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=-9.9 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT 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 87E09C11D0C for ; Thu, 20 Feb 2020 16:32:18 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 5D40C208E4 for ; Thu, 20 Feb 2020 16:32:18 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="OVF22Jqo" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729027AbgBTQcR (ORCPT ); Thu, 20 Feb 2020 11:32:17 -0500 Received: from us-smtp-2.mimecast.com ([205.139.110.61]:29359 "EHLO us-smtp-delivery-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1728937AbgBTQbq (ORCPT ); Thu, 20 Feb 2020 11:31:46 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1582216305; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=gp1yBY+tfz3ASfvSkHX3QDXKz8JE+vKM1ZqbokypNuk=; b=OVF22Jqoz0C5Ng/ReS9vsZekukg0F+iavkNkEi3LP19/OMpkIclKpuxb9i8BA6Xym6ODRX BnRPvwUn0llVNLA8p6Uiw0lkQFzSey674OJyLQY8zLQwRATbMdOyUR9r3er4XttbYExywz J1+X0lv5OwuzMb9Z6a9292qXA7ElI5E= Received: from mail-qt1-f197.google.com (mail-qt1-f197.google.com [209.85.160.197]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-154-PcaNpfU4NdOhc17bOfpkBA-1; Thu, 20 Feb 2020 11:31:43 -0500 X-MC-Unique: PcaNpfU4NdOhc17bOfpkBA-1 Received: by mail-qt1-f197.google.com with SMTP id x8so2956873qtq.14 for ; Thu, 20 Feb 2020 08:31:43 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=gp1yBY+tfz3ASfvSkHX3QDXKz8JE+vKM1ZqbokypNuk=; b=jE1K5A93Loddn4WcRNsHXcaeThTI4Tpy9FPuxioCHF4fAZsHznfrBxFYqnWwd60y+g 7+w2YigP6IW+KoQdjr9Ro6qXH2RxuRYcq+5uisIFoP+0+o+5impUvQnMIwz6D8MrGO7P w74FFwdSiaDN1QwB/gqg6NgZLrqpn0KxsCScSZLTwqwSgHVnQe5xXwFCzlJ+RVklY+B2 EhWspFKEKS1BOfh4RXlTajOxf8GvTOqBgVs7AVP7g5ViTljmhA0tVgekAQOAu+ZF8R+b CU/eeQAGlhOTKvoQBXt15gZrGM20XRPjMZEmhM9XBG+5/VG2Mt34U8fpju79mi5IGZsW zajw== X-Gm-Message-State: APjAAAXUblmZauBQZJsut4qLvO5sTBnRR5Pl0KTUUoPl8weLnsSIKW1+ 6cnLw3rE6Nel2lbfhPsrpLArdmj1GYJjk2uOfmgW93duHRQcACvHlm3a6AwK6qJXnuzr7tXLo83 VvlGpqXFGqb1S7YvGXuaQPxcV X-Received: by 2002:a0c:f8c6:: with SMTP id h6mr26863086qvo.239.1582216303200; Thu, 20 Feb 2020 08:31:43 -0800 (PST) X-Google-Smtp-Source: APXvYqyLQom3vQH0usWmFRQsDeOtxC8SZvueF6+wF3aikKMPHtAIMojm8cCOEtP1dTBilcK23E+sjQ== X-Received: by 2002:a0c:f8c6:: with SMTP id h6mr26863069qvo.239.1582216302958; Thu, 20 Feb 2020 08:31:42 -0800 (PST) Received: from xz-x1.redhat.com ([104.156.64.75]) by smtp.gmail.com with ESMTPSA id l19sm42366qkl.3.2020.02.20.08.31.41 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 20 Feb 2020 08:31:42 -0800 (PST) From: Peter Xu To: linux-mm@kvack.org, linux-kernel@vger.kernel.org Cc: Brian Geffon , Pavel Emelyanov , Mike Kravetz , David Hildenbrand , peterx@redhat.com, Martin Cracauer , Andrea Arcangeli , Mel Gorman , Bobby Powers , Mike Rapoport , "Kirill A . Shutemov" , Maya Gokhale , Johannes Weiner , Marty McFadden , Denis Plotnikov , Hugh Dickins , "Dr . David Alan Gilbert" , Jerome Glisse Subject: [PATCH v6 15/19] userfaultfd: wp: don't wake up when doing write protect Date: Thu, 20 Feb 2020 11:31:08 -0500 Message-Id: <20200220163112.11409-16-peterx@redhat.com> X-Mailer: git-send-email 2.24.1 In-Reply-To: <20200220163112.11409-1-peterx@redhat.com> References: <20200220163112.11409-1-peterx@redhat.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org It does not make sense to try to wake up any waiting thread when we're write-protecting a memory region. Only wake up when resolving a write protected page fault. Reviewed-by: Mike Rapoport Signed-off-by: Peter Xu --- fs/userfaultfd.c | 13 ++++++++----- 1 file changed, 8 insertions(+), 5 deletions(-) diff --git a/fs/userfaultfd.c b/fs/userfaultfd.c index 59e9e399fddb..6e878d23547c 100644 --- a/fs/userfaultfd.c +++ b/fs/userfaultfd.c @@ -1812,6 +1812,7 @@ static int userfaultfd_writeprotect(struct userfaultfd_ctx *ctx, struct uffdio_writeprotect uffdio_wp; struct uffdio_writeprotect __user *user_uffdio_wp; struct userfaultfd_wake_range range; + bool mode_wp, mode_dontwake; if (READ_ONCE(ctx->mmap_changing)) return -EAGAIN; @@ -1830,18 +1831,20 @@ static int userfaultfd_writeprotect(struct userfaultfd_ctx *ctx, if (uffdio_wp.mode & ~(UFFDIO_WRITEPROTECT_MODE_DONTWAKE | UFFDIO_WRITEPROTECT_MODE_WP)) return -EINVAL; - if ((uffdio_wp.mode & UFFDIO_WRITEPROTECT_MODE_WP) && - (uffdio_wp.mode & UFFDIO_WRITEPROTECT_MODE_DONTWAKE)) + + mode_wp = uffdio_wp.mode & UFFDIO_WRITEPROTECT_MODE_WP; + mode_dontwake = uffdio_wp.mode & UFFDIO_WRITEPROTECT_MODE_DONTWAKE; + + if (mode_wp && mode_dontwake) return -EINVAL; ret = mwriteprotect_range(ctx->mm, uffdio_wp.range.start, - uffdio_wp.range.len, uffdio_wp.mode & - UFFDIO_WRITEPROTECT_MODE_WP, + uffdio_wp.range.len, mode_wp, &ctx->mmap_changing); if (ret) return ret; - if (!(uffdio_wp.mode & UFFDIO_WRITEPROTECT_MODE_DONTWAKE)) { + if (!mode_wp && !mode_dontwake) { range.start = uffdio_wp.range.start; range.len = uffdio_wp.range.len; wake_userfault(ctx, &range); -- 2.24.1