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[195.135.220.15]) by mx.google.com with ESMTPS id t45si958228eda.235.2019.05.15.01.38.28 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 15 May 2019 01:38:29 -0700 (PDT) Received-SPF: pass (google.com: domain of mkoutny@suse.com designates 195.135.220.15 as permitted sender) client-ip=195.135.220.15; Authentication-Results: mx.google.com; spf=pass (google.com: domain of mkoutny@suse.com designates 195.135.220.15 as permitted sender) smtp.mailfrom=mkoutny@suse.com X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx1.suse.de (Postfix) with ESMTP id B52BAAF95; Wed, 15 May 2019 08:38:27 +0000 (UTC) Date: Wed, 15 May 2019 10:38:26 +0200 From: Michal =?iso-8859-1?Q?Koutn=FD?= To: khlebnikov@yandex-team.ru Cc: akpm@linux-foundation.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, oleg@redhat.com Subject: Re: mm: use down_read_killable for locking mmap_sem in access_remote_vm Message-ID: <20190515083825.GJ13687@blackbody.suse.cz> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="451BZW+OUuJBCAYj" Content-Disposition: inline In-Reply-To: <155790847881.2798.7160461383704600177.stgit@buzz> User-Agent: Mutt/1.10.1 (2018-07-13) 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: --451BZW+OUuJBCAYj Content-Type: text/plain; charset=us-ascii Content-Disposition: inline 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? Michal --451BZW+OUuJBCAYj Content-Type: application/pgp-signature; name="signature.asc" Content-Description: Digital signature -----BEGIN PGP SIGNATURE----- iQIzBAEBCAAdFiEE+amhwRV4jZeXdUhoK2l36XSZ9y4FAlzbz/sACgkQK2l36XSZ 9y72Dw//WSCQl+uR7hQKCcZgc6M3EGW5FhKKiFTfagIYPeGFx8co6rAG2XFCBn89 PiCHJjcjY5BtRaCnLV/AmLbSGSj/j7aX0FIM/nKkP7z78HTrSBjkd30HIXV1Vig8 wQY4JGC5bK2rUkd/D5Fjjrg93wMvwRfyj3wZ6/dXObPU8tfbrbOTeD+JNFlk1WZf WitkTbX3mD/xC3P3ItZ9+mTRXK+0MCMu/Bazf90yDFRB2uXvA788CTGVzsqzyfpG vkZmBDTzT/jJJhYKd4gR4ecaQbD3zzZdJiz5AEZFGJFSpK6nwYXz9jarjIWP2T6e OSZ4mGj+RjL3YBk9sqNgHPXMMS6IQoIgbpjVxwQlNN+6sSfGVm4qVGLn5N+69LwR iQtCQSv2JS5afnWSaahWQsxzvmkE/6OC6Qs1D1EdclP7ph1PgrkV2NJ+0VVBZfRA m0VNzZ6APLLoPc7yGaBP36yw6pjgycrVQaDtgZa1hqf1bpLnoqwrSlUQTTN2475Q ig/ZEnDjlB/X85OkdEB26SLw5CtH35EL64DhfNU9l1dZ5Ygw5O4nOevkPwL2XC3F mtftFgxxtFN2zDqg3s5gz7K5AAef7jn9TySNze2l7OVFwfpd96b8SXfyPxRMOgcy aUFG3qyAdXEoPQHQPWtTrKsnhbu+qNCaIbhxZAL9j5iVKnHc/cA= =vcUI -----END PGP SIGNATURE----- --451BZW+OUuJBCAYj--