[PATCH] RPC: separate TCP and UDP transport connection logic

 Create separate connection worker functions for managing UDP and TCP
 transport sockets.  This eliminates several dependencies on "xprt->stream".

 Test-plan:
 Destructive testing (unplugging the network temporarily).  Connectathon with
 v2, v3, and v4.

 Version: Thu, 11 Aug 2005 16:08:18 -0400

 Signed-off-by: Chuck Lever <cel@netapp.com>
 Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

1 files changed, 91 insertions, 73 deletions

diff --git a/net/sunrpc/xprtsock.c b/net/sunrpc/xprtsock.c
index 70a772d7a796..f91529787b9b 100644
--- a/net/sunrpc/xprtsock.c
+++ b/net/sunrpc/xprtsock.c
@@ -836,102 +836,118 @@ static int xs_bindresvport(struct rpc_xprt *xprt, struct socket *sock)
         return err;
 }
 
-static struct socket *xs_create(struct rpc_xprt *xprt, int proto, int resvport)
+/**
+ * xs_udp_connect_worker - set up a UDP socket
+ * @args: RPC transport to connect
+ *
+ * Invoked by a work queue tasklet.
+ */
+static void xs_udp_connect_worker(void *args)
 {
-        struct socket *sock;
-        int type, err;
-
-        dprintk("RPC:      xs_create(%s %d)\n",
-                           (proto == IPPROTO_UDP)? "udp" : "tcp", proto);
+        struct rpc_xprt *xprt = (struct rpc_xprt *) args;
+        struct socket *sock = xprt->sock;
+        int err, status = -EIO;
 
-        type = (proto == IPPROTO_UDP)? SOCK_DGRAM : SOCK_STREAM;
+        if (xprt->shutdown || xprt->addr.sin_port == 0)
+                goto out;
 
-        if ((err = sock_create_kern(PF_INET, type, proto, &sock)) < 0) {
-                dprintk("RPC:      can't create socket (%d).\n", -err);
-                return NULL;
-        }
+        dprintk("RPC:      xs_udp_connect_worker for xprt %p\n", xprt);
 
-        /* If the caller has the capability, bind to a reserved port */
-        if (resvport && xs_bindresvport(xprt, sock) < 0)
-                goto failed;
+        /* Start by resetting any existing state */
+        xs_close(xprt);
 
-        return sock;
+        if ((err = sock_create_kern(PF_INET, SOCK_DGRAM, IPPROTO_UDP, &sock)) < 0) {
+                dprintk("RPC:      can't create UDP transport socket (%d).\n", -err);
+                goto out;
+        }
 
-failed:
-        sock_release(sock);
-        return NULL;
-}
+        if (xprt->resvport && xs_bindresvport(xprt, sock) < 0) {
+                sock_release(sock);
+                goto out;
+        }
 
-static void xs_bind(struct rpc_xprt *xprt, struct socket *sock)
-{
-        struct sock *sk = sock->sk;
+        if (!xprt->inet) {
+                struct sock *sk = sock->sk;
 
-        if (xprt->inet)
-                return;
+                write_lock_bh(&sk->sk_callback_lock);
 
-        write_lock_bh(&sk->sk_callback_lock);
-        sk->sk_user_data = xprt;
-        xprt->old_data_ready = sk->sk_data_ready;
-        xprt->old_state_change = sk->sk_state_change;
-        xprt->old_write_space = sk->sk_write_space;
-        if (xprt->prot == IPPROTO_UDP) {
+                sk->sk_user_data = xprt;
+                xprt->old_data_ready = sk->sk_data_ready;
+                xprt->old_state_change = sk->sk_state_change;
+                xprt->old_write_space = sk->sk_write_space;
                 sk->sk_data_ready = xs_udp_data_ready;
                 sk->sk_write_space = xs_udp_write_space;
                 sk->sk_no_check = UDP_CSUM_NORCV;
+
                 xprt_set_connected(xprt);
-        } else {
-                tcp_sk(sk)->nonagle = 1;        /* disable Nagle's algorithm */
-                sk->sk_data_ready = xs_tcp_data_ready;
-                sk->sk_state_change = xs_tcp_state_change;
-                sk->sk_write_space = xs_tcp_write_space;
-                xprt_clear_connected(xprt);
-        }
 
-        /* Reset to new socket */
-        xprt->sock = sock;
-        xprt->inet = sk;
-        write_unlock_bh(&sk->sk_callback_lock);
+                /* Reset to new socket */
+                xprt->sock = sock;
+                xprt->inet = sk;
 
-        return;
+                write_unlock_bh(&sk->sk_callback_lock);
+        }
+        xs_set_buffer_size(xprt);
+        status = 0;
+out:
+        xprt_wake_pending_tasks(xprt, status);
+        xprt_clear_connecting(xprt);
 }
 
