disk->queue;
|
|
blk_qc_t ret = BLK_QC_T_NONE;
|
|
|
|
if (bio->bi_opf & REQ_NOWAIT)
|
|
flags = BLK_MQ_REQ_NOWAIT;
|
|
if (bio_flagged(bio, BIO_QUEUE_ENTERED))
|
|
blk_queue_enter_live(q);
|
|
else if (blk_queue_enter(q, flags) < 0) {
|
|
if (!blk_queue_dying(q) && (bio->bi_opf & REQ_NOWAIT))
|
|
bio_wouldblock_error(bio);
|
|
else
|
|
bio_io_error(bio);
|
|
return ret;
|
|
}
|
|
|
|
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(¤t->bio_list[0], 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[0]);
|
|
current->bio_list = bio_list_on_stack;
|
|
do {
|
|
bool enter_succeeded = true;
|
|
|
|
if (unlikely(q != bio->bi_disk->queue)) {
|
|
if (q)
|
|
blk_queue_exit(q);
|
|
q = bio->bi_disk->queue;
|
|
flags = 0;
|
|
if (bio->bi_opf & REQ_NOWAIT)
|
|
flags = BLK_MQ_REQ_NOWAIT;
|
|
if (blk_queue_enter(q, flags) < 0) {
|
|
enter_succeeded = false;
|
|
q = NULL;
|
|
}
|
|
}
|
|
|
|
if (enter_succeeded) {
|
|
struct bio_list lower, same;
|
|
|
|
/* Create a fresh bio_list for all subordinate requests */
|
|
bio_list_on_stack[1] = bio_list_on_stack[0];
|
|
bio_list_init(&bio_list_on_stack[0]);
|
|
ret = q->make_request_fn(q, bio);
|
|
|
|
/* sort new bios into those for a lower level
|
|
* and those for the same level
|
|
*/
|
|
bio_list_init(&lower);
|
|
bio_list_init(&same);
|
|
while ((bio = bio_list_pop(&bio_list_on_stack[0])) != NULL)
|
|
if (q == bio->bi_disk->queue)
|
|
bio_list_add(&same, bio);
|
|
else
|
|
bio_list_add(&lower, bio);
|
|
/* now assemble so we handle the lowest level first */
|
|
bio_list_merge(&bio_list_on_stack[0], &lower);
|
|
bio_list_merge(&bio_list_on_stack[0], &same);
|
|
bio_list_merge(&bio_list_on_stack[0], &bio_list_on_stack[1]);
|
|
} else {
|
|
if (unlikely(!blk_queue_dying(q) &&
|
|
(bio->bi_opf & REQ_NOWAIT)))
|
|
bio_wouldblock_error(bio);
|
|
else
|
|
bio_io_error(bio);
|
|
}
|
|
bio = bio_list_pop(&bio_list_on_stack[0]);
|
|
} while (bio);
|
|
current->bio_list = NULL; /* deactivate */
|
|
|
|
out:
|
|
if (q)
|
|
blk_queue_exit(q);
|
|
return ret;
|
|
}
|
|
EXPORT_SYMBOL(generic_make_request);
|
|
|
|
/**
|
|
* direct_make_request - hand a buffer directly to its device driver for I/O
|
|
* @bio: The bio describing the location in memory and on the device.
|
|
*
|
|
* This function behaves like generic_make_request(), but does not protect
|
|
* against recursion. Must only be used if the called driver is known
|
|
* to not call generic_make_request (or direct_make_request) again from
|
|
* its make_request function. (Calling direct_make_request again from
|
|
* a workqueue is perfectly fine as that doesn't recurse).
