[Devel] [PATCH RHEL7 COMMIT] ms/af_unix: fix bug on large send()

[Konstantin Khorenko]

The commit is pushed to "branch-rh7-3.10.0-123.1.2-ovz" and will appear at https://src.openvz.org/scm/ovz/vzkernel.git
after rh7-3.10.0-123.1.2.vz7.5.17
------>
commit da976ea2c2d9cd9084c60ba87ca4fde237ccb5c1
Author: Kirill Tkhai <ktkhai at odin.com>
Date:   Wed Jun 24 17:49:58 2015 +0400

    ms/af_unix: fix bug on large send()
    
    Port commit f3dfd20860db3d0c400dd83a378176a28d3662db from mainstream.
    
    commit e370a723632 ("af_unix: improve STREAM behavior with fragmented
    memory") added a bug on large send() because the
    skb_copy_datagram_from_iovec() call always start from the beginning
    of iovec.
    
    We must instead use the @sent variable to properly skip the
    already processed part.
    
    Reported-by: Hannes Frederic Sowa <hannes at stressinduktion.org>
    Signed-off-by: Eric Dumazet <edumazet at google.com>
    Signed-off-by: David S. Miller <davem at davemloft.net>
    Signed-off-by: Kirill Tkhai <ktkhai at odin.com>
---
 net/unix/af_unix.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/net/unix/af_unix.c b/net/unix/af_unix.c
index 601f4cb..01625cc 100644
--- a/net/unix/af_unix.c
+++ b/net/unix/af_unix.c
@@ -1679,7 +1679,8 @@ static int unix_stream_sendmsg(struct kiocb *kiocb, struct socket *sock,
 		skb_put(skb, size - data_len);
 		skb->data_len = data_len;
 		skb->len = size;
-		err = skb_copy_datagram_from_iovec(skb, 0, msg->msg_iov, 0, size);
+		err = skb_copy_datagram_from_iovec(skb, 0, msg->msg_iov,
+						   sent, size);
 		if (err) {
 			kfree_skb(skb);
 			goto out_err;