Do not modify *__clone if blk_mq_alloc_request() fails. This makes it easier to figure out what is going on if the caller accidentally dereferences *__clone if blk_mq_alloc_request() failed.
Signed-off-by: Bart Van Assche <[email protected]> --- 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 1c97f0e..5c73818 100644 --- a/drivers/md/dm-mpath.c +++ b/drivers/md/dm-mpath.c @@ -582,16 +582,17 @@ 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 = clone; + clone->bio = clone->biotail = NULL; + clone->rq_disk = bdev->bd_disk; + clone->cmd_flags |= REQ_FAILFAST_TRANSPORT; } if (pgpath->pg->ps.type->start_io) -- 2.10.1 -- dm-devel mailing list [email protected] https://www.redhat.com/mailman/listinfo/dm-devel
