nvme-multipath: fix logic for non-optimized paths

Handle the special case where we have exactly one optimized path,
which we should keep using in this case.

Fixes: 75c10e7 ("nvme-multipath: round-robin I/O policy")
Signed off-by: Martin Wilck <[email protected]>
Signed-off-by: Hannes Reinecke <[email protected]>
Reviewed-by: Sagi Grimberg <[email protected]>
Signed-off-by: Christoph Hellwig <[email protected]>

Author: mwilck

drivers/nvme/host/multipath.c

@@ -255,6 +255,12 @@ static struct nvme_ns *nvme_round_robin_path(struct nvme_ns_head *head,
 			fallback = ns;
 	}
 
+	/* No optimized path found, re-check the current path */
+	if (!nvme_path_is_disabled(old) &&
+	    old->ana_state == NVME_ANA_OPTIMIZED) {
+		found = old;
+		goto out;
+	}
 	if (!fallback)
 		return NULL;
 	found = fallback;