From 88994acafd96dbb9f07d293e60b882b7f1654702 Mon Sep 17 00:00:00 2001 From: Martin Wilck Date: Thu, 6 Aug 2020 15:19:31 +0200 Subject: [PATCH] nvme: multipath: round-robin: fix single non-optimized path case [ Upstream commit 93eb0381e13d249a18ed4aae203291ff977e7ffb ] If there's only one usable, non-optimized path, nvme_round_robin_path() returns NULL, which is wrong. Fix it by falling back to "old", like in the single optimized path case. Also, if the active path isn't changed, there's no need to re-assign the pointer. Fixes: 3f6e3246db0e ("nvme-multipath: fix logic for non-optimized paths") Signed-off-by: Martin Wilck Signed-off-by: Martin George Reviewed-by: Keith Busch Signed-off-by: Sagi Grimberg Signed-off-by: Jens Axboe Signed-off-by: Sasha Levin --- drivers/nvme/host/multipath.c | 15 ++++++++++----- 1 file changed, 10 insertions(+), 5 deletions(-) diff --git a/drivers/nvme/host/multipath.c b/drivers/nvme/host/multipath.c index 484aad0d0c9c..0a458f788088 100644 --- a/drivers/nvme/host/multipath.c +++ b/drivers/nvme/host/multipath.c @@ -249,12 +249,17 @@ static struct nvme_ns *nvme_round_robin_path(struct nvme_ns_head *head, fallback = ns; } - /* No optimized path found, re-check the current path */ + /* + * The loop above skips the current path for round-robin semantics. + * Fall back to the current path if either: + * - no other optimized path found and current is optimized, + * - no other usable path found and current is usable. + */ if (!nvme_path_is_disabled(old) && - old->ana_state == NVME_ANA_OPTIMIZED) { - found = old; - goto out; - } + (old->ana_state == NVME_ANA_OPTIMIZED || + (!fallback && old->ana_state == NVME_ANA_NONOPTIMIZED))) + return old; + if (!fallback) return NULL; found = fallback; -- 2.43.0