From c6ba933358f0d7a6a042b894dba20cc70396a6d3 Mon Sep 17 00:00:00 2001 From: Ming Lei Date: Tue, 27 Aug 2019 19:01:46 +0800 Subject: [PATCH] blk-mq: don't hold q->sysfs_lock in blk_mq_map_swqueue 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 Cc: Hannes Reinecke Cc: Greg KH Cc: Mike Snitzer Cc: Bart Van Assche Reviewed-by: Bart Van Assche Signed-off-by: Ming Lei Signed-off-by: Jens Axboe --- block/blk-mq.c | 7 ------- 1 file changed, 7 deletions(-) diff --git a/block/blk-mq.c b/block/blk-mq.c index 509f69f..cf768d0 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, -- 2.7.4