From e5d8de32cc02a259e1a237ab57cba00f2930fa6a Mon Sep 17 00:00:00 2001 From: Mike Snitzer Date: Thu, 28 May 2015 15:12:52 -0400 Subject: [PATCH] dm: fix false warning in free_rq_clone() for unmapped requests When stacking request-based dm device on non blk-mq device and device-mapper target could not map the request (error target is used, multipath target with all paths down, etc), the WARN_ON_ONCE() in free_rq_clone() will trigger when it shouldn't. The warning was added by commit aa6df8d ("dm: fix free_rq_clone() NULL pointer when requeueing unmapped request"). But free_rq_clone() with clone->q == NULL is valid usage for the case where dm_kill_unmapped_request() initiates request cleanup. Fix this false warning by just removing the WARN_ON -- it only generated false positives and was never useful in catching the intended case (completing clone request not being mapped e.g. clone->q being NULL). Fixes: aa6df8d ("dm: fix free_rq_clone() NULL pointer when requeueing unmapped request") Reported-by: Bart Van Assche Reported-by: Jun'ichi Nomura Signed-off-by: Mike Snitzer --- drivers/md/dm.c | 8 +++----- 1 file changed, 3 insertions(+), 5 deletions(-) diff --git a/drivers/md/dm.c b/drivers/md/dm.c index 1badfb250a18..e24069aaeb18 100644 --- a/drivers/md/dm.c +++ b/drivers/md/dm.c @@ -1082,13 +1082,11 @@ static void rq_completed(struct mapped_device *md, int rw, bool run_queue) dm_put(md); } -static void free_rq_clone(struct request *clone, bool must_be_mapped) +static void free_rq_clone(struct request *clone) { struct dm_rq_target_io *tio = clone->end_io_data; struct mapped_device *md = tio->md; - WARN_ON_ONCE(must_be_mapped && !clone->q); - blk_rq_unprep_clone(clone); if (md->type == DM_TYPE_MQ_REQUEST_BASED) @@ -1132,7 +1130,7 @@ static void dm_end_request(struct request *clone, int error) rq->sense_len = clone->sense_len; } - free_rq_clone(clone, true); + free_rq_clone(clone); if (!rq->q->mq_ops) blk_end_request_all(rq, error); else @@ -1151,7 +1149,7 @@ static void dm_unprep_request(struct request *rq) } if (clone) - free_rq_clone(clone, false); + free_rq_clone(clone); } /* -- 2.39.2