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=-0.6 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,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 EAD0DC0650F for ; Fri, 9 Aug 2019 01:12:17 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C2A292166E for ; Fri, 9 Aug 2019 01:12:17 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="ap3AA5Q7" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2405271AbfHIBMQ (ORCPT ); Thu, 8 Aug 2019 21:12:16 -0400 Received: from mail-ed1-f68.google.com ([209.85.208.68]:36568 "EHLO mail-ed1-f68.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2404550AbfHIBMQ (ORCPT ); Thu, 8 Aug 2019 21:12:16 -0400 Received: by mail-ed1-f68.google.com with SMTP id k21so93084685edq.3; Thu, 08 Aug 2019 18:12:14 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc:content-transfer-encoding; bh=q1VDmvy5H5V/lcQDElMHgpagqDBHRV5q2PlN+0yp058=; b=ap3AA5Q7qTtE00hxn3S74U63HIxZRuOIEAkqJtskyVa1jNpnNvhKUvDrT3dAGsl5SF h2/RDfNHPRr5jvA8f6B8NXM6HB02DfY+BP/8ghY3TDNi1E4A+9px3gb2AWH8EVgw6UWR 5dKfp34zFQ2H1rLuXMNlFRuIVPEVt1gWvaRQdkB+rmgNXZPrMxnMrkunvkhKFoqjPcCv Dwrzw1Kt5tlCv0D2XXpTb9ueZanzUxnqkS1xdp9MK3eHxRebHwIBUF6xH07LUxddrU32 95wwhu60FOS1kgOLv3zM+npKW+J94/3fxc84boCfaA3Y2puUH5U6GxfSjl1rwe5Hrjq4 iBEA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc:content-transfer-encoding; bh=q1VDmvy5H5V/lcQDElMHgpagqDBHRV5q2PlN+0yp058=; b=ZXAZxqasuxJOQGf/QK5MMecDd4sGl44k0D1SnQkInTITjCcsETm6CaBsltFwyEVzi7 dzEoQFpPl1wpYIAD2NalB5LeUPSzBqEJax8WqXWMwgiV77xaCbhlJw3Fa2T8D/iJg+g4 zynFAWxRsh/BRrUdqjFbr0Gc/JevulMDLXwxGlewmSn9ECTFEI+yS457EfIw4NjlX1nM Q/gdKDemYTr+h7xZKs1AjoAuw1/VzHXNnUgV6wW5FtXvdONNtqi8PYdoyaWC14YkahnR o12urW0QQ2ZtKl1V0yc0vryhoU5C3YAL+ssK7s5aBTrj9rvmk2xM2uXedR36VCnvYNLp WC8g== X-Gm-Message-State: APjAAAXubARfIRy+mr0x5ILMsIqYtGBVZJuIAXgJu/hXFMyJAjXYOLUa +kAIZQQnxcAw8OTVtgNurAIKG3lbmVl6AdvCFQE= X-Google-Smtp-Source: APXvYqw72mDmwWU01nhdnAQXUm1rWO+j4MknD7wIqU6RymBJZboowbBNIAROGI7j1bBlzLXNIgbxAtgfJJR0skLrINI= X-Received: by 2002:a17:906:7cd6:: with SMTP id h22mr16154601ejp.254.1565313134395; Thu, 08 Aug 2019 18:12:14 -0700 (PDT) MIME-Version: 1.0 References: <20190808131100.24751-1-hslester96@gmail.com> <20190808133510.tre6twn764pv3e7m@Air-de-Roger> In-Reply-To: <20190808133510.tre6twn764pv3e7m@Air-de-Roger> From: Chuhong Yuan Date: Fri, 9 Aug 2019 09:12:04 +0800 Message-ID: Subject: Re: [PATCH 3/3] xen/blkback: Use refcount_t for refcount To: =?UTF-8?Q?Roger_Pau_Monn=C3=A9?= Cc: Konrad Rzeszutek Wilk , Jens Axboe , xen-devel@lists.xenproject.org, linux-block@vger.kernel.org, LKML Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Aug 8, 2019 at 9:35 PM Roger Pau Monn=C3=A9 = wrote: > > On Thu, Aug 08, 2019 at 09:11:00PM +0800, Chuhong Yuan wrote: > > Reference counters are preferred to use refcount_t instead of > > atomic_t. > > This is because the implementation of refcount_t can prevent > > overflows and detect possible use-after-free. > > So convert atomic_t ref counters to refcount_t. > > Thanks! > > I think there are more reference counters in blkback than > the one you fixed. There's also an inflight field in xen_blkif_ring, > and a pendcnt in pending_req which look like possible candidates to > switch to use refcount_t, have you looked into switching those two > also? > I will switch those two in next version. > Roger.