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=-8.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,USER_AGENT_MUTT autolearn=unavailable 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 E4734C10F0B for ; Tue, 26 Feb 2019 06:06:45 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id ABDE4213A2 for ; Tue, 26 Feb 2019 06:06:45 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org ABDE4213A2 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 483F48E0003; Tue, 26 Feb 2019 01:06:45 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 433C58E0002; Tue, 26 Feb 2019 01:06:45 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 322748E0003; Tue, 26 Feb 2019 01:06:45 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from mail-qt1-f200.google.com (mail-qt1-f200.google.com [209.85.160.200]) by kanga.kvack.org (Postfix) with ESMTP id 0C2898E0002 for ; Tue, 26 Feb 2019 01:06:45 -0500 (EST) Received: by mail-qt1-f200.google.com with SMTP id d49so11444437qtd.15 for ; Mon, 25 Feb 2019 22:06:45 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-original-authentication-results:x-gm-message-state:date:from:to :cc:subject:message-id:references:mime-version:content-disposition :in-reply-to:user-agent; bh=Xmw8Qb+EIreCEt76B4u1+5aPg48uJFZCiCPoEreFv8s=; b=A4PsAu2MsSvJN2hx+uLGMsTizYr+YlDPb9EnCiNe4nGmtMBqdpn4VH/mKzC/N0SmPk +EpiXA2QbZJZIOKQnsRBq9V1AAfidclkxCXngNO4A5tXrpacii+DlEKsQ9xm7dXhas1m 6eBn3rSlEcfAdD1mLYmUeO8dMR6lkWJShQhf36HhToSxNCMFzr+qHM9UIZrcx3ELTHSw aJHGp4ij6bXvOei/omg8Fzf4IEpmI5VS1N99nqsI6pjYsKVTeVXzY3cGaqkJu1WXopTi L29KvcE/lJmcsrJiFRSg5yrk/cYUv4/XK0qTEqxQXt8gNun5Y9BvrRRgrSfvPATcR7vA XGbw== X-Original-Authentication-Results: mx.google.com; spf=pass (google.com: domain of peterx@redhat.com designates 209.132.183.28 as permitted sender) smtp.mailfrom=peterx@redhat.com; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=redhat.com X-Gm-Message-State: AHQUAuYIuveC8e7oXKzjjkzUSO3umK739CyVWAokGtKTtzTGdo3sVVIR ds8CsmKXDuX3nDlAgCd+75wUNNZbJI4YodJVfWmBXaQTFroRDnBMYqJSXNxQAofMaR2waul+fNh HyvnzoS24EUsqhZwb7ro8YoDd+nOMLg903kEChuDH4p4KvipUbs3XJnRIWPFycyKjOg== X-Received: by 2002:a37:a105:: with SMTP id k5mr15657659qke.32.1551161204712; Mon, 25 Feb 2019 22:06:44 -0800 (PST) X-Google-Smtp-Source: AHgI3IZ6ESetwq6A5k9m//LZVFUnk3nCVdFyWnlBDecuHbeyeETFI74Q9UcDamTf+6fCD6NC/Ygn X-Received: by 2002:a37:a105:: with SMTP id k5mr15657620qke.32.1551161203719; Mon, 25 Feb 2019 22:06:43 -0800 (PST) ARC-Seal: i=1; a=rsa-sha256; t=1551161203; cv=none; d=google.com; s=arc-20160816; b=PKfaS6YffgzpGu+2rK15FDf4ZEaq+Xix5uOB6i6fFAR+aVEGudBIk2ivleoOUmW/O/ JBO0wuJa3BH4oI1yyByTvZ+NupH2DWoNP2eEkTtqegDfd+zsBm5SNS8h3ClOB1FLK2v1 n45hBgDvuGLyW4bhEdA7gNOdk6F+YBQN0gRuCdSR8IQn9Yr+DDghY76zwhV3vevxp6P/ poUGwr7Q7m8hmaK08Clw1XxP8YLSGwUCcTZvPiyG5kA4kLyNDG6vGLDvEx+BZOErgZB3 PGdfGnR6/yxiy6ImbqhZACOCPQV7qQYVATINPV+mrIYV+GvK5Glzsu9KLptYR8bThadT n05g== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=user-agent:in-reply-to:content-disposition:mime-version:references :message-id:subject:cc:to:from:date; bh=Xmw8Qb+EIreCEt76B4u1+5aPg48uJFZCiCPoEreFv8s=; b=zy82d4F2DtKDh/yuPL17RlLPzkP4u4GO41WIkYKfplyHO8rx1ibw3Qbc7m/6Prd9F7 UeFLx2qt6sikQ8YbOazUVsO0tnJ/y8Oflj/e1qPGOkYxeb8B+f2E49ejYgJoN2FgY9UZ EPWJLrjX3PtnwhPzZMdaU2sU4bzgFwnYFr9WDOh48lvBn67LcI6ARoc9rmgsW83r7iMX 3+t7FgldorhT4R801xpZS4YWQ8cgylwIecOM6eRb4LM0OzQpr3xQSo3ojZhc8B0qzcVt 7Wr/xkf+JMwfSXof6pK25XrDQR/G/7iQU84eeZ8oEbnR95GPtDNzwFWdyRBNlFlTd971 pGxg== ARC-Authentication-Results: i=1; mx.google.com; spf=pass (google.com: domain of peterx@redhat.com designates 209.132.183.28 as permitted sender) smtp.mailfrom=peterx@redhat.com; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=redhat.com Received: from mx1.redhat.com (mx1.redhat.com. [209.132.183.28]) by mx.google.com with ESMTPS id n6si1908722qtk.21.2019.02.25.22.06.43 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 25 Feb 2019 22:06:43 -0800 (PST) Received-SPF: pass (google.com: domain of peterx@redhat.com designates 209.132.183.28 as permitted sender) client-ip=209.132.183.28; Authentication-Results: mx.google.com; spf=pass (google.com: domain of