[PATCH AUTOSEL 5.8 70/72] nvme-multipath: do not fall back to __nvme_find_path() for non-optimized paths

Sasha Levin
2020-08-08T23:48:46Z

From: Hannes Reinecke <hare@suse.de>

[ Upstream commit fbd6a42d8932e172921c7de10468a2e12c34846b ]

When nvme_round_robin_path() finds a valid namespace we should be using it;
falling back to __nvme_find_path() for non-optimized paths will cause the
result from nvme_round_robin_path() to be ignored for non-optimized paths.

Fixes: 75c10e732724 ("nvme-multipath: round-robin I/O policy")
Signed-off-by: Martin Wilck <mwilck@suse.com>
Signed-off-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/nvme/host/multipath.c | 11 +++++++----
1 file changed, 7 insertions(+), 4 deletions(-)

diff --git a/drivers/nvme/host/multipath.c b/drivers/nvme/host/multipath.c
index fe8f7f123fac7..57d51148e71b6 100644
--- a/drivers/nvme/host/multipath.c
+++ b/drivers/nvme/host/multipath.c
@@ -272,10 +272,13 @@ inline struct nvme_ns *nvme_find_path(struct nvme_ns_head *head)
struct nvme_ns *ns;

ns = srcu_dereference(head->current_path[node], &head->srcu);
- if (READ_ONCE(head->subsys->iopolicy) == NVME_IOPOLICY_RR && ns)
- ns = nvme_round_robin_path(head, node, ns);
- if (unlikely(!ns || !nvme_path_is_optimized(ns)))
- ns = __nvme_find_path(head, node);
+ if (unlikely(!ns))
+ return __nvme_find_path(head, node);
+
+ if (READ_ONCE(head->subsys->iopolicy) == NVME_IOPOLICY_RR)
+ return nvme_round_robin_path(head, node, ns);
+ if (unlikely(!nvme_path_is_optimized(ns)))
+ return __nvme_find_path(head, node);
return ns;
}

--
2.25.1