From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751494Ab3ASGNU (ORCPT ); Sat, 19 Jan 2013 01:13:20 -0500 Received: from mail-pb0-f54.google.com ([209.85.160.54]:65516 "EHLO mail-pb0-f54.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751051Ab3ASGNS (ORCPT ); Sat, 19 Jan 2013 01:13:18 -0500 Subject: Re: splice() giving unexpected EOF in 3.7.3 and 3.8-rc4+ From: Eric Dumazet To: Eric Wong , David Miller Cc: linux-kernel@vger.kernel.org, netdev@vger.kernel.org, linux-fsdevel@vger.kernel.org, Willy Tarreau In-Reply-To: <1358574847.3464.422.camel@edumazet-glaptop> References: <20130119044957.GA25395@dcvr.yhbt.net> <1358574847.3464.422.camel@edumazet-glaptop> Content-Type: text/plain; charset="UTF-8" Date: Fri, 18 Jan 2013 22:13:16 -0800 Message-ID: <1358575996.3464.447.camel@edumazet-glaptop> Mime-Version: 1.0 X-Mailer: Evolution 2.28.3 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 2013-01-18 at 21:54 -0800, Eric Dumazet wrote: > > Hmm, this might be already fixed in net-next tree, could you try it ? > Yes, running your program on net-next seems OK. David, we need the two following commits. They actually fixed a bug : current code in Linus tree can push to the pipe a 0-length frag, because of the : flen = min_t(unsigned int, flen, PAGE_SIZE - poff); It can happen if poff == PAGE_SIZE, when one skb frag has this particular starting offset. commit 9ca1b22d6d228177e6f929f6818a1cd3d5e30c4a Author: Eric Dumazet Date: Sat Jan 5 21:31:18 2013 +0000 net: splice: avoid high order page splitting 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 Cc: Willy Tarreau Signed-off-by: David S. Miller commit 18aafc622abf492809723d9c5a3c5dcea287169e Author: Eric Dumazet Date: Fri Jan 11 14:46:37 2013 +0000 net: splice: fix __splice_segment() commit 9ca1b22d6d2 (net: splice: avoid high order page splitting) forgot that skb->head could need a copy into several page frags. This could be the case for loopback traffic mostly. Also remove now useless skb argument from linear_to_page() and __splice_segment() prototypes. Signed-off-by: Eric Dumazet Cc: Willy Tarreau Signed-off-by: David S. Miller