Please, apply the following two upstream commits (attached) (in this order): d567572906d9 nvme: unlink head after removing last namespace ac262508daa8 nvme: release namespace head reference on error
TO: v5.4, v5.5, v5.6, v5.7 These commits are present in v5.8 and apply cleanly to the above.
Reason: These fix a potential crash or malfunction when an nvme namespace is deleted and then a new namespace with the same nsid is created before the old ns_head for this nsid is gone.
The first commit prevents the new namespace from being matched by nvme_init_ns_head() with the old ns_head causing ID mismatch and consequently a failure to initialize the new namespace.
The second commit prevents ns_head refcount imbalance in case nvme_init_ns_head() detects an ID mismatch, and consequently a potential crash later.