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| author |   Ming Lei <ming.lei@redhat.com> | 2019-08-27 19:01:46 +0800 |
|---|---|---|
| committer |   Jens Axboe <axboe@kernel.dk> | 2019-08-27 10:40:20 -0600 |
| commit | c6ba933358f0d7a6a042b894dba20cc70396a6d3 (patch) | |
| tree | e5d7c3e7fadb316f744edc706a3b8df14a4157aa /block/blk-mq.c | |
| parent | block: don't hold q->sysfs_lock in elevator_init_mq (diff) | |
| download | linux-dev-c6ba933358f0d7a6a042b894dba20cc70396a6d3.tar.xz linux-dev-c6ba933358f0d7a6a042b894dba20cc70396a6d3.zip | |
blk-mq: don't hold q->sysfs_lock in blk_mq_map_swqueue
blk_mq_map_swqueue() is called from blk_mq_init_allocated_queue()
and blk_mq_update_nr_hw_queues(). For the former caller, the kobject
isn't exposed to userspace yet. For the latter caller, hctx sysfs entries
and debugfs are un-registered before updating nr_hw_queues.
On the other hand, commit 2f8f1336a48b ("blk-mq: always free hctx after
request queue is freed") moves freeing hctx into queue's release
handler, so there won't be race with queue release path too.
So don't hold q->sysfs_lock in blk_mq_map_swqueue().
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Hannes Reinecke <hare@suse.com>
Cc: Greg KH <gregkh@linuxfoundation.org>
Cc: Mike Snitzer <snitzer@redhat.com>
Cc: Bart Van Assche <bvanassche@acm.org>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'block/blk-mq.c')
| -rw-r--r-- | block/blk-mq.c | 7 |
1 files changed, 0 insertions, 7 deletions
diff --git a/block/blk-mq.c b/block/blk-mq.c index 509f69fdfcf2..cf768d0c2950 100644 --- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -2456,11 +2456,6 @@ static void blk_mq_map_swqueue(struct request_queue *q) struct blk_mq_ctx *ctx; struct blk_mq_tag_set *set = q->tag_set; - /* - * Avoid others reading imcomplete hctx->cpumask through sysfs - */ - mutex_lock(&q->sysfs_lock); - queue_for_each_hw_ctx(q, hctx, i) { cpumask_clear(hctx->cpumask); hctx->nr_ctx = 0; @@ -2521,8 +2516,6 @@ static void blk_mq_map_swqueue(struct request_queue *q) HCTX_TYPE_DEFAULT, i); } - mutex_unlock(&q->sysfs_lock); - queue_for_each_hw_ctx(q, hctx, i) { /* * If no software queues are mapped to this hardware queue, |