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X-CSE-ConnectionGUID: wtlSwzLKRLyiOUfygwVGcg== X-CSE-MsgGUID: 3WZDo50EQgeD5QQ2bXPULg== X-IronPort-AV: E=McAfee;i="6800,10657,11895"; a="88952395" X-IronPort-AV: E=Sophos;i="6.25,260,1779174000"; d="scan'208";a="88952395" Received: from orviesa002.jf.intel.com ([10.64.159.142]) by fmvoesa108.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 03 Sep 2026 07:09:11 -0700 X-CSE-ConnectionGUID: sqkLtLQkSrG19ohlwpkNug== X-CSE-MsgGUID: NhEX0h3dQKKL3kmHczyrDA== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.25,260,1779174000"; d="scan'208";a="299605415" Received: from jmaxwel1-mobl.amr.corp.intel.com (HELO [10.125.110.172]) ([10.125.110.172]) by orviesa002-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 03 Sep 2026 07:09:10 -0700 Message-ID: <1aa2b2a6-b068-4856-97ef-91ab848f01c3@intel.com> Date: Thu, 3 Sep 2026 07:09:09 -0700 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v7 1/3] mm: make persistent huge zero folio read-only To: Mike Rapoport Cc: Xueyuan Chen , akpm@linux-foundation.org, david@kernel.org, ljs@kernel.org, usama.arif@linux.dev, ziy@nvidia.com, baolin.wang@linux.alibaba.com, liam@infradead.org, nico.pache@linux.dev, ryan.roberts@arm.com, dev.jain@arm.com, baohua@kernel.org, lance.yang@linux.dev, kas@kernel.org, catalin.marinas@arm.com, will@kernel.org, mark.rutland@arm.com, linux-arm-kernel@lists.infradead.org, tglx@kernel.org, mingo@redhat.com, bp@alien8.de, dave.hansen@linux.intel.com, x86@kernel.org, hpa@zytor.com, luto@kernel.org, peterz@infradead.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org References: <20260901151818.3191443-1-xueyuan.chen21@gmail.com> <20260901151818.3191443-2-xueyuan.chen21@gmail.com> <5026dbec-0b71-4408-a78a-484a4b8e77dd@intel.com> From: Dave Hansen Content-Language: en-US Autocrypt: addr=dave.hansen@intel.com; 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charset=UTF-8 Content-Transfer-Encoding: 7bit X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.9.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260903_070911_467043_94E97CA9 X-CRM114-Status: GOOD ( 11.38 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On 9/3/26 02:20, Mike Rapoport wrote: > On Wed, Sep 02, 2026 at 01:59:15PM -0700, Dave Hansen wrote: >> On 9/1/26 08:18, Xueyuan Chen wrote: >>> +static inline int set_direct_map_ro(struct page *page, unsigned int nr) >>> +{ >>> + return 0; >>> +} >> I still really think the stub here needs to return an error *or* the >> thing needs to just be void and tell folks that they can't know whether >> it worked or not. > All other stubs return 0 here when an arch does not support set_direct_map. > I'm for keeping them all consistent and fixing that technical debt as a > whole rather than creating a one-off here. Oof. I didn't realize the set_direct_map_*() functions all did this. I do think it's generally a bad idea, and I'm also OK if it is not fixed up here.