Correct the connection logic for TCP. Now we have not only a cleaner

connection, but a more thread safe one. Thanks to Pierre for his
help on this.

This commit was SVN r17853.

ompi/mca/btl/tcp/btl_tcp_endpoint.c

@@ -204,7 +204,7 @@ static void mca_btl_tcp_endpoint_dump(mca_btl_base_endpoint_t* btl_endpoint, con
  * Initialize events to be used by the endpoint instance for TCP select/poll callbacks.
  */
 
-static inline void mca_btl_tcp_endpoint_event_init(mca_btl_base_endpoint_t* btl_endpoint, int sd)
+static inline void mca_btl_tcp_endpoint_event_init(mca_btl_base_endpoint_t* btl_endpoint)
 {
 #if MCA_BTL_TCP_ENDPOINT_CACHE
     btl_endpoint->endpoint_cache     = (char*)malloc(mca_btl_tcp_component.tcp_endpoint_cache);
@@ -216,9 +216,15 @@ static inline void mca_btl_tcp_endpoint_event_init(mca_btl_base_endpoint_t* btl_
                     OPAL_EV_READ|OPAL_EV_PERSIST, 
                     mca_btl_tcp_endpoint_recv_handler,
                     btl_endpoint );
+    /**
+     * The send event should be non persistent until the endpoint is
+     * completely connected. This means, when the event is created it
+     * will be fired only once, and when the endpoint is marked as 
+     * CONNECTED the event should be recreated with the correct flags.
+     */
     opal_event_set( &btl_endpoint->endpoint_send_event, 
                     btl_endpoint->endpoint_sd, 
-                   OPAL_EV_WRITE|OPAL_EV_PERSIST, 
+                    OPAL_EV_WRITE, 
                     mca_btl_tcp_endpoint_send_handler,
                     btl_endpoint);
 }
@@ -265,9 +271,6 @@ int mca_btl_tcp_endpoint_send(mca_btl_base_endpoint_t* btl_endpoint, mca_btl_tcp
             opal_list_append(&btl_endpoint->endpoint_frags, (opal_list_item_t*)frag);
         }
         break;
-    case MCA_BTL_TCP_SHUTDOWN:
-        rc = OMPI_ERROR;
-        break;
     }
     OPAL_THREAD_UNLOCK(&btl_endpoint->endpoint_send_lock);
     return rc;
@@ -358,7 +361,7 @@ bool mca_btl_tcp_endpoint_accept(mca_btl_base_endpoint_t* btl_endpoint,
             OPAL_THREAD_UNLOCK(&btl_endpoint->endpoint_recv_lock);
             return false;
         }
-        mca_btl_tcp_endpoint_event_init(btl_endpoint, sd);
+        mca_btl_tcp_endpoint_event_init(btl_endpoint);
         opal_event_add(&btl_endpoint->endpoint_recv_event, 0);
         mca_btl_tcp_endpoint_connected(btl_endpoint);
 #if OMPI_ENABLE_DEBUG && WANT_PEER_DUMP
@@ -381,7 +384,10 @@ bool mca_btl_tcp_endpoint_accept(mca_btl_base_endpoint_t* btl_endpoint,
  */
 void mca_btl_tcp_endpoint_close(mca_btl_base_endpoint_t* btl_endpoint)
 {
-    if(btl_endpoint->endpoint_sd >= 0) {
+    if(btl_endpoint->endpoint_sd < 0)
+        return;
+    btl_endpoint->endpoint_state = MCA_BTL_TCP_CLOSED;
+    btl_endpoint->endpoint_retries++;
     opal_event_del(&btl_endpoint->endpoint_recv_event);
     opal_event_del(&btl_endpoint->endpoint_send_event);
     CLOSE_THE_SOCKET(btl_endpoint->endpoint_sd);
@@ -393,24 +399,11 @@ void mca_btl_tcp_endpoint_close(mca_btl_base_endpoint_t* btl_endpoint)
     btl_endpoint->endpoint_cache_length = 0;
 #endif  /* MCA_BTL_TCP_ENDPOINT_CACHE */
 }
-    btl_endpoint->endpoint_state = MCA_BTL_TCP_CLOSED;
-    btl_endpoint->endpoint_retries++;
-}
-
-void mca_btl_tcp_endpoint_shutdown(mca_btl_base_endpoint_t* btl_endpoint)
-{
-    OPAL_THREAD_LOCK(&btl_endpoint->endpoint_recv_lock);
-    OPAL_THREAD_LOCK(&btl_endpoint->endpoint_send_lock);
-    mca_btl_tcp_endpoint_close(btl_endpoint);
-    btl_endpoint->endpoint_state = MCA_BTL_TCP_SHUTDOWN;
-    OPAL_THREAD_UNLOCK(&btl_endpoint->endpoint_send_lock);
-    OPAL_THREAD_UNLOCK(&btl_endpoint->endpoint_recv_lock);
-}
-
 
