From: Ming Lei <ming....@redhat.com> commit c6ba933358f0d7a6a042b894dba20cc70396a6d3 upstream.
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 <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> Reviewed-by: Bart Van Assche <bvanass...@acm.org> Signed-off-by: Ming Lei <ming....@redhat.com> Signed-off-by: Jens Axboe <ax...@kernel.dk> Signed-off-by: Jack Wang <jinpu.w...@cloud.ionos.com> Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org> --- block/blk-mq.c | 7 ------- 1 file changed, 7 deletions(-) --- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -2324,11 +2324,6 @@ static void blk_mq_map_swqueue(struct re 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; @@ -2362,8 +2357,6 @@ static void blk_mq_map_swqueue(struct re hctx->ctxs[hctx->nr_ctx++] = ctx; } - mutex_unlock(&q->sysfs_lock); - queue_for_each_hw_ctx(q, hctx, i) { /* * If no software queues are mapped to this hardware queue,