[PATCH][ATM]: better behavior for sendmsg/recvmsg during async closes

[chas williams (contractor) <chas@xxxxxxxxxxxxxxxx>]

sendmsg() should probably just return -EPIPE (and send SIGPIPE) instead
of returning the error from sigd during an asynchronus close. often 
the error code is 0 when the other side cleanly terminates the svc 
since its likely the other side closed the svc without a 'hard' error.

recvmsg() shouldnt return EPIPE (this isnt a 'valid' return code for
recvmsg).  returning 0 (end of file) seems the best idea when the remote
side has closed first.

please apply to 2.4

# This is a BitKeeper generated patch for the following project:
# Project Name: Linux kernel tree
# This patch format is intended for GNU patch command version 2.5 or higher.
# This patch includes the following deltas:
#                  ChangeSet    1.1168  -> 1.1169 
#           net/atm/common.c    1.36    -> 1.37   
#
# The following is the BitKeeper ChangeSet Log
# --------------------------------------------
# 04/01/14      chas@xxxxxxxxxxxxxxxxxxxxxx     1.1169
# [ATM]: better behavior for sendmsg/recvmsg during async closes
# --------------------------------------------
#
diff -Nru a/net/atm/common.c b/net/atm/common.c
--- a/net/atm/common.c  Wed Jan 14 22:13:22 2004
+++ b/net/atm/common.c  Wed Jan 14 22:13:22 2004
@@ -629,11 +629,10 @@
        if (flags & ~MSG_DONTWAIT)              /* only handle MSG_DONTWAIT */
                return -EOPNOTSUPP;
        vcc = ATM_SD(sock);
-       if (test_bit(ATM_VF_RELEASED,&vcc->flags) ||
-           test_bit(ATM_VF_CLOSE,&vcc->flags))
-               return -sk->err;
-       if (!test_bit(ATM_VF_READY, &vcc->flags))
-               return 0;
+       if (test_bit(ATM_VF_RELEASED, &vcc->flags) ||
+           test_bit(ATM_VF_CLOSE, &vcc->flags) ||
+           !test_bit(ATM_VF_READY, &vcc->flags))
+               return 0;                       /* end of file */
  
        skb = skb_recv_datagram(sk, flags, flags & MSG_DONTWAIT, &error);
        if (!skb)
@@ -688,12 +687,10 @@
        size = m->msg_iov->iov_len;
        vcc = ATM_SD(sock);
        if (test_bit(ATM_VF_RELEASED, &vcc->flags) ||
-           test_bit(ATM_VF_CLOSE, &vcc->flags)) {
-               error = -sk->err;
-               goto out;
-       }
-       if (!test_bit(ATM_VF_READY, &vcc->flags)) {
-               error = -EPIPE;
+           test_bit(ATM_VF_CLOSE, &vcc->flags) ||
+           !test_bit(ATM_VF_READY, &vcc->flags)) {
+               error = -EPIPE;
+               send_sig(SIGPIPE, current, 0);
                goto out;
        }
        if (!size) {
@@ -721,12 +718,10 @@
                        break;
                }
                if (test_bit(ATM_VF_RELEASED,&vcc->flags) ||
-                   test_bit(ATM_VF_CLOSE,&vcc->flags)) {
-                       error = -sk->err;
-                       break;
-               }
-               if (!test_bit(ATM_VF_READY,&vcc->flags)) {
+                   test_bit(ATM_VF_CLOSE,&vcc->flags) ||
+                   !test_bit(ATM_VF_READY,&vcc->flags)) {
                        error = -EPIPE;
+                       send_sig(SIGPIPE, current, 0);
                        break;
                }
        }