From: Keith Busch Date: Mon, 12 Jan 2015 20:04:06 +0000 (-0500) Subject: block: keep established cmd_flags when cloning into a blk-mq request X-Git-Url: http://drtracing.org/?a=commitdiff_plain;h=77a086890173c0958515f7322880e4680cf12f8e;p=deliverable%2Flinux.git block: keep established cmd_flags when cloning into a blk-mq request blk_mq_alloc_request() may establish REQ_MQ_INFLIGHT in addition to incrementing the hctx->nr_active count. Any cmd_flags that are established in the newly allocated clone request must be preserved in addition to the cmd_flags that are later copied over from the original request as part of blk_rq_prep_clone(). Otherwise, if REQ_MQ_INFLIGHT isn't set in the clone request the hctx->nr_active count won't get decremented via blk_mq_free_request(). The only consumer of blk_rq_prep_clone() is request-based DM, which uses blk_rq_init() prior to calling blk_rq_prep_clone() for the non-blk-mq case. Given the cloned request's cmd_flags will be 0 it is safe to OR them with the original request's cmd_flags for both the non-blk-mq and blk-mq cases. Reported-by: Bart Van Assche Signed-off-by: Keith Busch Signed-off-by: Mike Snitzer Signed-off-by: Jens Axboe --- diff --git a/block/blk-core.c b/block/blk-core.c index c81f02cd17d4..b5e0cc381458 100644 --- a/block/blk-core.c +++ b/block/blk-core.c @@ -2914,7 +2914,7 @@ EXPORT_SYMBOL_GPL(blk_rq_unprep_clone); static void __blk_rq_prep_clone(struct request *dst, struct request *src) { dst->cpu = src->cpu; - dst->cmd_flags = (src->cmd_flags & REQ_CLONE_MASK) | REQ_NOMERGE; + dst->cmd_flags |= (src->cmd_flags & REQ_CLONE_MASK) | REQ_NOMERGE; dst->cmd_type = src->cmd_type; dst->__sector = blk_rq_pos(src); dst->__data_len = blk_rq_bytes(src);