From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Bart Van Assche To: Jens Axboe CC: , "Martin K . Petersen" , James Bottomley , Bart Van Assche , Christoph Hellwig , Hannes Reinecke Subject: [PATCH v2 2/5] blk-mq: Make it safe to use RCU to iterate over blk_mq_tag_set.tag_list Date: Mon, 3 Apr 2017 16:22:25 -0700 Message-ID: <20170403232228.11208-3-bart.vanassche@sandisk.com> In-Reply-To: <20170403232228.11208-1-bart.vanassche@sandisk.com> References: <20170403232228.11208-1-bart.vanassche@sandisk.com> MIME-Version: 1.0 Content-Type: text/plain Return-Path: Bart.VanAssche@sandisk.com List-ID: A later patch in this series will namely use RCU to iterate over this list. Signed-off-by: Bart Van Assche Cc: Christoph Hellwig Cc: Hannes Reinecke Cc: Martin K. Petersen Cc: James Bottomley --- block/blk-mq.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/block/blk-mq.c b/block/blk-mq.c index 061fc2cc88d3..8fb983e6e2e4 100644 --- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -2093,6 +2093,8 @@ static void blk_mq_update_tag_set_depth(struct blk_mq_tag_set *set, bool shared) { struct request_queue *q; + lockdep_assert_held(&set->tag_list_lock); + list_for_each_entry(q, &set->tag_list, tag_set_list) { blk_mq_freeze_queue(q); queue_set_hctx_shared(q, shared); @@ -2113,6 +2115,8 @@ static void blk_mq_del_queue_tag_set(struct request_queue *q) blk_mq_update_tag_set_depth(set, false); } mutex_unlock(&set->tag_list_lock); + + synchronize_rcu(); } static void blk_mq_add_queue_tag_set(struct blk_mq_tag_set *set, @@ -2618,6 +2622,8 @@ void blk_mq_update_nr_hw_queues(struct blk_mq_tag_set *set, int nr_hw_queues) { struct request_queue *q; + lockdep_assert_held(&set->tag_list_lock); + if (nr_hw_queues > nr_cpu_ids) nr_hw_queues = nr_cpu_ids; if (nr_hw_queues < 1 || nr_hw_queues == set->nr_hw_queues) -- 2.12.0