From a12bffebc0c9d6a5851f062aaea3aa7c4adc6042 Mon Sep 17 00:00:00 2001 From: Filippo Muzzini Date: Thu, 31 May 2018 15:23:11 +0200 Subject: [PATCH] block, bfq: remove wrong lock in bfq_requests_merged In bfq_requests_merged(), there is a deadlock because the lock on bfqq->bfqd->lock is held by the calling function, but the code of this function tries to grab the lock again. This deadlock is currently hidden by another bug (fixed by next commit for this source file), which causes the body of bfq_requests_merged() to be never executed. This commit removes the deadlock by removing the lock/unlock pair. Signed-off-by: Filippo Muzzini Signed-off-by: Paolo Valente Signed-off-by: Jens Axboe --- block/bfq-iosched.c | 2 -- 1 file changed, 2 deletions(-) diff --git a/block/bfq-iosched.c b/block/bfq-iosched.c index b622e73a326a..02dd4c836936 100644 --- a/block/bfq-iosched.c +++ b/block/bfq-iosched.c @@ -1847,7 +1847,6 @@ static void bfq_requests_merged(struct request_queue *q, struct request *rq, if (!RB_EMPTY_NODE(&rq->rb_node)) goto end; - spin_lock_irq(&bfqq->bfqd->lock); /* * If next and rq belong to the same bfq_queue and next is older @@ -1872,7 +1871,6 @@ static void bfq_requests_merged(struct request_queue *q, struct request *rq, bfq_remove_request(q, next); bfqg_stats_update_io_remove(bfqq_group(bfqq), next->cmd_flags); - spin_unlock_irq(&bfqq->bfqd->lock); end: bfqg_stats_update_io_merged(bfqq_group(bfqq), next->cmd_flags); }