From mboxrd@z Thu Jan 1 00:00:00 1970 Received: with ECARTIS (v1.0.0; list linux-mips); Tue, 06 Dec 2005 15:54:32 +0000 (GMT) Received: from fed1rmmtao09.cox.net ([68.230.241.30]:1429 "EHLO fed1rmmtao09.cox.net") by ftp.linux-mips.org with ESMTP id S8133511AbVLFPyM (ORCPT ); Tue, 6 Dec 2005 15:54:12 +0000 Received: from liberty.homelinux.org ([70.190.160.125]) by fed1rmmtao09.cox.net (InterMail vM.6.01.05.02 201-2131-123-102-20050715) with ESMTP id <20051206155349.FECG25099.fed1rmmtao09.cox.net@liberty.homelinux.org>; Tue, 6 Dec 2005 10:53:49 -0500 Received: (from mmporter@localhost) by liberty.homelinux.org (8.9.3/8.9.3/Debian 8.9.3-21) id IAA06907; Tue, 6 Dec 2005 08:53:47 -0700 Date: Tue, 6 Dec 2005 08:53:47 -0700 From: Matt Porter To: kernel coder Cc: linux-mips@linux-mips.org Subject: Re: zero copy Message-ID: <20051206085347.A32501@cox.net> References: Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.2.5i In-Reply-To: ; from lhrkernelcoder@gmail.com on Tue, Dec 06, 2005 at 04:06:06AM -0800 Return-Path: X-Envelope-To: <"|/home/ecartis/ecartis -s linux-mips"> (uid 0) X-Orcpt: rfc822;linux-mips@linux-mips.org Original-Recipient: rfc822;linux-mips@linux-mips.org X-archive-position: 9610 X-ecartis-version: Ecartis v1.0.0 Sender: linux-mips-bounce@linux-mips.org Errors-to: linux-mips-bounce@linux-mips.org X-original-sender: mporter@kernel.crashing.org Precedence: bulk X-list: linux-mips On Tue, Dec 06, 2005 at 04:06:06AM -0800, kernel coder wrote: > hi, > i'm trying to track the code flow of sendfile system call.Mine > ethernet card doesn't have scatter gather and checksum calculation > features.So stack should be making a copy of data. > > Please tell me where in sendfile code flow,check for scatter gather > and cecksum features is made so that stack can decide whether to copy > data from user space or not. Is your grep really that broken? :) net/ipv4/tcp.c:tcp_sendpage() is where you find the check and fallback to sendmsg if you follow it through. -Matt