tipc: change sk_buffer handling in tipc_link_xmit()

When the function tipc_link_xmit() is given a buffer list for
transmission, it currently consumes the list both when transmission
is successful and when it fails, except for the special case when
it encounters link congestion.

This behavior is inconsistent, and needs to be corrected if we want
to avoid problems in later commits in this series.

In this commit, we change this to let the function consume the list
only when transmission is successful, and leave the list with the
sender in all other cases. We also modifiy the socket code so that
it adapts to this change, i.e., purges the list when a non-congestion
error code is returned.

Reviewed-by: Ying Xue <ying.xue@windriver.com>
Signed-off-by: Jon Maloy <jon.maloy@ericsson.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 26 insertions, 23 deletions

diff --git a/net/tipc/socket.c b/net/tipc/socket.c
index 3a7567f690f3..87fef25f6519 100644
--- a/net/tipc/socket.c
+++ b/net/tipc/socket.c
@@ -686,21 +686,22 @@ new_mtu:
 
         do {
                 rc = tipc_bclink_xmit(net, pktchain);
-                if (likely(rc >= 0)) {
-                        rc = dsz;
-                        break;
+                if (likely(!rc))
+                        return dsz;
+
+                if (rc == -ELINKCONG) {
+                        tsk->link_cong = 1;
+                        rc = tipc_wait_for_sndmsg(sock, &timeo);
+                        if (!rc)
+                                continue;
                 }
+                __skb_queue_purge(pktchain);
                 if (rc == -EMSGSIZE) {
                         msg->msg_iter = save;
                         goto new_mtu;
                 }
-                if (rc != -ELINKCONG)
-                        break;
-                tipc_sk(sk)->link_cong = 1;
-                rc = tipc_wait_for_sndmsg(sock, &timeo);
-                if (rc)
-                        __skb_queue_purge(pktchain);
-        } while (!rc);
+                break;
+        } while (1);
         return rc;
 }
 
@@ -925,23 +926,24 @@ new_mtu:
                 skb = skb_peek(pktchain);
                 TIPC_SKB_CB(skb)->wakeup_pending = tsk->link_cong;
                 rc = tipc_link_xmit(net, pktchain, dnode, tsk->portid);
-                if (likely(rc >= 0)) {
+                if (likely(!rc)) {
                         if (sock->state != SS_READY)
                                 sock->state = SS_CONNECTING;
-                        rc = dsz;
-                        break;
+                        return dsz;
                 }
+                if (rc == -ELINKCONG) {
+                        tsk->link_cong = 1;
+                        rc = tipc_wait_for_sndmsg(sock, &timeo);
+                        if (!rc)
+                                continue;
+                }
+                __skb_queue_purge(pktchain);
                 if (rc == -EMSGSIZE) {
                         m->msg_iter = save;
                         goto new_mtu;
                 }
-                if (rc != -ELINKCONG)
-                        break;
-                tsk->link_cong = 1;
-                rc = tipc_wait_for_sndmsg(sock, &timeo);
-                if (rc)
-                        __skb_queue_purge(pktchain);
-        } while (!rc);
+                break;
+        } while (1);
 
         return rc;
 }
@@ -1048,10 +1050,11 @@ next:
                                 tsk->sent_unacked++;
                                 sent += send;
                                 if (sent == dsz)
-                                        break;
+                                        return dsz;
                                 goto next;
                         }
                         if (rc == -EMSGSIZE) {
+                                __skb_queue_purge(pktchain);
                                 tsk->max_pkt = tipc_node_get_mtu(net, dnode,
                                                                  portid);
                                 m->msg_iter = save;
@@ -1059,13 +1062,13 @@ next:
                         }
                         if (rc != -ELINKCONG)
                                 break;
+
                         tsk->link_cong = 1;
                 }
                 rc = tipc_wait_for_sndpkt(sock, &timeo);
-                if (rc)
-                        __skb_queue_purge(pktchain);
         } while (!rc);
 
+        __skb_queue_purge(pktchain);
         return sent ? sent : rc;
 }