Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S269063AbUIHPE1 (ORCPT ); Wed, 8 Sep 2004 11:04:27 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S267683AbUIHPCD (ORCPT ); Wed, 8 Sep 2004 11:02:03 -0400 Received: from cantor.suse.de ([195.135.220.2]:44461 "EHLO Cantor.suse.de") by vger.kernel.org with ESMTP id S269007AbUIHO6i (ORCPT ); Wed, 8 Sep 2004 10:58:38 -0400 Date: Wed, 8 Sep 2004 16:58:37 +0200 From: Andi Kleen To: "Michael S. Tsirkin" Cc: Andi Kleen , discuss@x86-64.org, linux-kernel@vger.kernel.org Subject: Re: [patch] Re: [discuss] f_ops flag to speed up compatible ioctls in linux kernel Message-ID: <20040908145837.GD15444@wotan.suse.de> References: <20040907142945.GB20981@wotan.suse.de> <20040907143702.GC1016@mellanox.co.il> <20040907144452.GC20981@wotan.suse.de> <20040907144543.GA1340@mellanox.co.il> <20040907151022.GA32287@wotan.suse.de> <20040907181641.GB2154@mellanox.co.il> <20040908065548.GE27886@wotan.suse.de> <20040908142808.GA11795@mellanox.co.il> <20040908143852.GA27411@wotan.suse.de> <20040908145432.GA12332@mellanox.co.il> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20040908145432.GA12332@mellanox.co.il> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1337 Lines: 39 > So I wander what goes on here- the syscall returns a long but > libc cuts the high 32 bit? System calls are always long, otherwise the syscall exit code cannot check properly for signal restarts. glibc seems to indeed truncate. > > Now that I think about it,for compat if you start returning 0 in low > 32 bits you are unlike to get the effect you wanted ... > The ioctl_native could be changed but that would make it impossible > for compatible ioctls to just use the same pointer in both. > > So what do you think - should I make just the native ioctl a long, > or both, and document that the high 32 bit are cut in the compat call? both + document. > > > The main thing missing is documentation. You need clear comments what > > the locking rules are and what compat is good for. > > Would these be best fit in the header file itself, or in a new > Documentation/ file? Header file should be enough. > > And you should change the code style to follow Documentation/CodingStyle > I'll go over it again. Something specific that I missed? e.g. your use of white space. -Andi - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/