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[2401:3900:2:1::2]) by mx.google.com with ESMTPS id m14si34223879pgd.326.2019.01.28.17.18.14 for (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Mon, 28 Jan 2019 17:18:15 -0800 (PST) Received-SPF: neutral (google.com: 2401:3900:2:1::2 is neither permitted nor denied by best guess record for domain of mpe@ellerman.id.au) client-ip=2401:3900:2:1::2; Authentication-Results: mx.google.com; spf=neutral (google.com: 2401:3900:2:1::2 is neither permitted nor denied by best guess record for domain of mpe@ellerman.id.au) smtp.mailfrom=mpe@ellerman.id.au Received: from authenticated.ozlabs.org (localhost [127.0.0.1]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange ECDHE (P-256) server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPSA id 43pTC33jzjz9sCX; Tue, 29 Jan 2019 12:18:06 +1100 (AEDT) From: Michael Ellerman To: Dave Hansen , Bjorn Helgaas , Dave Hansen Cc: Linux Kernel Mailing List , Dan Williams , Dave Jiang , zwisler@kernel.org, vishal.l.verma@intel.com, thomas.lendacky@amd.com, Andrew Morton , mhocko@suse.com, linux-nvdimm@lists.01.org, linux-mm@kvack.org, Huang Ying , Wu Fengguang , Borislav Petkov , baiyaowei@cmss.chinamobile.com, Takashi Iwai , Jerome Glisse , Benjamin Herrenschmidt , Paul Mackerras Subject: Re: [PATCH 1/5] mm/resource: return real error codes from walk failures In-Reply-To: <4898e064-5298-6a82-83ea-23d16f3dfb3d@intel.com> References: <20190124231441.37A4A305@viggo.jf.intel.com> <20190124231442.EFD29EE0@viggo.jf.intel.com> <4898e064-5298-6a82-83ea-23d16f3dfb3d@intel.com> Date: Tue, 29 Jan 2019 12:18:05 +1100 Message-ID: <87k1ios1ma.fsf@concordia.ellerman.id.au> MIME-Version: 1.0 Content-Type: text/plain X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: Dave Hansen writes: > On 1/25/19 1:02 PM, Bjorn Helgaas wrote: >>> @@ -453,7 +453,7 @@ int walk_system_ram_range(unsigned long >>> unsigned long flags; >>> struct resource res; >>> unsigned long pfn, end_pfn; >>> - int ret = -1; >>> + int ret = -EINVAL; >> Can you either make a similar change to the powerpc version of >> walk_system_ram_range() in arch/powerpc/mm/mem.c or explain why it's >> not needed? It *seems* like we'd want both versions of >> walk_system_ram_range() to behave similarly in this respect. > > Sure. A quick grep shows powerpc being the only other implementation. Ugh gross, why are we reimplementing it? ... Oh right, memblock vs iomem. We should fix that one day :/ > I'll just add this hunk: > >> diff -puN arch/powerpc/mm/mem.c~memory-hotplug-walk_system_ram_range-returns-neg-1 arch/powerpc/mm/mem.c >> --- a/arch/powerpc/mm/mem.c~memory-hotplug-walk_system_ram_range-returns-neg-1 2019-01-25 12:57:00.000004446 -0800 >> +++ b/arch/powerpc/mm/mem.c 2019-01-25 12:58:13.215004263 -0800 >> @@ -188,7 +188,7 @@ walk_system_ram_range(unsigned long star >> struct memblock_region *reg; >> unsigned long end_pfn = start_pfn + nr_pages; >> unsigned long tstart, tend; >> - int ret = -1; >> + int ret = -EINVAL; > > I'll also dust off the ol' cross-compiler and make sure I didn't > fat-finger anything. Modern Fedora & Ubuntu have packaged cross toolchains. Otherwise there's the kernel.org ones, or bootlin has versions with libc if you need it. Patch looks fine. That value could only get to userspace if we have no memory, which would be interesting. Acked-by: Michael Ellerman (powerpc) cheers