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, 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_map_swqueue().
Cc: Christoph Hellwig <h...@infradead.org>
Cc: Hannes Reinecke <h...@suse.com>
Cc: Greg KH <gre...@linuxfoundation.org>
Cc: Mike Snitzer <snit...@redhat.com>
Cc: Bart Van Assche <bvanass...@acm.org>
Signed-off-by: Ming Lei <ming....@redhat.com>
---
block/blk-mq.c | 7 -------
1 file changed, 7 deletions(-)
diff --git a/block/blk-mq.c b/block/blk-mq.c
index 6968de9d7402..b0ee0cac737f 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,
--
2.20.1
