blk_mq_realloc_hw_ctxs() 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, sysfs/debugfs
is 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_realloc_hw_ctxs().
Cc: Christoph Hellwig <hch@xxxxxxxxxxxxx>
Cc: Hannes Reinecke <hare@xxxxxxxx>
Cc: Greg KH <gregkh@xxxxxxxxxxxxxxxxxxx>
Cc: Mike Snitzer <snitzer@xxxxxxxxxx>
Cc: Bart Van Assche <bvanassche@xxxxxxx>
Signed-off-by: Ming Lei <ming.lei@xxxxxxxxxx>
---
block/blk-mq.c | 3 ---
1 file changed, 3 deletions(-)
diff --git a/block/blk-mq.c b/block/blk-mq.c
index b0ee0cac737f..d4c8692aca1f 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -2768,8 +2768,6 @@ static void blk_mq_realloc_hw_ctxs(struct blk_mq_tag_set *set,
int i, j, end;
struct blk_mq_hw_ctx **hctxs = q->queue_hw_ctx;
- /* protect against switching io scheduler */
- mutex_lock(&q->sysfs_lock);
for (i = 0; i < set->nr_hw_queues; i++) {
int node;
struct blk_mq_hw_ctx *hctx;
@@ -2820,7 +2818,6 @@ static void blk_mq_realloc_hw_ctxs(struct blk_mq_tag_set *set,
hctxs[j] = NULL;
}
}
- mutex_unlock(&q->sysfs_lock);
}
/*
--
2.20.1
