netfs: Make netfs_put_request() handle a NULL pointer

Make netfs_put_request() just return if given a NULL request pointer.

Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
cc: linux-cachefs@redhat.com
cc: linux-fsdevel@vger.kernel.org
cc: linux-mm@kvack.org

fs/netfs/objects.c

@@ -106,19 +106,22 @@ static void netfs_free_request(struct work_struct *work)
 void netfs_put_request(struct netfs_io_request *rreq, bool was_async,
 		       enum netfs_rreq_ref_trace what)
 {
-	unsigned int debug_id = rreq->debug_id;
+	unsigned int debug_id;
 	bool dead;
 	int r;
 
-	dead = __refcount_dec_and_test(&rreq->ref, &r);
-	trace_netfs_rreq_ref(debug_id, r - 1, what);
-	if (dead) {
-		if (was_async) {
-			rreq->work.func = netfs_free_request;
-			if (!queue_work(system_unbound_wq, &rreq->work))
-				BUG();
-		} else {
-			netfs_free_request(&rreq->work);
+	if (rreq) {
+		debug_id = rreq->debug_id;
+		dead = __refcount_dec_and_test(&rreq->ref, &r);
+		trace_netfs_rreq_ref(debug_id, r - 1, what);
+		if (dead) {
+			if (was_async) {
+				rreq->work.func = netfs_free_request;
+				if (!queue_work(system_unbound_wq, &rreq->work))
+					BUG();
+			} else {
+				netfs_free_request(&rreq->work);
+			}
 		}
 	}
 }