nvme-multipath: fix ANA state updates when a namespace is not present

nvme_update_ana_state() has a deficiency that results in a failure to
properly update the ana state for a namespace in the following case:

  NSIDs in ctrl->namespaces:	1, 3,    4
  NSIDs in desc->nsids:		1, 2, 3, 4

Loop iteration 0:
    ns index = 0, n = 0, ns->head->ns_id = 1, nsid = 1, MATCH.
Loop iteration 1:
    ns index = 1, n = 1, ns->head->ns_id = 3, nsid = 2, NO MATCH.
Loop iteration 2:
    ns index = 2, n = 2, ns->head->ns_id = 4, nsid = 4, MATCH.

Where the update to the ANA state of NSID 3 is missed.  To fix this
increment n and retry the update with the same ns when ns->head->ns_id is
higher than nsid,

Signed-off-by: Anton Eidelman <anton@lightbitslabs.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>

Author: ttooxxaa

drivers/nvme/host/multipath.c

@@ -600,14 +600,17 @@ static int nvme_update_ana_state(struct nvme_ctrl *ctrl,
 
 	down_read(&ctrl->namespaces_rwsem);
 	list_for_each_entry(ns, &ctrl->namespaces, list) {
-		unsigned nsid = le32_to_cpu(desc->nsids[n]);
-
+		unsigned nsid;
+again:
+		nsid = le32_to_cpu(desc->nsids[n]);
 		if (ns->head->ns_id < nsid)
 			continue;
 		if (ns->head->ns_id == nsid)
 			nvme_update_ns_ana_state(desc, ns);
 		if (++n == nr_nsids)
 			break;
+		if (ns->head->ns_id > nsid)
+			goto again;
 	}
 	up_read(&ctrl->namespaces_rwsem);
 	return 0;