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[209.85.220.65]) by mx.google.com with SMTPS id f32sor23874266otb.171.2019.04.12.12.37.28 for (Google Transport Security); Fri, 12 Apr 2019 12:37:28 -0700 (PDT) Received-SPF: pass (google.com: domain of dan.j.williams@intel.com designates 209.85.220.65 as permitted sender) client-ip=209.85.220.65; Authentication-Results: mx.google.com; dkim=pass header.i=@intel-com.20150623.gappssmtp.com header.s=20150623 header.b=jwIaWv78; spf=pass (google.com: domain of dan.j.williams@intel.com designates 209.85.220.65 as permitted sender) smtp.mailfrom=dan.j.williams@intel.com; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=intel.com DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=intel-com.20150623.gappssmtp.com; s=20150623; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=tZfBY8D1WgXooJQRUiHKhSamR6kz9YpYQFKQ9Eq/1hU=; b=jwIaWv78fvkEa5rZbx+eP0fzYbqceSlvTJoR1XduCWAb2gsh8C3klYYgy/UEWlbg3W e1k5DE58xsWFRpnox+gDv2pxsyPeGd1VliXQdTqN/wjEe39t7A1LfOBY1Xw2oNp4IQFa izdMri970aizgvHVP7AGfoEDXy7apK6am+qaX0cHHnfXzrXeGMBd7PM/5URUlSE3Tjvv MU4YS4qovjxjhFGDBxrgmeU0ePJ2LKUa0pGMb+O0e+GfIn77BxF9oo+BRyxvHhW9LjqB xR/YJIrdWsl3PIAR/xzmCiHnNkkJXfmydSV2tKK7P3Oie3UkqJ0LeJfKW/5ZfXPUrnvS /+8A== X-Google-Smtp-Source: APXvYqzhThKbq5GHetTkjSO5HdGMCT2FjO95YYhE57pp/4fhw00RFxMp33Lhq/TjtVDDMqbk9Vdgq3NV9eBZbTTkHEY= X-Received: by 2002:a9d:3f4b:: with SMTP id m69mr37976108otc.246.1555097847859; Fri, 12 Apr 2019 12:37:27 -0700 (PDT) MIME-Version: 1.0 References: <25525e4dab6ebc49e233f21f7c29821223431647.1555093412.git.robin.murphy@arm.com> In-Reply-To: <25525e4dab6ebc49e233f21f7c29821223431647.1555093412.git.robin.murphy@arm.com> From: Dan Williams Date: Fri, 12 Apr 2019 12:37:16 -0700 Message-ID: Subject: Re: [PATCH RESEND 3/3] mm: introduce ARCH_HAS_PTE_DEVMAP To: Robin Murphy Cc: Linux MM , "Weiny, Ira" , =?UTF-8?B?SsOpcsO0bWUgR2xpc3Nl?= , "Oliver O'Halloran" , X86 ML , linuxppc-dev , Anshuman Khandual , Linux Kernel Mailing List Content-Type: text/plain; charset="UTF-8" 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: On Fri, Apr 12, 2019 at 12:02 PM Robin Murphy wrote: > > ARCH_HAS_ZONE_DEVICE is somewhat meaningless in itself, and combined > with the long-out-of-date comment can lead to the impression than an > architecture may just enable it (since __add_pages() now "comprehends > device memory" for itself) and expect things to work. > > In practice, however, ZONE_DEVICE users have little chance of > functioning correctly without __HAVE_ARCH_PTE_DEVMAP, so let's clean > that up the same way as ARCH_HAS_PTE_SPECIAL and make it the proper > dependency so the real situation is clearer. Looks good to me. Acked-by: Dan Williams