[PATCH AUTOSEL 6.8 45/52] nvme: find numa distance only if controller has valid numa id

[Sasha Levin]

From: Nilay Shroff <nilay@xxxxxxxxxxxxx>

[ Upstream commit 863fe60ed27f2c85172654a63c5b827e72c8b2e6 ]

On system where native nvme multipath is configured and iopolicy
is set to numa but the nvme controller numa node id is undefined
or -1 (NUMA_NO_NODE) then avoid calculating node distance for
finding optimal io path. In such case we may access numa distance
table with invalid index and that may potentially refer to incorrect
memory. So this patch ensures that if the nvme controller numa node
id is -1 then instead of calculating node distance for finding optimal
io path, we set the numa node distance of such controller to default 10
(LOCAL_DISTANCE).

Link: https://lore.kernel.org/all/20240413090614.678353-1-nilay@xxxxxxxxxxxxx/
Signed-off-by: Nilay Shroff <nilay@xxxxxxxxxxxxx>
Reviewed-by: Christoph Hellwig <hch@xxxxxx>
Reviewed-by: Sagi Grimberg <sagi@xxxxxxxxxxx>
Reviewed-by: Chaitanya Kulkarni <kch@xxxxxxxxxx>
Signed-off-by: Keith Busch <kbusch@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 drivers/nvme/host/multipath.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/nvme/host/multipath.c b/drivers/nvme/host/multipath.c
index 74de1e64aeead..75386d3e0f981 100644
--- a/drivers/nvme/host/multipath.c
+++ b/drivers/nvme/host/multipath.c
@@ -247,7 +247,8 @@ static struct nvme_ns *__nvme_find_path(struct nvme_ns_head *head, int node)
 		if (nvme_path_is_disabled(ns))
 			continue;
 
-		if (READ_ONCE(head->subsys->iopolicy) == NVME_IOPOLICY_NUMA)
+		if (ns->ctrl->numa_node != NUMA_NO_NODE &&
+		    READ_ONCE(head->subsys->iopolicy) == NVME_IOPOLICY_NUMA)
 			distance = node_distance(node, ns->ctrl->numa_node);
 		else
 			distance = LOCAL_DISTANCE;
-- 
2.43.0