peterx@redhat.com designates 209.132.183.28 as permitted sender) smtp.mailfrom=peterx@redhat.com; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=redhat.com Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 71E6A3082163; Tue, 26 Feb 2019 06:06:42 +0000 (UTC) Received: from xz-x1 (dhcp-14-116.nay.redhat.com [10.66.14.116]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 462E460BE7; Tue, 26 Feb 2019 06:06:30 +0000 (UTC) Date: Tue, 26 Feb 2019 14:06:27 +0800 From: Peter Xu To: Mike Rapoport Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, David Hildenbrand , Hugh Dickins , Maya Gokhale , Jerome Glisse , Pavel Emelyanov , Johannes Weiner , Martin Cracauer , Shaohua Li , Marty McFadden , Andrea Arcangeli , Mike Kravetz , Denis Plotnikov , Mike Rapoport , Mel Gorman , "Kirill A . Shutemov" , "Dr . David Alan Gilbert" , Rik van Riel Subject: Re: [PATCH v2 20/26] userfaultfd: wp: support write protection for userfault vma range Message-ID: <20190226060627.GG13653@xz-x1> References: <20190212025632.28946-1-peterx@redhat.com> <20190212025632.28946-21-peterx@redhat.com> <20190225205233.GC10454@rapoport-lnx> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20190225205233.GC10454@rapoport-lnx> User-Agent: Mutt/1.10.1 (2018-07-13) X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.47]); Tue, 26 Feb 2019 06:06:42 +0000 (UTC) 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 Mon, Feb 25, 2019 at 10:52:34PM +0200, Mike Rapoport wrote: > On Tue, Feb 12, 2019 at 10:56:26AM +0800, Peter Xu wrote: > > From: Shaohua Li > > > > Add API to enable/disable writeprotect a vma range. Unlike mprotect, > > this doesn't split/merge vmas. > > > > Cc: Andrea Arcangeli > > Cc: Rik van Riel > > Cc: Kirill A. Shutemov > > Cc: Mel Gorman > > Cc: Hugh Dickins > > Cc: Johannes Weiner > > Signed-off-by: Shaohua Li > > Signed-off-by: Andrea Arcangeli > > [peterx: > > - use the helper to find VMA; > > - return -ENOENT if not found to match mcopy case; > > - use the new MM_CP_UFFD_WP* flags for change_protection > > - check against mmap_changing for failures] > > Signed-off-by: Peter Xu > > --- > > include/linux/userfaultfd_k.h | 3 ++ > > mm/userfaultfd.c | 54 +++++++++++++++++++++++++++++++++++ > > 2 files changed, 57 insertions(+) > > > > diff --git a/include/linux/userfaultfd_k.h b/include/linux/userfaultfd_k.h > > index 765ce884cec0..8f6e6ed544fb 100644 > > --- a/include/linux/userfaultfd_k.h > > +++ b/include/linux/userfaultfd_k.h > > @@ -39,6 +39,9 @@ extern ssize_t mfill_zeropage(struct mm_struct *dst_mm, > > unsigned long dst_start, > > unsigned long len, > > bool *mmap_changing); > > +extern int mwriteprotect_range(struct mm_struct *dst_mm, > > + unsigned long start, unsigned long len, > > + bool enable_wp, bool *mmap_changing); > > > > /* mm helpers */ > > static inline bool is_mergeable_vm_userfaultfd_ctx(struct vm_area_struct *vma, > > diff --git a/mm/userfaultfd.c b/mm/userfaultfd.c > > index fefa81c301b7..529d180bb4d7 100644 > > --- a/mm/userfaultfd.c > > +++ b/mm/userfaultfd.c > > @@ -639,3 +639,57 @@ ssize_t mfill_zeropage(struct mm_struct *dst_mm, unsigned long start, > > { > > return __mcopy_atomic(dst_mm, start, 0, len, true, mmap_changing, 0); > > } > > + > > +int mwriteprotect_range(struct mm_struct *dst_mm, unsigned long start, > > + unsigned long len, bool enable_wp, bool *mmap_changing) > > +{ > > + struct vm_area_struct *dst_vma; > > + pgprot_t newprot; > > + int err; > > + > > + /* > > + * Sanitize the command parameters: > > + */ > > + BUG_ON(start & ~PAGE_MASK); > > + BUG_ON(len & ~PAGE_MASK); > > + > > + /* Does the address range wrap, or is the span zero-sized? */ > > + BUG_ON(start + len <= start); > > I'd replace these BUG_ON()s with > > if (WARN_ON()) > return -EINVAL; I believe BUG_ON() is used because these parameters should have been checked in userfaultfd_writeprotect() already by the common validate_range() even before calling mwriteprotect_range(). So I'm fine with the WARN_ON() approach but I'd slightly prefer to simply keep the patch as is to keep Jerome's r-b if you won't disagree. :) Thanks, -- Peter Xu