From mboxrd@z Thu Jan 1 00:00:00 1970 From: Arnd Bergmann Subject: Re: [PATCH 1/3] X86_64: Optimise fls(), ffs() and fls64() Date: Fri, 16 Dec 2011 13:57:14 +0000 Message-ID: <201112161357.14463.arnd@arndb.de> References: <20111213145654.14362.39868.stgit@warthog.procyon.org.uk> <5476903.m0O6cTqH9B@wuerfel> <4EEA89B6.7030204@zytor.com> Mime-Version: 1.0 Content-Type: Text/Plain; charset="utf-8" Content-Transfer-Encoding: 7bit Return-path: Received: from moutng.kundenserver.de ([212.227.126.171]:49241 "EHLO moutng.kundenserver.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751953Ab1LPN5m (ORCPT ); Fri, 16 Dec 2011 08:57:42 -0500 In-Reply-To: <4EEA89B6.7030204@zytor.com> Sender: linux-arch-owner@vger.kernel.org List-ID: To: "H. Peter Anvin" Cc: David Howells , tglx@linutronix.de, mingo@redhat.com, x86@kernel.org, linux-arch@vger.kernel.org On Thursday 15 December 2011, H. Peter Anvin wrote: > On 12/15/2011 02:43 PM, Arnd Bergmann wrote: > > On Thursday 15 December 2011 13:29:07 H. Peter Anvin wrote: > >> On 12/13/2011 06:56 AM, David Howells wrote: > >>> > >>> +#if BITS_PER_LONG == 32 > >>> #include > >>> +#endif > >>> > >> > >> This is outside __KERNEL__, and thus ends up changing what is exported > >> to userspace (specifically, fls64.h won't be included for 64-bit > >> non-__KERNEL__ anymore.) Is this a bug? > > > > Not sure, but I think it's a bug to use BITS_PER_LONG rather than > > __BITS_PER_LONG outside of __KERNEL__. > > > > Yes, it's one of many issues with this stuff. After tracking down > things a bit further it looks like this was simply a conversion error in > checkin: > > d57594c203b1 bitops: use __fls for fls64 on 64-bit archs Hmm, I also looked a bit closer and noticed that we don't actually export any bitops headers to user space, so any use of __KERNEL__ in those headers is bogus, but I don't think there is an actual bug here. Arnd