[NET]: Avoid atomic xchg() for non-error case

It also looks like there were 2 places where the test on sk_err was
missing from the event wait logic (in sk_stream_wait_connect and
sk_stream_wait_memory), while the rest of the sock_error() users look
to be doing the right thing.  This version of the patch fixes those,
and cleans up a few places that were testing ->sk_err directly.

Signed-off-by: Benjamin LaHaise <benjamin.c.lahaise@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

7 files changed, 24 insertions, 16 deletions

diff --git a/include/net/sock.h b/include/net/sock.h
index 982b4ecd187b..0fbae85c6d55 100644
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -1166,7 +1166,10 @@ static inline int sock_queue_err_skb(struct sock *sk, struct sk_buff *skb)
  
 static inline int sock_error(struct sock *sk)
 {
-        int err = xchg(&sk->sk_err, 0);
+        int err;
+        if (likely(!sk->sk_err))
+                return 0;
+        err = xchg(&sk->sk_err, 0);
         return -err;
 }
 
diff --git a/net/bluetooth/af_bluetooth.c b/net/bluetooth/af_bluetooth.c
index ea616e3fc98e..fb031fe9be9e 100644
--- a/net/bluetooth/af_bluetooth.c
+++ b/net/bluetooth/af_bluetooth.c
@@ -287,10 +287,9 @@ int bt_sock_wait_state(struct sock *sk, int state, unsigned long timeo)
                 timeo = schedule_timeout(timeo);
                 lock_sock(sk);
 
-                if (sk->sk_err) {
-                        err = sock_error(sk);
+                err = sock_error(sk);
+                if (err)
                         break;
-                }
         }
         set_current_state(TASK_RUNNING);
         remove_wait_queue(sk->sk_sleep, &wait);
diff --git a/net/bluetooth/l2cap.c b/net/bluetooth/l2cap.c
index e3bb11ca4235..95f33cc7a24e 100644
--- a/net/bluetooth/l2cap.c
+++ b/net/bluetooth/l2cap.c
@@ -767,8 +767,9 @@ static int l2cap_sock_sendmsg(struct kiocb *iocb, struct socket *sock, struct ms
 
         BT_DBG("sock %p, sk %p", sock, sk);
 
-        if (sk->sk_err)
-                return sock_error(sk);
+        err = sock_error(sk);
+        if (err)
+                return err;
 
         if (msg->msg_flags & MSG_OOB)
                 return -EOPNOTSUPP;
diff --git a/net/bluetooth/sco.c b/net/bluetooth/sco.c
index 9cb00dc6c08c..648181430699 100644
--- a/net/bluetooth/sco.c
+++ b/net/bluetooth/sco.c
@@ -637,8 +637,9 @@ static int sco_sock_sendmsg(struct kiocb *iocb, struct socket *sock,
 
         BT_DBG("sock %p, sk %p", sock, sk);
 
-        if (sk->sk_err)
-                return sock_error(sk);
+        err = sock_error(sk);
+        if (err)
+                return err;
 
         if (msg->msg_flags & MSG_OOB)
                 return -EOPNOTSUPP;
diff --git a/net/core/stream.c b/net/core/stream.c
index 15bfd03e8024..35e25259fd95 100644
--- a/net/core/stream.c
+++ b/net/core/stream.c
@@ -55,8 +55,9 @@ int sk_stream_wait_connect(struct sock *sk, long *timeo_p)
         int done;
 
         do {
-                if (sk->sk_err)
-                        return sock_error(sk);
+                int err = sock_error(sk);
+                if (err)
+                        return err;
                 if ((1 << sk->sk_state) & ~(TCPF_SYN_SENT | TCPF_SYN_RECV))
                         return -EPIPE;
                 if (!*timeo_p)
@@ -67,6 +68,7 @@ int sk_stream_wait_connect(struct sock *sk, long *timeo_p)
                 prepare_to_wait(sk->sk_sleep, &wait, TASK_INTERRUPTIBLE);
                 sk->sk_write_pending++;
                 done = sk_wait_event(sk, timeo_p,
+                                     !sk->sk_err &&
                                      !((1 << sk->sk_state) & 
                                        ~(TCPF_ESTABLISHED | TCPF_CLOSE_WAIT)));
                 finish_wait(sk->sk_sleep, &wait);
@@ -137,7 +139,9 @@ int sk_stream_wait_memory(struct sock *sk, long *timeo_p)
 
                 set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
                 sk->sk_write_pending++;
-                sk_wait_event(sk, &current_timeo, sk_stream_memory_free(sk) &&
+                sk_wait_event(sk, &current_timeo, !sk->sk_err && 
+                                                  !(sk->sk_shutdown & SEND_SHUTDOWN) &&
+                                                  sk_stream_memory_free(sk) &&
                                                   vm_wait);
                 sk->sk_write_pending--;
 
diff --git a/net/irda/af_irda.c b/net/irda/af_irda.c
index 6f92f9c62990..f121f7de2032 100644
--- a/net/irda/af_irda.c
+++ b/net/irda/af_irda.c
@@ -1438,8 +1438,9 @@ static int irda_recvmsg_stream(struct kiocb *iocb, struct socket *sock,
                         /*
                          *      POSIX 1003.1g mandates this order.
                          */
-                        if (sk->sk_err)
-                                ret = sock_error(sk);
+                        ret = sock_error(sk);
+                        if (ret)
+                                break;
                         else if (sk->sk_shutdown & RCV_SHUTDOWN)
                                 ;
                         else if (noblock)
diff --git a/net/llc/af_llc.c b/net/llc/af_llc.c
index c3f0b0783453..b6d3df5c911c 100644
--- a/net/llc/af_llc.c
+++ b/net/llc/af_llc.c
@@ -566,10 +566,9 @@ static int llc_wait_data(struct sock *sk, long timeo)
                 /*
                  * POSIX 1003.1g mandates this order.
                  */
-                if (sk->sk_err) {
-                        rc = sock_error(sk);
+                rc = sock_error(sk);
+                if (rc)
                         break;
-                }
                 rc = 0;
                 if (sk->sk_shutdown & RCV_SHUTDOWN)
                         break;