From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from canuck.infradead.org ([209.217.80.40]:57028 "EHLO canuck.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752776AbXFYNeh (ORCPT ); Mon, 25 Jun 2007 09:34:37 -0400 Subject: Re: Introduce fixed sys_sync_file_range2() syscall, implement on PowerPC and ARM From: David Woodhouse In-Reply-To: <44a862a6e0b8df8765958d456d9b17d6@kernel.crashing.org> References: <1182761357.12109.14.camel@pmac.infradead.org> <20070625021145.b84ea186.akpm@linux-foundation.org> <20070625103535.GF22063@parisc-linux.org> <20070625110907.GA23438@flint.arm.linux.org.uk> <1182771454.12109.71.camel@pmac.infradead.org> <20070625114742.GG22063@parisc-linux.org> <2fc3aacccf036072f1b959e7b9ec3629@kernel.crashing.org> <1182774873.12109.83.camel@pmac.infradead.org> <44a862a6e0b8df8765958d456d9b17d6@kernel.crashing.org> Content-Type: text/plain Date: Mon, 25 Jun 2007 14:33:46 +0100 Message-Id: <1182778426.12109.87.camel@pmac.infradead.org> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-arch-owner@vger.kernel.org To: Segher Boessenkool Cc: torvalds@linux-foundation.org, Russell King , Matthew Wilcox , Andrew Morton , drepper@redhat.com, paulus@samba.org, linux-arch@vger.kernel.org List-ID: On Mon, 2007-06-25 at 15:10 +0200, Segher Boessenkool wrote: > >> I don't see any 64-bit integers here. > > > > Of course not. This is the routine which is called from 32-bit code. > > The prototype in the 32-bit code is (int, unsigned, loff_t, loff_t). > > Ah I see, sorry for the confusion. > Yes exactly, signed integers need sign extensions, which > makes them less efficient. Some ABIs need zero extensions > too, but on a whole unsigned works better. Most of the > time you don't need to do much on the (C code) kernel side > of things. Most of the time, true. But not in the case we're actually talking about. > Is this enough handwaving? I'm sure someone else can explain > this a lot better than me :-) Perhaps so :) -- dwmw2