nvme-multipath: fix leak on try_module_get failure

We need to fall back to the synchronous removal if we can't get a
reference on the module needed for the deferred removal.

Fixes: 6218863 ("nvme-multipath: introduce delayed removal of the multipath head node")
Reviewed-by: Nilay Shroff <[email protected]>
Reviewed-by: John Garry <[email protected]>
Reviewed-by: Christoph Hellwig <[email protected]>
Signed-off-by: Keith Busch <[email protected]>

Author: keithbusch

drivers/nvme/host/multipath.c

@@ -1310,13 +1310,11 @@ void nvme_mpath_remove_disk(struct nvme_ns_head *head)
 	if (!list_empty(&head->list))
 		goto out;
 
-	if (head->delayed_removal_secs) {
-		/*
-		 * Ensure that no one could remove this module while the head
-		 * remove work is pending.
-		 */
-		if (!try_module_get(THIS_MODULE))
-			goto out;
+	/*
+	 * Ensure that no one could remove this module while the head
+	 * remove work is pending.
+	 */
+	if (head->delayed_removal_secs && try_module_get(THIS_MODULE)) {
 		mod_delayed_work(nvme_wq, &head->remove_work,
 				head->delayed_removal_secs * HZ);
 	} else {