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=-17.5 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 2BBCBC636CB for ; Sun, 18 Jul 2021 10:43:01 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0A78A61186 for ; Sun, 18 Jul 2021 10:43:01 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232663AbhGRKp4 (ORCPT ); Sun, 18 Jul 2021 06:45:56 -0400 Received: from mail.kernel.org ([198.145.29.99]:58810 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230461AbhGRKpz (ORCPT ); Sun, 18 Jul 2021 06:45:55 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 7CCB96113D; Sun, 18 Jul 2021 10:42:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1626604977; bh=XHYiGCB7BFoBQaLsMUEaVYK3yF6fmDUK9zms1YeaP1E=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=b4KB43F8+DVXSCb+y+cuxXnAE/ZvLCHi7u05iaNnXxO2O8segAdTOmjjGDO7H+Qxg dWd4OuJ4/SYKV8jQuBJJQGaocUE+2a4vHx81YhapryQBNZTzBOWeOcF0dKVOLvT2nq kyPk8xLbhA51hVsulPyzGjBE+btl8gZH0UsHYbPt5EWNKxVbYUsb0tdB6ijeqOykaJ tcucoIAYt1BpeICUV1ZeKOWcuHlkeuHOpAxkgUAJypQ6rC2dzsnu9ZxVey6zQUh/9Y wN0dczatn6FdoD53LkHFDlFVgvaN6HhoI8nx5VeGWapG+T0thB5NHE+xvbImGyyhrh yigZyZRtxdN6g== Date: Sun, 18 Jul 2021 13:42:53 +0300 From: Leon Romanovsky To: Xiyu Yang Cc: Raju Rangoju , "David S. Miller" , Jakub Kicinski , netdev@vger.kernel.org, linux-kernel@vger.kernel.org, yuanxzhang@fudan.edu.cn, Xin Tan Subject: Re: [PATCH] cxgb3: Convert from atomic_t to refcount_t on l2t_entry->refcnt Message-ID: References: <1626516975-42566-1-git-send-email-xiyuyang19@fudan.edu.cn> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1626516975-42566-1-git-send-email-xiyuyang19@fudan.edu.cn> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, Jul 17, 2021 at 06:16:15PM +0800, Xiyu Yang wrote: > refcount_t type and corresponding API can protect refcounters from > accidental underflow and overflow and further use-after-free situations. > > Signed-off-by: Xiyu Yang > Signed-off-by: Xin Tan > --- > drivers/net/ethernet/chelsio/cxgb3/l2t.c | 15 ++++++++------- > drivers/net/ethernet/chelsio/cxgb3/l2t.h | 10 +++++++--- > 2 files changed, 15 insertions(+), 10 deletions(-) > > diff --git a/drivers/net/ethernet/chelsio/cxgb3/l2t.c b/drivers/net/ethernet/chelsio/cxgb3/l2t.c > index 9749d1239f58..0f2a47bc20d8 100644 > --- a/drivers/net/ethernet/chelsio/cxgb3/l2t.c > +++ b/drivers/net/ethernet/chelsio/cxgb3/l2t.c > @@ -225,10 +225,11 @@ static struct l2t_entry *alloc_l2e(struct l2t_data *d) > > /* there's definitely a free entry */ > for (e = d->rover, end = &d->l2tab[d->nentries]; e != end; ++e) > - if (atomic_read(&e->refcnt) == 0) > + if (refcount_read(&e->refcnt) == 0) All those atomic_t to refcount_t patches can't be right, refcount_t can't be 0. Thanks