nvme: simplify error logic in nvme_validate_ns()

We only should remove namespaces when we get fatal error back from
the device or when the namespace IDs have changed.
So instead of painfully masking out error numbers which might indicate
that the error should be ignored we could use an NVME status code
to indicated when the namespace should be removed.
That simplifies the final logic and makes it less error-prone.
Signed-off-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Keith Busch <kbusch@kernel.org>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Reviewed-by: Daniel Wagner <dwagner@suse.de>
Signed-off-by: Christoph Hellwig <hch@lst.de>

drivers/nvme/host/core.c

@@ -1440,7 +1440,7 @@ static int nvme_identify_ns(struct nvme_ctrl *ctrl, unsigned nsid,
 		goto out_free_id;
 	}
 
-	error = -ENODEV;
+	error = NVME_SC_INVALID_NS | NVME_SC_DNR;
 	if ((*id)->ncap == 0) /* namespace not allocated or attached */
 		goto out_free_id;
 
@@ -4038,7 +4038,7 @@ static void nvme_ns_remove_by_nsid(struct nvme_ctrl *ctrl, u32 nsid)
 static void nvme_validate_ns(struct nvme_ns *ns, struct nvme_ns_ids *ids)
 {
 	struct nvme_id_ns *id;
-	int ret = -ENODEV;
+	int ret = NVME_SC_INVALID_NS | NVME_SC_DNR;
 
 	if (test_bit(NVME_NS_DEAD, &ns->flags))
 		goto out;
@@ -4047,7 +4047,7 @@ static void nvme_validate_ns(struct nvme_ns *ns, struct nvme_ns_ids *ids)
 	if (ret)
 		goto out;
 
-	ret = -ENODEV;
+	ret = NVME_SC_INVALID_NS | NVME_SC_DNR;
 	if (!nvme_ns_ids_equal(&ns->head->ids, ids)) {
 		dev_err(ns->ctrl->device,
 			"identifiers changed for nsid %d\n", ns->head->ns_id);
@@ -4065,7 +4065,7 @@ static void nvme_validate_ns(struct nvme_ns *ns, struct nvme_ns_ids *ids)
 	 *
 	 * TODO: we should probably schedule a delayed retry here.
 	 */
-	if (ret && ret != -ENOMEM && !(ret > 0 && !(ret & NVME_SC_DNR)))
+	if (ret > 0 && (ret & NVME_SC_DNR))
 		nvme_ns_remove(ns);
 }