From: Ming Lei ming.lei@redhat.com
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 (cherry picked from commit c6ba933358f0d7a6a042b894dba20cc70396a6d3) Signed-off-by: Jack Wang jinpu.wang@cloud.ionos.com --- block/blk-mq.c | 7 ------- 1 file changed, 7 deletions(-)
diff --git a/block/blk-mq.c b/block/blk-mq.c index 0df43515ff94..195526b93895 100644 --- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -2324,11 +2324,6 @@ 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; @@ -2362,8 +2357,6 @@ 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,