From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id B4CCAC433DF for ; Mon, 18 May 2020 10:42:54 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 90936207ED for ; Mon, 18 May 2020 10:42:54 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 90936207ED Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=suse.cz Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 33E62900003; Mon, 18 May 2020 06:42:54 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 2A064900002; Mon, 18 May 2020 06:42:54 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 16946900003; Mon, 18 May 2020 06:42:54 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0198.hostedemail.com [216.40.44.198]) by kanga.kvack.org (Postfix) with ESMTP id ED053900002 for ; Mon, 18 May 2020 06:42:53 -0400 (EDT) Received: from smtpin02.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with ESMTP id AA6542C8B for ; Mon, 18 May 2020 10:42:53 +0000 (UTC) X-FDA: 76829501826.02.hand66_53721f0cd6f3a X-HE-Tag: hand66_53721f0cd6f3a X-Filterd-Recvd-Size: 2151 Received: from mx2.suse.de (mx2.suse.de [195.135.220.15]) by imf38.hostedemail.com (Postfix) with ESMTP for ; Mon, 18 May 2020 10:42:53 +0000 (UTC) X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx2.suse.de (Postfix) with ESMTP id 7C680AA4F; Mon, 18 May 2020 10:42:54 +0000 (UTC) Subject: Re: [PATCH v5 07/10] mmap locking API: add mmap_read_trylock_non_owner() To: Michel Lespinasse , Andrew Morton , linux-mm Cc: LKML , Peter Zijlstra , Laurent Dufour , Matthew Wilcox , Liam Howlett , Jerome Glisse , Davidlohr Bueso , David Rientjes , Hugh Dickins , Ying Han , Jason Gunthorpe , Daniel Jordan References: <20200422001422.232330-1-walken@google.com> <20200422001422.232330-8-walken@google.com> From: Vlastimil Babka Message-ID: Date: Mon, 18 May 2020 12:42:50 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.7.0 MIME-Version: 1.0 In-Reply-To: <20200422001422.232330-8-walken@google.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit 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 4/22/20 2:14 AM, Michel Lespinasse wrote: > Add a couple APIs used by kernel/bpf/stackmap.c only: > - mmap_read_trylock_non_owner() > - mmap_read_unlock_non_owner() (may be called from a work queue). > > It's still not ideal that bpf/stackmap subverts the lock ownership > in this way. Thanks to Peter Zijlstra for suggesting this API as the > least-ugly way of addressing this in the short term. > > Signed-off-by: Michel Lespinasse > Reviewed-by: Daniel Jordan Ugh... oh well. Reviewed-by: Vlastimil Babka