Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932562AbWCCXn0 (ORCPT ); Fri, 3 Mar 2006 18:43:26 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932595AbWCCXnZ (ORCPT ); Fri, 3 Mar 2006 18:43:25 -0500 Received: from mailout.stusta.mhn.de ([141.84.69.5]:25101 "HELO mailout.stusta.mhn.de") by vger.kernel.org with SMTP id S932562AbWCCXnY (ORCPT ); Fri, 3 Mar 2006 18:43:24 -0500 Date: Sat, 4 Mar 2006 00:43:23 +0100 From: Adrian Bunk To: Linus Torvalds Cc: Andrew Morton , geert@linux-m68k.org, zippel@linux-m68k.org, linux-m68k@vger.kernel.org, Linux Kernel Mailing List , Nick Piggin Subject: Re: 2.6.16-rc regression: m68k CONFIG_RMW_INSNS=n compile broken Message-ID: <20060303234323.GF9295@stusta.de> References: <20060303230149.GB9295@stusta.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.11+cvs20060126 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1659 Lines: 48 On Fri, Mar 03, 2006 at 03:22:42PM -0800, Linus Torvalds wrote: > > > On Sat, 4 Mar 2006, Adrian Bunk wrote: > > > > It seems the problem is that in the CONFIG_RMW_INSNS=n case, there's no > > cmpxchg #define in include/asm-m68k/system.h required for the > > atomic_add_unless #define in include/asm-m68k/atomic.h. > > Hmm. It seems like it never has been there.. Do you know what brought this > on? Was it Nick's RCU changes from "rcuref_dec_and_test()" to > "atomic_dec_and_test()" and friends? It was Nick's commit 8426e1f6af0fd7f44d040af7263750c5a52f3cc3 that added atomic_inc_not_zero(), and Nick's patch that changed fs/file_table.c from rcuref_dec_and_test() to atomic_dec_and_test() exposed this problem. > Judging by your error messages, I _think_ it's the "atomic_inc_not_zero()" > that gets expanded to a cmpxchg() that simply doesn't exist on m68k and > never has. Exactly, that's what I wanted to say in my report. > I guess we've never depended on cmpxchg before. Or am I missing something? It seems this is the case. And as far as I can see, m68k is the only architecture where cmpxchg isn't always available. > Linus cu Adrian -- "Is there not promise of rain?" Ling Tan asked suddenly out of the darkness. There had been need of rain for many days. "Only a promise," Lao Er said. Pearl S. Buck - Dragon Seed - 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/