net: Fix wrong interpretation of some copy_to_user() results.

I found some places, that erroneously return the value obtained from
the copy_to_user() call: if some amount of bytes were not able to get
to the user (this is what this one returns) the proper behavior is to
return the -EFAULT error, not that number itself.

Signed-off-by: Pavel Emelyanov <xemul@openvz.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/dccp/probe.c b/net/dccp/probe.c
index 6e1df62..0bcdc92 100644
--- a/net/dccp/probe.c
+++ b/net/dccp/probe.c
@@ -140,7 +140,7 @@
 		goto out_free;
 
 	cnt = kfifo_get(dccpw.fifo, tbuf, len);
-	error = copy_to_user(buf, tbuf, cnt);
+	error = copy_to_user(buf, tbuf, cnt) ? -EFAULT : 0;
 
 out_free:
 	vfree(tbuf);