 /*
  *  Setup endpoint state to reflect that connection has been established,
- *  and start any pending sends.
+ *  and start any pending sends. This function should be called with the
+ *  send lock locked.
  */
 
 static void mca_btl_tcp_endpoint_connected(mca_btl_base_endpoint_t* btl_endpoint)
@@ -418,6 +411,14 @@ static void mca_btl_tcp_endpoint_connected(mca_btl_base_endpoint_t* btl_endpoint
     /* setup socket options */
     btl_endpoint->endpoint_state = MCA_BTL_TCP_CONNECTED;
     btl_endpoint->endpoint_retries = 0;
+
+    /* Create the send event in a persistent manner. */
+    opal_event_set( &btl_endpoint->endpoint_send_event, 
+                   btl_endpoint->endpoint_sd, 
+                   OPAL_EV_WRITE | OPAL_EV_PERSIST,
+                   mca_btl_tcp_endpoint_send_handler,
+                   btl_endpoint);
+
     if(opal_list_get_size(&btl_endpoint->endpoint_frags) > 0) {
         if(NULL == btl_endpoint->endpoint_send_frag)
             btl_endpoint->endpoint_send_frag = (mca_btl_tcp_frag_t*)
@@ -447,8 +448,8 @@ static int mca_btl_tcp_endpoint_recv_blocking(mca_btl_base_endpoint_t* btl_endpo
         /* socket is non-blocking so handle errors */
         if(retval < 0) {
             if(opal_socket_errno != EINTR && opal_socket_errno != EAGAIN && opal_socket_errno != EWOULDBLOCK) {
-                BTL_ERROR(("recv() failed: %s (%d)",
-                           strerror(opal_socket_errno), opal_socket_errno));
+                BTL_ERROR(("recv(%d) failed: %s (%d)",
+                           btl_endpoint->endpoint_sd, strerror(opal_socket_errno), opal_socket_errno));
                 mca_btl_tcp_endpoint_close(btl_endpoint);
                 return -1;
             }
@@ -482,9 +483,6 @@ static int mca_btl_tcp_endpoint_recv_connect_ack(mca_btl_base_endpoint_t* btl_en
         return OMPI_ERR_UNREACH;
     }
 
-#if OMPI_ENABLE_DEBUG && WANT_PEER_DUMP
-    mca_btl_tcp_endpoint_dump(btl_endpoint, "connected");
-#endif
     return OMPI_SUCCESS;
 }
 
@@ -549,7 +547,7 @@ static int mca_btl_tcp_endpoint_start_connect(mca_btl_base_endpoint_t* btl_endpo
     mca_btl_tcp_set_socket_options(btl_endpoint->endpoint_sd);
 
     /* setup event callbacks */
-    mca_btl_tcp_endpoint_event_init(btl_endpoint, btl_endpoint->endpoint_sd);
+    mca_btl_tcp_endpoint_event_init(btl_endpoint);
 
     /* setup the socket as non-blocking */
     if((flags = fcntl(btl_endpoint->endpoint_sd, F_GETFL, 0)) < 0) {
@@ -642,11 +640,13 @@ static void mca_btl_tcp_endpoint_recv_handler(int sd, short flags, void* user)
 {
     mca_btl_base_endpoint_t* btl_endpoint = (mca_btl_base_endpoint_t *)user;
 
+    if( sd != btl_endpoint->endpoint_sd )
+        return;
     OPAL_THREAD_LOCK(&btl_endpoint->endpoint_recv_lock);
     switch(btl_endpoint->endpoint_state) {
     case MCA_BTL_TCP_CONNECT_ACK:
         {
-            int rc;
+            int rc = OMPI_ERROR;
             rc = mca_btl_tcp_endpoint_recv_connect_ack(btl_endpoint);
             OPAL_THREAD_UNLOCK(&btl_endpoint->endpoint_recv_lock);
             if( OMPI_SUCCESS == rc ) {
@@ -654,6 +654,9 @@ static void mca_btl_tcp_endpoint_recv_handler(int sd, short flags, void* user)
                 OPAL_THREAD_LOCK(&btl_endpoint->endpoint_send_lock);
                 mca_btl_tcp_endpoint_connected(btl_endpoint);
                 OPAL_THREAD_UNLOCK(&btl_endpoint->endpoint_send_lock);
+#if OMPI_ENABLE_DEBUG && WANT_PEER_DUMP
+                mca_btl_tcp_endpoint_dump(btl_endpoint, "connected");
+#endif
             }
             break;
         }
@@ -683,7 +686,7 @@ static void mca_btl_tcp_endpoint_recv_handler(int sd, short flags, void* user)
         data_still_pending_on_endpoint:
 #endif  /* MCA_BTL_TCP_ENDPOINT_CACHE */
             /* check for completion of non-blocking recv on the current fragment */
-            if(mca_btl_tcp_frag_recv(frag, sd) == false) {
+            if(mca_btl_tcp_frag_recv(frag, btl_endpoint->endpoint_sd) == false) {
                 btl_endpoint->endpoint_recv_frag = frag;
             } else {
                 btl_endpoint->endpoint_recv_frag = NULL;
@@ -709,7 +712,13 @@ static void mca_btl_tcp_endpoint_recv_handler(int sd, short flags, void* user)
             OPAL_THREAD_UNLOCK(&btl_endpoint->endpoint_recv_lock);
             break;
         }
-    case MCA_BTL_TCP_SHUTDOWN:
+    case MCA_BTL_TCP_CLOSED:
+        /* This is a thread-safety issue. As multiple threads are allowed
+         * to generate events (in the lib event) we endup with several
+         * threads executing the receive callback, when we reach the end
+         * of the MPI_Finalize. The first one will close the connections,
+         * and all others will complain.
+         */
         OPAL_THREAD_UNLOCK(&btl_endpoint->endpoint_recv_lock);
         break;
     default:

ompi/mca/btl/tcp/btl_tcp_endpoint.h

@@ -40,8 +40,7 @@ typedef enum {
     MCA_BTL_TCP_CONNECT_ACK,
     MCA_BTL_TCP_CLOSED,
     MCA_BTL_TCP_FAILED,
-    MCA_BTL_TCP_CONNECTED,
-    MCA_BTL_TCP_SHUTDOWN
+    MCA_BTL_TCP_CONNECTED
 } mca_btl_tcp_state_t;
 
 /**