From: "Chunguang.xu" <chunguang.xu@shopee.com>

Now spdk will change UUID of ns while restarted if we have not
specified one. At this time, while host try to reconnected to target,
as UUID have changed, we will remove the old ns, but not add the ns
with the new UUID. As a result ctrl with no ns, and we need to
disconnect and connect to get the new ns. Here try to add ns with the
new UUID automatically.

Signed-off-by: Chunguang.xu <chunguang.xu@shopee.com>
---
 drivers/nvme/host/core.c | 45 ++++++++++++++++++----------------------
 1 file changed, 20 insertions(+), 25 deletions(-)

diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
index 855b42c92284..425f59fc80d5 100644
--- a/drivers/nvme/host/core.c
+++ b/drivers/nvme/host/core.c
@@ -3991,28 +3991,6 @@ 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_info *info)
-{
-	int ret = NVME_SC_INVALID_NS | NVME_STATUS_DNR;
-
-	if (!nvme_ns_ids_equal(&ns->head->ids, &info->ids)) {
-		dev_err(ns->ctrl->device,
-			"identifiers changed for nsid %d\n", ns->head->ns_id);
-		goto out;
-	}
-
-	ret = nvme_update_ns_info(ns, info);
-out:
-	/*
-	 * Only remove the namespace if we got a fatal error back from the
-	 * device, otherwise ignore the error and just move on.
-	 *
-	 * TODO: we should probably schedule a delayed retry here.
-	 */
-	if (ret > 0 && (ret & NVME_STATUS_DNR))
-		nvme_ns_remove(ns);
-}
-
 static void nvme_scan_ns(struct nvme_ctrl *ctrl, unsigned nsid)
 {
 	struct nvme_ns_info info = { .nsid = nsid };
@@ -4051,11 +4029,28 @@ static void nvme_scan_ns(struct nvme_ctrl *ctrl, unsigned nsid)
 
 	ns = nvme_find_get_ns(ctrl, nsid);
 	if (ns) {
-		nvme_validate_ns(ns, &info);
+		if (!nvme_ns_ids_equal(&ns->head->ids, &info.ids)) {
+			dev_err(ns->ctrl->device,
+				"identifiers changed for nsid %d\n", ns->head->ns_id);
+			nvme_ns_remove(ns);
+			nvme_put_ns(ns);
+			goto alloc;
+		}
+
+		ret = nvme_update_ns_info(ns, &info);
+		/*
+		 * Only remove the namespace if we got a fatal error back from the
+		 * device, otherwise ignore the error and just move on.
+		 *
+		 * TODO: we should probably schedule a delayed retry here.
+		 */
+		if (ret > 0 && (ret & NVME_STATUS_DNR))
+			nvme_ns_remove(ns);
 		nvme_put_ns(ns);
-	} else {
-		nvme_alloc_ns(ctrl, &info);
+		return;
 	}
+ alloc:
+	nvme_alloc_ns(ctrl, &info);
 }
 
 /**
-- 
2.25.1