From d03f6cdc1fc422accb734c7c07a661a0018d8631 Mon Sep 17 00:00:00 2001 From: Jan Kara Date: Thu, 2 Feb 2017 15:56:51 +0100 Subject: [PATCH] block: Dynamically allocate and refcount backing_dev_info Instead of storing backing_dev_info inside struct request_queue, allocate it dynamically, reference count it, and free it when the last reference is dropped. Currently only request_queue holds the reference but in the following patch we add other users referencing backing_dev_info. Signed-off-by: Jan Kara Signed-off-by: Jens Axboe --- block/blk-core.c | 12 +++++------ block/blk-sysfs.c | 2 +- include/linux/backing-dev-defs.h | 2 ++ include/linux/backing-dev.h | 10 +++++++++- include/linux/blkdev.h | 1 - mm/backing-dev.c | 34 +++++++++++++++++++++++++++++++- 6 files changed, 50 insertions(+), 11 deletions(-) diff --git a/block/blk-core.c b/block/blk-core.c index dcac0352c14c..d2bba4700e65 100644 --- a/block/blk-core.c +++ b/block/blk-core.c @@ -713,7 +713,6 @@ static void blk_rq_timed_out_timer(unsigned long data) 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); @@ -728,17 +727,16 @@ struct request_queue *blk_alloc_queue_node(gfp_t gfp_mask, int node_id) if (!q->bio_split) goto fail_id; - q->backing_dev_info = &q->_backing_dev_info; + q->backing_dev_info = bdi_alloc_node(gfp_mask, node_id); + if (!q->backing_dev_info) + goto fail_split; + 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); @@ -789,7 +787,7 @@ struct request_queue *blk_alloc_queue_node(gfp_t gfp_mask, int node_id) fail_ref: percpu_ref_exit(&q->q_usage_counter); fail_bdi: - bdi_destroy(q->backing_dev_info); + bdi_put(q->backing_dev_info); fail_split: bioset_free(q->bio_split); fail_id: diff --git a/block/blk-sysfs.c b/block/blk-sysfs.c index 05841be1f30f..3e204789b8d3 100644 --- a/block/blk-sysfs.c +++ b/block/blk-sysfs.c @@ -799,7 +799,7 @@ static void blk_release_queue(struct kobject *kobj) container_of(kobj, struct request_queue, kobj); wbt_exit(q); - bdi_exit(q->backing_dev_info); + bdi_put(q->backing_dev_info); blkcg_exit_queue(q); if (q->elevator) { diff --git a/include/linux/backing-dev-defs.h b/include/linux/backing-dev-defs.h index e850e76acaaf..ad955817916d 100644 --- a/include/linux/backing-dev-defs.h +++ b/include/linux/backing-dev-defs.h @@ -10,6 +10,7 @@ #include #include #include +#include struct page; struct device; @@ -144,6 +145,7 @@ struct backing_dev_info { char *name; + struct kref refcnt; /* Reference counter for the structure */ unsigned int capabilities; /* Device capabilities */ unsigned int min_ratio; unsigned int max_ratio, max_prop_frac; diff --git a/include/linux/backing-dev.h b/include/linux/backing-dev.h index 43b93a947e61..efb6ca992d05 100644 --- a/include/linux/backing-dev.h +++ b/include/linux/backing-dev.h @@ -18,7 +18,14 @@ #include int __must_check bdi_init(struct backing_dev_info *bdi); -void bdi_exit(struct backing_dev_info *bdi); + +static inline struct backing_dev_info *bdi_get(struct backing_dev_info *bdi) +{ + kref_get(&bdi->refcnt); + return bdi; +} + +void bdi_put(struct backing_dev_info *bdi); __printf(3, 4) int bdi_register(struct backing_dev_info *bdi, struct device *parent, @@ -29,6 +36,7 @@ void bdi_unregister(struct backing_dev_info *bdi); int __must_check bdi_setup_and_register(struct backing_dev_info *, char *); void bdi_destroy(struct backing_dev_info *bdi); +struct backing_dev_info *bdi_alloc_node(gfp_t gfp_mask, int node_id); void wb_start_writeback(struct bdi_writeback *wb, long nr_pages, bool range_cyclic, enum wb_reason reason); diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h index a75e42de34ab..e77c1039fd0e 100644 --- a/include/linux/blkdev.h +++ b/include/linux/blkdev.h @@ -433,7 +433,6 @@ struct request_queue { struct delayed_work delay_work; struct backing_dev_info *backing_dev_info; - struct backing_dev_info _backing_dev_info; /* * The queue owner gets to use this for whatever they like. diff --git a/mm/backing-dev.c b/mm/backing-dev.c index 3bfed5ab2475..28ce6cf7b2ff 100644 --- a/mm/backing-dev.c +++ b/mm/backing-dev.c @@ -237,6 +237,7 @@ static __init int bdi_class_init(void) bdi_class->dev_groups = bdi_dev_groups; bdi_debug_init(); + return 0; } postcore_initcall(bdi_class_init); @@ -776,6 +777,7 @@ int bdi_init(struct backing_dev_info *bdi) bdi->dev = NULL; + kref_init(&bdi->refcnt); bdi->min_ratio = 0; bdi->max_ratio = 100; bdi->max_prop_frac = FPROP_FRAC_BASE; @@ -791,6 +793,22 @@ int bdi_init(struct backing_dev_info *bdi) } EXPORT_SYMBOL(bdi_init); +struct backing_dev_info *bdi_alloc_node(gfp_t gfp_mask, int node_id) +{ + struct backing_dev_info *bdi; + + bdi = kmalloc_node(sizeof(struct backing_dev_info), + gfp_mask | __GFP_ZERO, node_id); + if (!bdi) + return NULL; + + if (bdi_init(bdi)) { + kfree(bdi); + return NULL; + } + return bdi; +} + int bdi_register(struct backing_dev_info *bdi, struct device *parent, const char *fmt, ...) { @@ -871,12 +889,26 @@ void bdi_unregister(struct backing_dev_info *bdi) } } -void bdi_exit(struct backing_dev_info *bdi) +static void bdi_exit(struct backing_dev_info *bdi) { WARN_ON_ONCE(bdi->dev); wb_exit(&bdi->wb); } +static void release_bdi(struct kref *ref) +{ + struct backing_dev_info *bdi = + container_of(ref, struct backing_dev_info, refcnt); + + bdi_exit(bdi); + kfree(bdi); +} + +void bdi_put(struct backing_dev_info *bdi) +{ + kref_put(&bdi->refcnt, release_bdi); +} + void bdi_destroy(struct backing_dev_info *bdi) { bdi_unregister(bdi);