|
|
*/
|
|
blk_qc_t direct_make_request(struct bio *bio)
|
|
{
|
|
struct request_queue *q = bio->bi_disk->queue;
|
|
bool nowait = bio->bi_opf & REQ_NOWAIT;
|
|
blk_qc_t ret;
|
|
|
|
if (!generic_make_request_checks(bio))
|
|
return BLK_QC_T_NONE;
|
|
|
|
if (unlikely(blk_queue_enter(q, nowait ? BLK_MQ_REQ_NOWAIT : 0))) {
|
|
if (nowait && !blk_queue_dying(q))
|
|
bio->bi_status = BLK_STS_AGAIN;
|
|
else
|
|
bio->bi_status = BLK_STS_IOERR;
|
|
bio_endio(bio);
|
|
return BLK_QC_T_NONE;
|
|
}
|
|
|
|
ret = q->make_request_fn(q, bio);
|
|
blk_queue_exit(q);
|
|
return ret;
|
|
}
|
|
EXPORT_SYMBOL_GPL(direct_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 = queue_logical_block_size(bio->bi_disk->queue) >> 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,
|
|
bio_devname(bio, 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
|
|
*/
|
|
blk_status_t blk_insert_cloned_request(struct request_queue *q, struct request *rq)
|
|
{
|
|
if (blk_cloned_rq_check_limits(q, rq))
|
|
return BLK_STS_IOERR;
|
|
|
|
if (rq->rq_disk &&
|
|
should_fail_request(&rq->rq_disk->part0, blk_rq_bytes(rq)))
|
|
return BLK_STS_IOERR;
|
|
|
|
if (blk_queue_io_stat(q))
|
|
blk_account_io_start(rq, true);
|
|
|
|
/*
|
|
* Since we have a scheduler attached on the top device,
|
|
* bypass a potential scheduler on the bottom device for
|
|
* insert.
|
|
*/
|
|
return blk_mq_request_issue_directly(rq, true);
|
|
}
|
|
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.
|
|
*/
|
|
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 sgrp = op_stat_group(req_op(req));
|
|
struct hd_struct *part;
|
|
|
|
part_stat_lock();
|
|
part = req->part;
|
|
part_stat_add(part, sectors[sgrp], bytes >> 9);
|
|
part_stat_unlock();
|
|
}
|
|
}
|
|
|
|
void blk_account_io_done(struct request *req, u64 now)
|
|
{
|
|
/*
|
|
* 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)) {
|
|
const int sgrp = op_stat_group(req_op(req));
|
|
struct hd_struct *part;
|
|
|
|
part_stat_lock();
|
|
part = req->part;
|
|
|
|
update_io_ticks(part, jiffies);
|
|
part_stat_inc(part, ios[sgrp]);
|
|
part_stat_add(part, nsecs[sgrp], now - req->start_time_ns);
|
|
part_stat_add(part, time_in_queue, nsecs_to_jiffies64(now - req->start_time_ns));
|
|
part_dec_in_flight(req->q, part, rq_data_dir(req));
|
|
|
|
hd_struct_put(part);
|
|
part_stat_unlock();
|
|
}
|
|
}
|
|
|
|
void blk_account_io_start(struct request *rq, bool new_io)
|
|
{
|
|
struct hd_struct *part;
|
|
int rw = rq_data_dir(rq);
|
|
|
|
if (!blk_do_io_stat(rq))
|
|
return;
|
|
|
|
part_stat_lock();
|
|
|
|
if (!new_io) {
|
|
part = rq->part;
|
|
part_stat_inc(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_inc_in_flight(rq->q, part, rw);
|
|
rq->part = part;
|
|
}
|
|
|
|
update_io_ticks(part, jiffies);
|
|
|
|
part_stat_unlock();
|
|
}
|
|
|
|
/*
|
|
* Steal bios from a request and add them to a bio list.
|
|
* The request must not have been partially completed before.
