diff options
| author | Nilay Shroff <nilay@linux.ibm.com> | 2025-03-04 13:22:36 +0300 |
|---|---|---|
| committer | Jens Axboe <axboe@kernel.dk> | 2025-03-10 16:30:19 +0300 |
| commit | 5e40f4452dc9a3fb44d13bb6bc7032f3911a2675 (patch) | |
| tree | 800af80ece9828aa52ae395163338979ab3132dd | |
| parent | 245618f8e45ff4f79327627b474b563da71c2c75 (diff) | |
| download | linux-5e40f4452dc9a3fb44d13bb6bc7032f3911a2675.tar.xz | |
block: protect read_ahead_kb using q->limits_lock
The bdi->ra_pages could be updated under q->limits_lock because it's
usually calculated from the queue limits by queue_limits_commit_update.
So protect reading/writing the sysfs attribute read_ahead_kb using
q->limits_lock instead of q->sysfs_lock.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Nilay Shroff <nilay@linux.ibm.com>
Link: https://lore.kernel.org/r/20250304102551.2533767-8-nilay@linux.ibm.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
| -rw-r--r-- | block/blk-sysfs.c | 16 | ||||
| -rw-r--r-- | include/linux/blkdev.h | 3 |
2 files changed, 13 insertions, 6 deletions
diff --git a/block/blk-sysfs.c b/block/blk-sysfs.c index 223da196a548..d584461a1d84 100644 --- a/block/blk-sysfs.c +++ b/block/blk-sysfs.c @@ -93,9 +93,9 @@ static ssize_t queue_ra_show(struct gendisk *disk, char *page) { ssize_t ret; - mutex_lock(&disk->queue->sysfs_lock); + mutex_lock(&disk->queue->limits_lock); ret = queue_var_show(disk->bdi->ra_pages << (PAGE_SHIFT - 10), page); - mutex_unlock(&disk->queue->sysfs_lock); + mutex_unlock(&disk->queue->limits_lock); return ret; } @@ -111,12 +111,15 @@ queue_ra_store(struct gendisk *disk, const char *page, size_t count) ret = queue_var_store(&ra_kb, page, count); if (ret < 0) return ret; - - mutex_lock(&q->sysfs_lock); + /* + * ->ra_pages is protected by ->limits_lock because it is usually + * calculated from the queue limits by queue_limits_commit_update. + */ + mutex_lock(&q->limits_lock); memflags = blk_mq_freeze_queue(q); disk->bdi->ra_pages = ra_kb >> (PAGE_SHIFT - 10); + mutex_unlock(&q->limits_lock); blk_mq_unfreeze_queue(q, memflags); - mutex_unlock(&q->sysfs_lock); return ret; } @@ -670,7 +673,8 @@ static struct attribute *queue_attrs[] = { &queue_dma_alignment_entry.attr, /* - * Attributes which are protected with q->sysfs_lock. + * Attributes which require some form of locking other than + * q->sysfs_lock. */ &queue_ra_entry.attr, diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h index 0ee3b5c9388e..3bee1b4858b6 100644 --- a/include/linux/blkdev.h +++ b/include/linux/blkdev.h @@ -571,6 +571,9 @@ struct request_queue { struct mutex elevator_lock; struct mutex sysfs_lock; + /* + * Protects queue limits and also sysfs attribute read_ahead_kb. + */ struct mutex limits_lock; /* |