sunrpc: if we're closing down a socket, clear memalloc on it first

[deliverable/linux.git] / net / sunrpc / xprtsock.c

diff --git a/net/sunrpc/xprtsock.c b/net/sunrpc/xprtsock.c
index b142feef0cf46cac77836a6cb460985ee53e9eef..31b856a2935c7207e5ad8824df25a5a15ec3c1e5 100644 (file)
--- a/net/sunrpc/xprtsock.c
+++ b/net/sunrpc/xprtsock.c
@@ -827,6 +827,9 @@ static void xs_reset_transport(struct sock_xprt *transport)
        if (sk == NULL)
                return;
 
+       if (atomic_read(&transport->xprt.swapper))
+               sk_clear_memalloc(sk);
+
        write_lock_bh(&sk->sk_callback_lock);
        transport->inet = NULL;
        transport->sock = NULL;
@@ -1955,39 +1958,50 @@ static void xs_local_connect(struct rpc_xprt *xprt, struct rpc_task *task)
                msleep_interruptible(15000);
 }
 
-#ifdef CONFIG_SUNRPC_SWAP
+#if IS_ENABLED(CONFIG_SUNRPC_SWAP)
 static void xs_set_memalloc(struct rpc_xprt *xprt)
 {
        struct sock_xprt *transport = container_of(xprt, struct sock_xprt,
                        xprt);
 
-       if (xprt->swapper)
+       if (atomic_read(&xprt->swapper))
                sk_set_memalloc(transport->inet);
 }
 
 /**
- * xs_swapper - Tag this transport as being used for swap.
+ * xs_swapper_enable - Tag this transport as being used for swap.
  * @xprt: transport to tag
- * @enable: enable/disable
  *
+ * Take a reference to this transport on behalf of the rpc_clnt, and
+ * optionally mark it for swapping if it wasn't already.
  */
-int xs_swapper(struct rpc_xprt *xprt, int enable)
+int
+xs_swapper_enable(struct rpc_xprt *xprt)
 {
        struct sock_xprt *transport = container_of(xprt, struct sock_xprt,
                        xprt);
-       int err = 0;
 
-       if (enable) {
-               xprt->swapper++;
-               xs_set_memalloc(xprt);
-       } else if (xprt->swapper) {
-               xprt->swapper--;
-               sk_clear_memalloc(transport->inet);
-       }
+       if (atomic_inc_return(&xprt->swapper) == 1)
+               sk_set_memalloc(transport->inet);
+       return 0;
+}
 
-       return err;
+/**
+ * xs_swapper_disable - Untag this transport as being used for swap.
+ * @xprt: transport to tag
+ *
+ * Drop a "swapper" reference to this xprt on behalf of the rpc_clnt. If the
+ * swapper refcount goes to 0, untag the socket as a memalloc socket.
+ */
+void
+xs_swapper_disable(struct rpc_xprt *xprt)
+{
+       struct sock_xprt *transport = container_of(xprt, struct sock_xprt,
+                       xprt);
+
+       if (atomic_dec_and_test(&xprt->swapper))
+               sk_clear_memalloc(transport->inet);
 }
-EXPORT_SYMBOL_GPL(xs_swapper);
 #else
 static void xs_set_memalloc(struct rpc_xprt *xprt)
 {