From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755266Ab2GXUKw (ORCPT ); Tue, 24 Jul 2012 16:10:52 -0400 Received: from mx1.redhat.com ([209.132.183.28]:49934 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755018Ab2GXUKw (ORCPT ); Tue, 24 Jul 2012 16:10:52 -0400 Date: Tue, 24 Jul 2012 16:10:45 -0400 From: Josh Boyer To: Linus Torvalds Cc: Jeff Law , Andrew Morton , linux-kernel@vger.kernel.org Subject: Re: [PATCH v2] posix_types.h: make __NFDBITS compatible with glibc definition Message-ID: <20120724201045.GH10534@zod.bos.redhat.com> References: <20120724182409.GB10534@zod.bos.redhat.com> <20120724183230.GC10534@zod.bos.redhat.com> <20120724190302.GE10534@zod.bos.redhat.com> <500EF43C.3060200@redhat.com> <500EF6EF.4080708@redhat.com> <20120724194301.GG10534@zod.bos.redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Jul 24, 2012 at 12:55:38PM -0700, Linus Torvalds wrote: > On Tue, Jul 24, 2012 at 12:43 PM, Josh Boyer wrote: > >+ ({ long int __d = (d); \ > > (__builtin_constant_p (__d) \ > >- ? (__d >= __FD_SETSIZE \ > >- ? __fdelt_warn (__d) : (__d / __NFDBITS)) \ > >+ ? (0 <= __d && __d < __FD_SETSIZE \ > >+ ? (__d / __NFDBITS) \ > >+ : __fdelt_warn (__d)) \ > > : __fdelt_chk (__d)); }) > > Ugh. This depends intimately on gcc doing the whole value range > propagation thing, and probably generates horrible code when not > optimizing, but whatever. It's irrelevant. > > I vote we get rid of the crap. We'll force-redefine __FD_SETSIZE, > because that's the one we really care about. And then just use our > internal names for anything else. Your vote counts more than mine ;). I just want the problem solved in a reasonable fasion since it's causing build failures now and the bug was stalled. > IOW, just something like this (whitespace-damaged on purpose, because > it won't even compile as-is: we'll also need to replace the few uses > of __NFDBITS in the kernel with BITS_PER_LONG). > > diff --git a/include/linux/posix_types.h b/include/linux/posix_types.h > index f04c98cf44f3..8a79a5021dc1 100644 > --- a/include/linux/posix_types.h > +++ b/include/linux/posix_types.h > @@ -15,26 +15,14 @@ > */ > > /* > - * Those macros may have been defined in . But we always > - * use the ones here. > + * This macro may have been defined in . But we always > + * use the one here. > */ > -#undef __NFDBITS > -#define __NFDBITS (8 * sizeof(unsigned long)) > - > #undef __FD_SETSIZE > #define __FD_SETSIZE 1024 > > -#undef __FDSET_LONGS > -#define __FDSET_LONGS (__FD_SETSIZE/__NFDBITS) > - > -#undef __FDELT > -#define __FDELT(d) ((d) / __NFDBITS) > - > -#undef __FDMASK > -#define __FDMASK(d) (1UL << ((d) % __NFDBITS)) > - > typedef struct { > - unsigned long fds_bits [__FDSET_LONGS]; > + unsigned long fds_bits [__FD_SETSIZE / (8*sizeof(long))]; > } __kernel_fd_set; > > /* Type of a signal handler. */ > > Hmm? Seems fine to me. In addition to the s/__NFDBITS/BITS_PER_LONG change, I'm guessing you'll want the odd FD_ISSET/CLR/ZERO/etc macros in linux/time.h killed as well? If you don't get to it before me, I'll try whipping something up either later this evening or first thing in the morning. josh