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[77.88.29.217]) by mx.google.com with ESMTP id l22si1119619lfh.36.2019.05.15.01.48.34 for ; Wed, 15 May 2019 01:48:34 -0700 (PDT) Received-SPF: pass (google.com: domain of khlebnikov@yandex-team.ru designates 77.88.29.217 as permitted sender) client-ip=77.88.29.217; Authentication-Results: mx.google.com; dkim=pass header.i=@yandex-team.ru header.s=default header.b=xS6pYk6l; spf=pass (google.com: domain of khlebnikov@yandex-team.ru designates 77.88.29.217 as permitted sender) smtp.mailfrom=khlebnikov@yandex-team.ru; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=yandex-team.ru Received: from mxbackcorp1j.mail.yandex.net (mxbackcorp1j.mail.yandex.net [IPv6:2a02:6b8:0:1619::162]) by forwardcorp1p.mail.yandex.net (Yandex) with ESMTP id E97EF2E146D; Wed, 15 May 2019 11:48:33 +0300 (MSK) Received: from smtpcorp1o.mail.yandex.net (smtpcorp1o.mail.yandex.net [2a02:6b8:0:1a2d::30]) by mxbackcorp1j.mail.yandex.net (nwsmtp/Yandex) with ESMTP id Q7pQ1sTs55-mXwKadUT; Wed, 15 May 2019 11:48:33 +0300 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=yandex-team.ru; s=default; t=1557910113; bh=RBKOGGXjvQMTQzfr1KxZ/9oyUSl618uUSUuLqd4U4J4=; h=In-Reply-To:Message-ID:From:Date:References:To:Subject:Cc; b=xS6pYk6lclpU7VNMA86o90Cjw5stbFWI+4tB+0YsgkUrheiouBQ8AFz8MpyH3KX6B cYl8QrQFZIGVKhNgLsQ5GI7hC5vZalPybRoqEZphXJ6kxTMy+pJlDcuospumbfhH/6 AX9OFu7taypLf891OGXJ8oBpDBEjmuIz6A49Iw8Q= Authentication-Results: mxbackcorp1j.mail.yandex.net; dkim=pass header.i=@yandex-team.ru Received: from dynamic-red.dhcp.yndx.net (dynamic-red.dhcp.yndx.net [2a02:6b8:0:40c:ed19:3833:7ce1:2324]) by smtpcorp1o.mail.yandex.net (nwsmtp/Yandex) with ESMTPSA id F0Vfe9DM2Y-mXlCWMAt; Wed, 15 May 2019 11:48:33 +0300 (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (Client certificate not present) Subject: Re: mm: use down_read_killable for locking mmap_sem in access_remote_vm To: =?UTF-8?Q?Michal_Koutn=c3=bd?= Cc: akpm@linux-foundation.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, oleg@redhat.com References: <20190515083825.GJ13687@blackbody.suse.cz> From: Konstantin Khlebnikov Message-ID: <11ee83c8-5f0f-0950-a588-037bdcf9084e@yandex-team.ru> Date: Wed, 15 May 2019 11:48:32 +0300 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.6.1 MIME-Version: 1.0 In-Reply-To: <20190515083825.GJ13687@blackbody.suse.cz> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Language: en-CA Content-Transfer-Encoding: 8bit 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 15.05.2019 11:38, Michal Koutný wrote: > Hi, > making this holder of mmap_sem killable was for the reasons of /proc/... > diagnostics was an idea I was pondeering too. However, I think the > approach of pretending we read 0 bytes is not correct. The API would IMO > need to be extended to allow pass a result such as EINTR to the end > caller. > Why do you think it's safe to return just 0? This function ignores any error like reading from unmapped area and returns only size of successful transfer. It never returned any error codes. > > Michal >