|
|
*/
|
|
void blk_steal_bios(struct bio_list *list, struct request *rq)
|
|
{
|
|
if (rq->bio) {
|
|
if (list->tail)
|
|
list->tail->bi_next = rq->bio;
|
|
else
|
|
list->head = rq->bio;
|
|
list->tail = rq->biotail;
|
|
|
|
rq->bio = NULL;
|
|
rq->biotail = NULL;
|
|
}
|
|
|
|
rq->__data_len = 0;
|
|
}
|
|
EXPORT_SYMBOL_GPL(blk_steal_bios);
|
|
|
|
/**
|
|
* blk_update_request - Special helper function for request stacking drivers
|
|
* @req: the request being processed
|
|
* @error: block status code
|
|
* @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.
|
|
*
|
|
* Note:
|
|
* The RQF_SPECIAL_PAYLOAD flag is ignored on purpose in both
|
|
* blk_rq_bytes() and in blk_update_request().
|
|
*
|
|
* Return:
|
|
* %false - this request doesn't have any more data
|
|
* %true - this request has more data
|
|
**/
|
|
bool blk_update_request(struct request *req, blk_status_t error,
|
|
unsigned int nr_bytes)
|
|
{
|
|
int total_bytes;
|
|
|
|
trace_block_rq_complete(req, blk_status_to_errno(error), nr_bytes);
|
|
|
|
if (!req->bio)
|
|
return false;
|
|
|
|
if (unlikely(error && !blk_rq_is_passthrough(req) &&
|
|
!(req->rq_flags & RQF_QUIET)))
|
|
print_req_error(req, error);
|
|
|
|
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;
|
|
|
|
/* Completion has already been traced */
|
|
bio_clear_flag(bio, BIO_TRACE_COMPLETION);
|
|
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;
|
|
}
|
|
|
|
req->__data_len -= total_bytes;
|
|
|
|
/* update sector only for requests with clear definition of sector */
|
|
if (!blk_rq_is_passthrough(req))
|
|
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 (!(req->rq_flags & RQF_SPECIAL_PAYLOAD)) {
|
|
/*
|
|
* 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);
|
|
|
|
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);
|
|
else if (bio_op(bio) == REQ_OP_DISCARD)
|
|
rq->nr_phys_segments = 1;
|
|
|
|
rq->__data_len = bio->bi_iter.bi_size;
|
|
rq->bio = rq->biotail = bio;
|
|
|
|
if (bio->bi_disk)
|
|
rq->rq_disk = bio->bi_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 (queue_is_mq(q) && q->mq_ops->busy)
|
|
return q->mq_ops->busy(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->__sector = blk_rq_pos(src);
|
|
dst->__data_len = blk_rq_bytes(src);
|
|
if (src->rq_flags & RQF_SPECIAL_PAYLOAD) {
|
|
dst->rq_flags |= RQF_SPECIAL_PAYLOAD;
|
|
dst->special_vec = src->special_vec;
|
|
}
|
|
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_mod_delayed_work_on(int cpu, struct delayed_work *dwork,
|
|
unsigned long delay)
|
|
{
|
|
return mod_delayed_work_on(cpu, kblockd_workqueue, dwork, delay);
|
|
}
|
|
EXPORT_SYMBOL(kblockd_mod_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->mq_list);
|
|
INIT_LIST_HEAD(&plug->cb_list);
|
|
plug->rq_count = 0;
|
|
plug->multiple_queues = false;
|
|
|
|
/*
|
|
* 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 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)
|
|
{
|
|
flush_plug_callbacks(plug, from_schedule);
|
|
|
|
if (!list_empty(&plug->mq_list))
|
|
blk_mq_flush_plug_list(plug, from_schedule);
|
|
}
|
|
|
|
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);
|
|
|
|
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");
|
|
|
|
blk_requestq_cachep = kmem_cache_create("request_queue",
|
|
sizeof(struct request_queue), 0, SLAB_PANIC, NULL);
|
|
|
|
#ifdef CONFIG_DEBUG_FS
|
|
blk_debugfs_root = debugfs_create_dir("block", NULL);
|
|
#endif
|
|
|
|
return 0;
|
|
}
|