Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933334AbXJQPMU (ORCPT ); Wed, 17 Oct 2007 11:12:20 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1760569AbXJQPMG (ORCPT ); Wed, 17 Oct 2007 11:12:06 -0400 Received: from ms-smtp-01.nyroc.rr.com ([24.24.2.55]:53525 "EHLO ms-smtp-01.nyroc.rr.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756049AbXJQPMD (ORCPT ); Wed, 17 Oct 2007 11:12:03 -0400 Subject: Re: [RT] seqlocks: use of PICK_FUNCTION breaks kernel compile when CONFIG_GENERIC_TIME is NOT set From: Steven Rostedt To: Daniel Walker Cc: Remy Bohmer , Ingo Molnar , LKML , RT , Thomas Gleixner In-Reply-To: <1192632502.17527.129.camel@imap.mvista.com> References: <1192632502.17527.129.camel@imap.mvista.com> Content-Type: text/plain Date: Wed, 17 Oct 2007 11:10:35 -0400 Message-Id: <1192633836.8265.6.camel@localhost.localdomain> Mime-Version: 1.0 X-Mailer: Evolution 2.10.3 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2745 Lines: 83 On Wed, 2007-10-17 at 07:48 -0700, Daniel Walker wrote: > Steven, > > Could you include this patch, it was submitted on the list but you > didn't get CC'd .. Thanks, it may have been a while before I see this (/me has been nose deep in debugging). > > On Tue, 2007-10-16 at 10:35 +0200, Remy Bohmer wrote: > > > Hello Daniel and Ingo, > > > > > > I use 2.6.23-rt1 and the patch of Daniel below which seems to be in > > > there breaks the compilation of the RT-kernel when CONFIG_GENERIC_TIME > > > is NOT set. > > > > > > It breaks in the do_gettimeofday(struct timeval *tv) code in the > > > architecture specific code > > > where there is a call to: seq = read_seqbegin_irqsave(&xtime_lock, flags); > > > The PICK_FUNCTION implementation does not return anything, so the > > > compile breaks here. > > > > > > I am figuring out how to solve this problem nicely, but I have not > > > found a nice solution yet. Attached I have put my hack to make it > > > compile on ARM again, but maybe one of you can do a better proposal to > > > fix this. > > > > Here's another fix for this. I compile tested for ARM (!GENERIC_TIME) , > > but I didn't boot test .. Could you boot test this patch? > > > > --- > > > > Move the read_seqbegin() call up in the chain so the value > > can be returned > > > > Signed-off-by: Daniel Walker > > > > --- > > include/linux/seqlock.h | 7 +++---- > > 1 file changed, 3 insertions(+), 4 deletions(-) > > > > Index: linux-2.6.23/include/linux/seqlock.h > > =================================================================== > > --- linux-2.6.23.orig/include/linux/seqlock.h > > +++ linux-2.6.23/include/linux/seqlock.h > > @@ -285,21 +285,20 @@ unsigned long __read_seqbegin_irqsave_ra > > unsigned long flags; > > > > local_irq_save(flags); > > - __read_seqbegin_raw(sl); > > return flags; > > } > > > > static __always_inline unsigned long __read_seqbegin_irqsave(seqlock_t *sl) > > { > > - __read_seqbegin(sl); > > return 0; > > } The above should be renamed. They have nothing to do with seqlocks now. > > > > #define read_seqbegin_irqsave(lock, flags) \ > > -do { \ > > +({ \ > > flags = PICK_SEQ_OP_RET(__read_seqbegin_irqsave_raw, \ > > __read_seqbegin_irqsave, lock); \ > > -} while (0) > > + read_seqbegin(lock); \ > > +}) Yes, definitely the raw and unraw functions should be called local_irqsave_raw or something else that makes this obvious to what it is doing. -- Steve - 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/