This is a note to let you know that I've just added the patch titled

    net: splice: avoid high order page splitting

to the 3.7-stable tree which can be found at:
    
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     net-splice-avoid-high-order-page-splitting.patch
and it can be found in the queue-3.7 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <[email protected]> know about it.


>From 6d0823b619aa6fc4280d61438626b7c6c9bb31ee Mon Sep 17 00:00:00 2001
From: Eric Dumazet <[email protected]>
Date: Sat, 5 Jan 2013 21:31:18 +0000
Subject: net: splice: avoid high order page splitting


From: Eric Dumazet <[email protected]>

[ Upstream commit 82bda6195615891181115f579a480aa5001ce7e9 ]

splice() can handle pages of any order, but network code tries hard to
split them in PAGE_SIZE units. Not quite successfully anyway, as
__splice_segment() assumed poff < PAGE_SIZE. This is true for
the skb->data part, not necessarily for the fragments.

This patch removes this logic to give the pages as they are in the skb.

Signed-off-by: Eric Dumazet <[email protected]>
Cc: Willy Tarreau <[email protected]>
Signed-off-by: David S. Miller <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
 net/core/skbuff.c |   38 +++++++++-----------------------------
 1 file changed, 9 insertions(+), 29 deletions(-)

--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -1677,20 +1677,6 @@ static bool spd_fill_page(struct splice_
        return false;
 }
 
-static inline void __segment_seek(struct page **page, unsigned int *poff,
-                                 unsigned int *plen, unsigned int off)
-{
-       unsigned long n;
-
-       *poff += off;
-       n = *poff / PAGE_SIZE;
-       if (n)
-               *page = nth_page(*page, n);
-
-       *poff = *poff % PAGE_SIZE;
-       *plen -= off;
-}
-
 static bool __splice_segment(struct page *page, unsigned int poff,
                             unsigned int plen, unsigned int *off,
                             unsigned int *len, struct sk_buff *skb,
@@ -1698,6 +1684,8 @@ static bool __splice_segment(struct page
                             struct sock *sk,
                             struct pipe_inode_info *pipe)
 {
+       unsigned int flen;
+
        if (!*len)
                return true;
 
@@ -1708,24 +1696,16 @@ static bool __splice_segment(struct page
        }
 
        /* ignore any bits we already processed */
-       if (*off) {
-               __segment_seek(&page, &poff, &plen, *off);
-               *off = 0;
-       }
-
-       do {
-               unsigned int flen = min(*len, plen);
+       poff += *off;
+       plen -= *off;
+       *off = 0;
 
-               /* the linear region may spread across several pages  */
-               flen = min_t(unsigned int, flen, PAGE_SIZE - poff);
+       flen = min(*len, plen);
 
-               if (spd_fill_page(spd, pipe, page, &flen, poff, skb, linear, 
sk))
-                       return true;
-
-               __segment_seek(&page, &poff, &plen, flen);
-               *len -= flen;
+       if (spd_fill_page(spd, pipe, page, &flen, poff, skb, linear, sk))
+               return true;
 
-       } while (*len && plen);
+       *len -= flen;
 
        return false;
 }


Patches currently in stable-queue which might be from [email protected] are

queue-3.7/tcp-frto-should-not-set-snd_cwnd-to-0.patch
queue-3.7/net-splice-avoid-high-order-page-splitting.patch
queue-3.7/ipv6-ip6_gre-fix-error-case-handling-in-ip6gre_tunnel_xmit.patch
queue-3.7/tcp-fix-a-panic-on-up-machines-in-reqsk_fastopen_remove.patch
queue-3.7/ip_gre-fix-kernel-panic-in-ip_gre-with-gre-csum.patch
queue-3.7/tcp-fix-for-zero-packets_in_flight-was-too-broad.patch
queue-3.7/tcp-fix-splice-and-tcp-collapsing-interaction.patch
queue-3.7/net-prevent-setting-ttl-0-via-ip_ttl.patch
queue-3.7/tcp-don-t-abort-splice-after-small-transfers.patch
queue-3.7/macvlan-fix-macvlan_get_size.patch
queue-3.7/net-splice-fix-__splice_segment.patch
queue-3.7/net-wireless-overwrite-default_ethtool_ops.patch
queue-3.7/netxen-fix-off-by-one-bug-in-netxen_release_tx_buffer.patch
queue-3.7/net-loopback-fix-a-dst-refcounting-issue.patch
queue-3.7/tcp-fix-incorrect-lockdroppedicmps-counter.patch
queue-3.7/tcp-splice-fix-an-infinite-loop-in-tcp_read_sock.patch
queue-3.7/tcp-fix-an-infinite-loop-in-tcp_slow_start.patch
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