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=-17.6 required=3.0 tests=DKIMWL_WL_MED,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_GIT,USER_IN_DEF_DKIM_WL 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 83627C5B57D for ; Wed, 3 Jul 2019 00:37:23 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 56042218A5 for ; Wed, 3 Jul 2019 00:37:23 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="qKiWSMCy" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727114AbfGCAhV (ORCPT ); Tue, 2 Jul 2019 20:37:21 -0400 Received: from mail-oi1-f202.google.com ([209.85.167.202]:34973 "EHLO mail-oi1-f202.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727025AbfGCAhV (ORCPT ); Tue, 2 Jul 2019 20:37:21 -0400 Received: by mail-oi1-f202.google.com with SMTP id i132so327885oif.2 for ; Tue, 02 Jul 2019 17:37:21 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=date:message-id:mime-version:subject:from:to:cc; bh=MklO/nCO3vTONhpU2/Xc+PDQxZ8geoXuw22CpQ4sZO8=; b=qKiWSMCySfNKdrYjXhmrf6cfPbbz+oWEXvqnz1cpm0Z7vknJMNKnxJ+lQlVEm0E3hG RB9MJVn2xxeW/3haHy4B43l9sOPJSz9tekq/KPZSWh1be1FAzolI0qebmS2oJK4IXslI E1L/+HV1EWoRH9KnyHD4xeVzCWprAVojb7MrOxidOZ8BROzux7QmYFoYmx/+uLK1SX2D 58G/T2wFKuZgk4DoXdfPCyK4TGp42G+xC48rMy1I7hzqFMoEyzh+cb+CIkDARyYfI1h1 T5urZELFI4Fv+PnARlvjBvJrNSrFCRqIrsztsO3BARX88+dqkQv2cu5IH+wuoQj1vloo wACA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:message-id:mime-version:subject:from:to:cc; bh=MklO/nCO3vTONhpU2/Xc+PDQxZ8geoXuw22CpQ4sZO8=; b=gR57aEpcHA4yPef3ZsbLIBgXeGb+Jl65Peur8ClH+IK0AMZVGC6Rz3yp092Uhm9mXr 33IdlWu5Kdsz/jvbOOvMB/l19nDFv5+6H6TRHOtPf8YbVkWpVite2d5WbC5lK0yqnUqM brITJGZfCwNR1hhwaxEySuDechTOvIMh8yfwAmyGuleOVgKS36Hux9f/a9Q96sWoe0rf W4CEsshHre9S5HslQV45RJaUkz2bBoYMrg1JUBtgQgOcMxvnYiu3gq8wQJVbpN6zDK7M BXQZtBeqLHNppBx0m69PVTYtF1+VIG1RYFtAsUDaHm4UytOPZIWqfSrlnbi01i52gWrr XEJQ== X-Gm-Message-State: APjAAAWSc3vZdqB20OCZQ/qKz09yNTm2KIt4f+1YE0hhJ2rkER7aAnBP dPawm9UMGXc3YCqiMLM7rmcQ4JE96tLhSzbm X-Google-Smtp-Source: APXvYqwxWC5LdWcl2/XKPgh1zut3SpHgJ3FIJ714nB1MgOY6lhh76l/rN5P/M8Kednj/Tx9T/ZAwDQyC84jyWjts X-Received: by 2002:a65:6106:: with SMTP id z6mr20033643pgu.250.1562110550143; Tue, 02 Jul 2019 16:35:50 -0700 (PDT) Date: Tue, 2 Jul 2019 16:35:38 -0700 Message-Id: <20190702233538.52793-1-henryburns@google.com> Mime-Version: 1.0 X-Mailer: git-send-email 2.22.0.410.gd8fdbe21b5-goog Subject: [PATCH v3] mm/z3fold.c: Lock z3fold page before __SetPageMovable() From: Henry Burns To: Vitaly Wool , Andrew Morton Cc: Vitaly Vul , Mike Rapoport , Xidong Wang , Shakeel Butt , Jonathan Adams , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Henry Burns , David Rientjes , stable@vger.kernel.org Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Following zsmalloc.c's example we call trylock_page() and unlock_page(). Also make z3fold_page_migrate() assert that newpage is passed in locked, as per the documentation. Link: http://lkml.kernel.org/r/20190702005122.41036-1-henryburns@google.com Signed-off-by: Henry Burns Suggested-by: Vitaly Wool Acked-by: Vitaly Wool Acked-by: David Rientjes Cc: Shakeel Butt Cc: Vitaly Vul Cc: Mike Rapoport Cc: Xidong Wang Cc: Jonathan Adams Cc: Signed-off-by: Andrew Morton --- Changelog since v2: - Removed the WARN_ON entirely, as it is an expected code path. Changelog since v1: - Added an if statement around WARN_ON(trylock_page(page)) to avoid unlocking a page locked by a someone else. mm/z3fold.c | 12 +++++++++++- 1 file changed, 11 insertions(+), 1 deletion(-) diff --git a/mm/z3fold.c b/mm/z3fold.c index e174d1549734..eeb3fe7f5ca3 100644 --- a/mm/z3fold.c +++ b/mm/z3fold.c @@ -918,7 +918,16 @@ static int z3fold_alloc(struct z3fold_pool *pool, size_t size, gfp_t gfp, set_bit(PAGE_HEADLESS, &page->private); goto headless; } - __SetPageMovable(page, pool->inode->i_mapping); + if (can_sleep) { + lock_page(page); + __SetPageMovable(page, pool->inode->i_mapping); + unlock_page(page); + } else { + if (!trylock_page(page)) { + __SetPageMovable(page, pool->inode->i_mapping); + unlock_page(page); + } + } z3fold_page_lock(zhdr); found: @@ -1325,6 +1334,7 @@ static int z3fold_page_migrate(struct address_space *mapping, struct page *newpa VM_BUG_ON_PAGE(!PageMovable(page), page); VM_BUG_ON_PAGE(!PageIsolated(page), page); + VM_BUG_ON_PAGE(!PageLocked(newpage), newpage); zhdr = page_address(page); pool = zhdr_to_pool(zhdr); -- 2.22.0.410.gd8fdbe21b5-goog