nvme: release namespace head reference on error

commit ac26250 upstream.

If a namespace identification does not match the subsystem's head for
that NSID, release the reference that was taken when the matching head
was initially found.

Signed-off-by: Keith Busch <kbusch@kernel.org>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/nvme/host/core.c

@@ -3467,6 +3467,7 @@ static int nvme_init_ns_head(struct nvme_ns *ns, unsigned nsid,
 				"IDs don't match for shared namespace %d\n",
 					nsid);
 			ret = -EINVAL;
+			nvme_put_ns_head(head);
 			goto out_unlock;
 		}
 	}