[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>
diff --git a/net/bluetooth/af_bluetooth.c b/net/bluetooth/af_bluetooth.c
index ea616e3..fb031fe 100644
--- a/net/bluetooth/af_bluetooth.c
+++ b/net/bluetooth/af_bluetooth.c
@@ -287,10 +287,9 @@
 		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);