From: Ming Lei ming.lei@redhat.com
stable inclusion from linux-4.19.176 commit 6ff18507a7c165b90f1fe51822c65d10265f5714
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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 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 Signed-off-by: Jack Wang jinpu.wang@cloud.ionos.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Yang Yingliang yangyingliang@huawei.com Signed-off-by: Cheng Jian cj.chengjian@huawei.com --- block/blk-mq.c | 7 ------- 1 file changed, 7 deletions(-)
diff --git a/block/blk-mq.c b/block/blk-mq.c index 795ed40ce415..b5c2a4f65402 100644 --- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -2417,11 +2417,6 @@ 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; @@ -2455,8 +2450,6 @@ static void blk_mq_map_swqueue(struct request_queue *q) 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,