From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from ozlabs.org (ozlabs.org [103.22.144.67]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id A39E61A0028 for ; Tue, 21 Apr 2015 11:54:11 +1000 (AEST) Message-ID: <1429581250.9619.6.camel@ellerman.id.au> Subject: Re: sparc64: Build failure due to commit f1600e549b94 (sparc: Make sparc64 use scalable lib/iommu-common.c functions) From: Michael Ellerman To: David Miller Date: Tue, 21 Apr 2015 11:54:10 +1000 In-Reply-To: <20150420.125050.2036067807685492178.davem@davemloft.net> References: <55348BE1.4010305@roeck-us.net> <20150420.122519.1661605449214047938.davem@davemloft.net> <20150420164431.GA30837@roeck-us.net> <20150420.125050.2036067807685492178.davem@davemloft.net> Content-Type: text/plain; charset="UTF-8" Mime-Version: 1.0 Cc: linux-s390@vger.kernel.org, aik@au1.ibm.com, sowmini.varadhan@oracle.com, anton@au1.ibm.com, heiko.carstens@de.ibm.com, linux-kernel@vger.kernel.org, schwidefsky@de.ibm.com, paulus@samba.org, sparclinux@vger.kernel.org, linux390@de.ibm.com, linuxppc-dev@lists.ozlabs.org, linux@roeck-us.net List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Mon, 2015-04-20 at 12:50 -0400, David Miller wrote: > From: Guenter Roeck > Date: Mon, 20 Apr 2015 09:44:31 -0700 > > > On Mon, Apr 20, 2015 at 12:25:19PM -0400, David Miller wrote: > >> From: Guenter Roeck > >> Date: Sun, 19 Apr 2015 22:17:21 -0700 > >> > >> > The debug option is intended for all _other_ architectures, to > >> > ensure that changes made for those don't break alpha/s390 > >> > builds. alpha/s390 have ARCH_NEEDS_WEAK_PER_CPU and don't need the > >> > debug option. > >> > >> Ironically this would not create a build failure for the architectures > >> where this matters, because only powerpc has the like named percpu > >> symbol. > >> > >> So it's not really meeting the stated objective in this case. > > > > Yes, that is correct; it can only find problems in non-architecture > > code, and on the downside produces false positives and thus build errors > > like this one. > > > > Which makes the fix a bit philosophical. Rename iommu_pool_hash in > > iommu-common, or drop DEBUG_FORCE_WEAK_PER_CPU. I would rename > > iommu_pool_hash, but that is just me. Ultimately, I don't really > > care one way or another, as long as the problem gets fixed. > > If nightly builds of s390 and alpha, the two platforms where this > matters, are being done as reported in this thread, then I really > don't see the value in DEBUG_FORCE_WEAK_PER_CPU. We do an s390 allmodconfig for every linux-next release: http://kisskb.ellerman.id.au/kisskb/target/573/ And also for Linus' tree: http://kisskb.ellerman.id.au/kisskb/target/568/ We don't have alpha allmodconfig enabled, though we could, but we do build the defconfig: http://kisskb.ellerman.id.au/kisskb/target/2499/ http://kisskb.ellerman.id.au/kisskb/target/2494/ So I think that should be sufficient to catch any percpus that are introduced in generic code with the same name as s390/alpha variables. > But I guess that's a more involved longer-term discussion and I guess > I'll apply Sowmini's patches for now. Yeah I guess it is. Thanks for merging the fix. cheers