 /**
- * xs_connect_worker - try to connect a socket to a remote endpoint
+ * xs_tcp_connect_worker - connect a TCP socket to a remote endpoint
  * @args: RPC transport to connect
  *
  * Invoked by a work queue tasklet.
  */
-static void xs_connect_worker(void *args)
+static void xs_tcp_connect_worker(void *args)
 {
         struct rpc_xprt *xprt = (struct rpc_xprt *)args;
         struct socket *sock = xprt->sock;
-        int status = -EIO;
+        int err, status = -EIO;
 
         if (xprt->shutdown || xprt->addr.sin_port == 0)
                 goto out;
 
-        dprintk("RPC:      xs_connect_worker xprt %p\n", xprt);
+        dprintk("RPC:      xs_tcp_connect_worker for xprt %p\n", xprt);
 
-        /*
-         * Start by resetting any existing state
-         */
+        /* Start by resetting any existing socket state */
         xs_close(xprt);
-        sock = xs_create(xprt, xprt->prot, xprt->resvport);
-        if (sock == NULL) {
-                /* couldn't create socket or bind to reserved port;
-                 * this is likely a permanent error, so cause an abort */
+
+        if ((err = sock_create_kern(PF_INET, SOCK_STREAM, IPPROTO_TCP, &sock)) < 0) {
+                dprintk("RPC:      can't create TCP transport socket (%d).\n", -err);
                 goto out;
         }
-        xs_bind(xprt, sock);
-        xs_set_buffer_size(xprt);
 
-        status = 0;
-        if (!xprt->stream)
+        if (xprt->resvport && xs_bindresvport(xprt, sock) < 0) {
+                sock_release(sock);
                 goto out;
+        }
 
-        /*
-         * Tell the socket layer to start connecting...
-         */
+        if (!xprt->inet) {
+                struct sock *sk = sock->sk;
+
+                write_lock_bh(&sk->sk_callback_lock);
+
+                sk->sk_user_data = xprt;
+                xprt->old_data_ready = sk->sk_data_ready;
+                xprt->old_state_change = sk->sk_state_change;
+                xprt->old_write_space = sk->sk_write_space;
+                sk->sk_data_ready = xs_tcp_data_ready;
+                sk->sk_state_change = xs_tcp_state_change;
+                sk->sk_write_space = xs_tcp_write_space;
+                tcp_sk(sk)->nonagle = 1;
+
+                xprt_clear_connected(xprt);
+
+                /* Reset to new socket */
+                xprt->sock = sock;
+                xprt->inet = sk;
+
+                write_unlock_bh(&sk->sk_callback_lock);
+        }
+
+        /* Tell the socket layer to start connecting... */
         status = sock->ops->connect(sock, (struct sockaddr *) &xprt->addr,
                         sizeof(xprt->addr), O_NONBLOCK);
         dprintk("RPC: %p  connect status %d connected %d sock state %d\n",
@@ -959,18 +975,20 @@ static void xs_connect(struct rpc_task *task)
 {
         struct rpc_xprt *xprt = task->tk_xprt;
 
-        if (!xprt_test_and_set_connecting(xprt)) {
-                if (xprt->sock != NULL) {
-                        dprintk("RPC:      xs_connect delayed xprt %p\n", xprt);
-                        schedule_delayed_work(&xprt->connect_worker,
+        if (xprt_test_and_set_connecting(xprt))
+                return;
+
+        if (xprt->sock != NULL) {
+                dprintk("RPC:      xs_connect delayed xprt %p\n", xprt);
+                schedule_delayed_work(&xprt->connect_worker,
                                         RPC_REESTABLISH_TIMEOUT);
-                } else {
-                        dprintk("RPC:      xs_connect scheduled xprt %p\n", xprt);
-                        schedule_work(&xprt->connect_worker);
-                        /* flush_scheduled_work can sleep... */
-                        if (!RPC_IS_ASYNC(task))
-                                flush_scheduled_work();
-                }
+        } else {
+                dprintk("RPC:      xs_connect scheduled xprt %p\n", xprt);
+                schedule_work(&xprt->connect_worker);
+
+                /* flush_scheduled_work can sleep... */
+                if (!RPC_IS_ASYNC(task))
+                        flush_scheduled_work();
         }
 }
 
@@ -1013,7 +1031,7 @@ int xs_setup_udp(struct rpc_xprt *xprt, struct rpc_timeout *to)
         /* XXX: header size can vary due to auth type, IPv6, etc. */
         xprt->max_payload = (1U << 16) - (MAX_HEADER << 3);
 
-        INIT_WORK(&xprt->connect_worker, xs_connect_worker, xprt);
+        INIT_WORK(&xprt->connect_worker, xs_udp_connect_worker, xprt);
 
         xprt->ops = &xs_ops;
 
@@ -1052,7 +1070,7 @@ int xs_setup_tcp(struct rpc_xprt *xprt, struct rpc_timeout *to)
         xprt->resvport = capable(CAP_NET_BIND_SERVICE) ? 1 : 0;
         xprt->max_payload = (1U << 31) - 1;
 
-        INIT_WORK(&xprt->connect_worker, xs_connect_worker, xprt);
+        INIT_WORK(&xprt->connect_worker, xs_tcp_connect_worker, xprt);
 
         xprt->ops = &xs_ops;