nvme-multipath: Early exit if no path is available

[ Upstream commit d1bcf006a9d3d63c1bcb65a993cb13756954cd9c ]

nvme_round_robin_path() should test if the return ns pointer is valid.
nvme_next_ns() will return a NULL pointer if there is no path left.

Fixes: 75c10e732724 ("nvme-multipath: round-robin I/O policy")
Signed-off-by: Daniel Wagner <dwagner@suse.de>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/drivers/nvme/host/multipath.c b/drivers/nvme/host/multipath.c
index 74896be..292e535 100644 (file)
--- a/drivers/nvme/host/multipath.c
+++ b/drivers/nvme/host/multipath.c
@@ -221,7 +221,7 @@ static struct nvme_ns *nvme_round_robin_path(struct nvme_ns_head *head,
        }
 
        for (ns = nvme_next_ns(head, old);
-            ns != old;
+            ns && ns != old;
             ns = nvme_next_ns(head, ns)) {
                if (nvme_path_is_disabled(ns))
                        continue;