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=-0.8 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no 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 050EBC54E49 for ; Fri, 8 May 2020 18:21:50 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id A1495208CA for ; Fri, 8 May 2020 18:21:49 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="Fho/vCig" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org A1495208CA Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id CF7BD8E0005; Fri, 8 May 2020 14:21:48 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id CA9348E0003; Fri, 8 May 2020 14:21:48 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id B976C8E0005; Fri, 8 May 2020 14:21:48 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0197.hostedemail.com [216.40.44.197]) by kanga.kvack.org (Postfix) with ESMTP id A345F8E0003 for ; Fri, 8 May 2020 14:21:48 -0400 (EDT) Received: from smtpin01.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with ESMTP id 5B3218248047 for ; Fri, 8 May 2020 18:21:48 +0000 (UTC) X-FDA: 76794370296.01.horn64_fb85b40c3846 X-HE-Tag: horn64_fb85b40c3846 X-Filterd-Recvd-Size: 4857 Received: from mail-pg1-f194.google.com (mail-pg1-f194.google.com [209.85.215.194]) by imf19.hostedemail.com (Postfix) with ESMTP for ; Fri, 8 May 2020 18:21:47 +0000 (UTC) Received: by mail-pg1-f194.google.com with SMTP id f6so1239499pgm.1 for ; Fri, 08 May 2020 11:21:47 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=sender:date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=gV/o9nW1NZlOEYAKRGRfdUGcdnKxPdO6FjHvoQSmtS8=; b=Fho/vCig3jvc0rFGu22IQlVl0LbUgnslTrEacpTD1DxEbw4rblrrsfiwtfEvDCFkt3 eL2bJ8UcwqXj8KZ6VxlgZwqxHze8iuf1gMPR1O0o6SCnDBDnvpE24//uqJE7XLFhKQIP OG9SlLp3PMTT9+tCdEeQFKiFPaIJsY4pcCMj3ZeeLatNX6nmXX2ih/k8EWHWSc6vwArH QzBbqr/bUS9StnHBf1q/zAV0hyXHk6+uX/Fg5fnVEO+XPTXtJYd2Rw6wWi+m0PrRexhv xphOHgxD2mSpxPoRUuzbrZSuonrvtaG/nvzgCAoYgh2LmmnlRA0kO+PRrDbAvYhGDiuu 0Cug== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:sender:date:from:to:cc:subject:message-id :references:mime-version:content-disposition:in-reply-to; bh=gV/o9nW1NZlOEYAKRGRfdUGcdnKxPdO6FjHvoQSmtS8=; b=NcYSneONrESoHF6v+cERy1CJuAuhO+nJea7JceUoukslQACyZKyGqG7XPUY3+TB4kQ EGoUI26i2u/TPeZUoc3ifhXOH+tHAVgvcgPI9s28310EvM4gYgK1MwGqRoNwJtBjSHEV Ixk/fViOtMboe6Hb+giXqEUClVEfNy5+YwMmrq0Xiw2dDF1peVuwcdrZ2xi6wxM/OB4x wp42Z9pIUHEgvKozynqtuxgJ57aXp9znK9Jx06VzGzONRQPMtgUABT7XZaS0Uu7wJsf6 frUQKl2KdhEcV3gQBGP+USsEfxndb3nRJLSTIlOq9bJXINVuA5bphzeVQYAqP2mdj3Pd vWjw== X-Gm-Message-State: AGi0PubaEN0UJIrseQziHPZJYN7oRDqsvS2JNi8dpdhWkxguWXzZ17j+ jXrC5asxxYe7+V2LISW6zRA= X-Google-Smtp-Source: APiQypKFXwPLf4reDS9wBZw91ohMCcZQpLOa4hDF/CkXvGYds+TKhWq/NPgguH9tO5AmSyf1JFBi8w== X-Received: by 2002:a63:1f62:: with SMTP id q34mr3131580pgm.197.1588962106785; Fri, 08 May 2020 11:21:46 -0700 (PDT) Received: from google.com ([2620:15c:211:1:3e01:2939:5992:52da]) by smtp.gmail.com with ESMTPSA id u8sm2875545pjy.16.2020.05.08.11.21.45 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 08 May 2020 11:21:45 -0700 (PDT) Date: Fri, 8 May 2020 11:21:43 -0700 From: Minchan Kim To: Vlastimil Babka Cc: Andrew Morton , LKML , linux-mm , linux-api@vger.kernel.org, oleksandr@redhat.com, Suren Baghdasaryan , Tim Murray , Daniel Colascione , Sandeep Patil , Sonny Rao , Brian Geffon , Michal Hocko , Johannes Weiner , Shakeel Butt , John Dias , Joel Fernandes , Jann Horn , alexander.h.duyck@linux.intel.com, sj38.park@gmail.com, Jens Axboe Subject: Re: [PATCH v7 1/7] mm: pass task and mm to do_madvise Message-ID: <20200508182143.GA101195@google.com> References: <20200302193630.68771-1-minchan@kernel.org> <20200302193630.68771-2-minchan@kernel.org> <2a767d50-4034-da8c-c40c-280e0dda910e@suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <2a767d50-4034-da8c-c40c-280e0dda910e@suse.cz> 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 Thu, Mar 05, 2020 at 04:48:12PM +0100, Vlastimil Babka wrote: > On 3/2/20 8:36 PM, Minchan Kim wrote: > > In upcoming patches, do_madvise will be called from external process > > context so we shouldn't asssume "current" is always hinted process's > > task_struct. > > > > Furthermore, we couldn't access mm_struct via task->mm > > once it's verified by access_mm which will be introduced in next > > patch[1]. > > I would suggest to replace with: > > Furthermore, we must not access mm_struct via task->mm, but obtain it via > access_mm() once (in the following patch) and only use that pointer [1], so pass > it to do_madvise() as well. Note the vma->vm_mm pointers are safe, so we can use > them further down the call stack. > > > And let's pass *current* and current->mm as arguments of > > do_madvise so it shouldn't change existing behavior but prepare > > next patch to make review easy. > > > > Note: io_madvise pass NULL as target_task argument of do_madvise > > because it couldn't know who is target. > > can't Andrew already picked up your suggestion except "can't" part. I don't think it's enough to resend fix it so I will leave it as-is.