From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Message-ID: <5535B6C1.5040502@roeck-us.net> Date: Mon, 20 Apr 2015 19:32:33 -0700 From: Guenter Roeck MIME-Version: 1.0 Subject: Re: sparc64: Build failure due to commit f1600e549b94 (sparc: Make sparc64 use scalable lib/iommu-common.c functions) References: <55348BE1.4010305@roeck-us.net> <20150420.122519.1661605449214047938.davem@davemloft.net> <20150420164431.GA30837@roeck-us.net> <20150420.125050.2036067807685492178.davem@davemloft.net> <1429581250.9619.6.camel@ellerman.id.au> In-Reply-To: <1429581250.9619.6.camel@ellerman.id.au> Content-Type: text/plain; charset=utf-8; format=flowed List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , List-Archive: To: Michael Ellerman , David Miller 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 List-ID: On 04/20/2015 06:54 PM, Michael Ellerman wrote: > 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. Me not either, but, as you say, that is a different discussion. > > 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/ > I cover alpha:allmodconfig in my builds for -next, mainline, as well as all kernel.org stable releases and release candidates. This discussion is a good argument for enabling s390:allmodconfig as well. > 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. > Yes, but unfortunately only after the fact, though I don't see a means to avoid that. > >> But I guess that's a more involved longer-term discussion and I guess >> I'll apply Sowmini's patches for now. > Thanks! Guenter