From 6599c84e4ce6e428180f9958c7c40aa4202d8072 Mon Sep 17 00:00:00 2001 From: Bart Van Assche Date: Tue, 15 Nov 2016 15:34:32 -0800 Subject: [PATCH] dm mpath: do not modify *__clone if blk_mq_alloc_request() fails Purely cleanup, avoids potential for strange coding bugs. But in reality if __multipath_map() fails the caller has no business looking at *__clone. Signed-off-by: Bart Van Assche Signed-off-by: Mike Snitzer --- drivers/md/dm-mpath.c | 15 ++++++++------- 1 file changed, 8 insertions(+), 7 deletions(-) diff --git a/drivers/md/dm-mpath.c b/drivers/md/dm-mpath.c index 373e5e3eec78..0caab4bf3515 100644 --- a/drivers/md/dm-mpath.c +++ b/drivers/md/dm-mpath.c @@ -580,16 +580,17 @@ static int __multipath_map(struct dm_target *ti, struct request *clone, * .request_fn stacked on blk-mq path(s) and * blk-mq stacked on blk-mq path(s). */ - *__clone = blk_mq_alloc_request(bdev_get_queue(bdev), - rq_data_dir(rq), BLK_MQ_REQ_NOWAIT); - if (IS_ERR(*__clone)) { - /* ENOMEM, requeue */ + clone = blk_mq_alloc_request(bdev_get_queue(bdev), + rq_data_dir(rq), BLK_MQ_REQ_NOWAIT); + if (IS_ERR(clone)) { + /* EBUSY, ENODEV or EWOULDBLOCK: requeue */ clear_request_fn_mpio(m, map_context); return r; } - (*__clone)->bio = (*__clone)->biotail = NULL; - (*__clone)->rq_disk = bdev->bd_disk; - (*__clone)->cmd_flags |= REQ_FAILFAST_TRANSPORT; + clone->bio = clone->biotail = NULL; + clone->rq_disk = bdev->bd_disk; + clone->cmd_flags |= REQ_FAILFAST_TRANSPORT; + *__clone = clone; } if (pgpath->pg->ps.type->start_io) -- 2.20.1