From: Randy Dunlap Subject: Re: Interface for the new fallocate() system call Date: Thu, 5 Apr 2007 08:50:16 -0700 Message-ID: <20070405085016.a513526b.randy.dunlap@oracle.com> References: <20070117094658.GA17390@amitarora.in.ibm.com> <20070225022326.137b4875.akpm@linux-foundation.org> <20070301183445.GA7911@amitarora.in.ibm.com> <20070316143101.GA10152@amitarora.in.ibm.com> <20070316161704.GE8525@osiris.boeblingen.de.ibm.com> <20070317111036.GC29931@parisc-linux.org> <20070321120425.GA27273@amitarora.in.ibm.com> <20070329115126.GB7374@amitarora.in.ibm.com> <20070329101010.7a2b8783.akpm@linux-foundation.org> <20070330071417.GI355@devserv.devel.redhat.com> <20070405112619.GA19982@amitarora.in.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Cc: Jakub Jelinek , Andrew Morton , torvalds@linux-foundation.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, linux-ext4@vger.kernel.org, xfs@oss.sgi.com, suparna@in.ibm.com, cmm@us.ibm.com To: "Amit K. Arora" Return-path: In-Reply-To: <20070405112619.GA19982@amitarora.in.ibm.com> Sender: linux-fsdevel-owner@vger.kernel.org List-Id: linux-ext4.vger.kernel.org On Thu, 5 Apr 2007 16:56:19 +0530 Amit K. Arora wrote: > On Fri, Mar 30, 2007 at 02:14:17AM -0500, Jakub Jelinek wrote: > > Wouldn't > > int fallocate(loff_t offset, loff_t len, int fd, int mode) > > work on both s390 and ppc/arm? glibc will certainly wrap it and > > reorder the arguments as needed, so there is no need to keep fd first. > > This should work on all the platforms. The only concern I can think of > here is the convention being followed till now, where all the entities on > which the action has to be performed by the kernel (say fd, file/device > name, pid etc.) is the first argument of the system call. If we can live > with the small exception here, fine. > > Or else, we may have to implement the > > int fd, int mode, loff_t offset, loff_t len > > as the layout of arguments here. I think only s390 will have a problem > with this, and we can think of a workaround for it (may be similar to > what ARM did to implement sync_file_range() system call) : > > asmlinkage long sys_s390_fallocate(int fd, loff_t offset, loff_t len, int mode) > { > return sys_fallocate(fd, offset, len, mode); > } > > > To me both the approaches look slightly unconventional. But, we need to > compromise somewhere to make things work on all the platforms. > > Any thoughts on which one of the above should we finalize on ? > > Thanks! If s390 can work around the calling order that easily, I certainly prefer the more conventional ordering of: > int fd, int mode, loff_t offset, loff_t len --- ~Randy *** Remember to use Documentation/SubmitChecklist when testing your code ***