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=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_PASS,USER_AGENT_MUTT 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 8FC35C43381 for ; Wed, 20 Mar 2019 07:22:43 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 5DF072184E for ; Wed, 20 Mar 2019 07:22:43 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1553066563; bh=Nfnfhu0c82XqgZzyOrfd03WeTxW95KtMNoYxuCEYNrQ=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=SNFu3bvfxKfm/u8B87m4YXXFxvg7OFEyqG2qXLq8Gnq8ckvdVpUiXspwQhkPgY2mH GVFN8PSx0c2RE1BgOKHg/FUw8PfEv1EIqMQy5CnrIfxe2SvI3RTZSCpXY8hD078eml pX0ltMSdytDnbJvodyS4DHdtgL6Prh9CvthT2wJY= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727411AbfCTHWl (ORCPT ); Wed, 20 Mar 2019 03:22:41 -0400 Received: from mail.kernel.org ([198.145.29.99]:53422 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726303AbfCTHWl (ORCPT ); Wed, 20 Mar 2019 03:22:41 -0400 Received: from localhost (5356596B.cm-6-7b.dynamic.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 7868921841; Wed, 20 Mar 2019 07:22:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1553066561; bh=Nfnfhu0c82XqgZzyOrfd03WeTxW95KtMNoYxuCEYNrQ=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=OJAESGhJYSnjRBJHvpeBnuBTiAAdLdcIapObFQzfpB62nDo/gmSpZcLsoDCjEakqT Ht9hGu0UouIrzs1eIlYUampVbUIyTHZwUrBKOnEi8nvqFHkrz//h07mXlT90rv7gDm Ns3ihKwJPq9fTBHsRJ+VjWb329VuaecCY9Gh/0Aw= Date: Wed, 20 Mar 2019 08:22:37 +0100 From: Greg Kroah-Hartman To: George Hilliard Cc: linux-mips@linux-mips.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2 07/11] staging: mt7621-mmc: Check for nonzero number of scatterlist entries Message-ID: <20190320072237.GC1914@kroah.com> References: <20190319022012.11051-1-thirtythreeforty@gmail.com> <20190319022012.11051-8-thirtythreeforty@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190319022012.11051-8-thirtythreeforty@gmail.com> User-Agent: Mutt/1.11.4 (2019-03-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Mar 18, 2019 at 08:20:08PM -0600, George Hilliard wrote: > The buffer descriptor setup loop is correct only if it is setting up at > least one bd struct. Besides, there is an error somewhere if > dma_map_sg() returns 0. So add a paranoid check for this condition. > > Signed-off-by: George Hilliard > --- > drivers/staging/mt7621-mmc/sd.c | 7 ++++++- > 1 file changed, 6 insertions(+), 1 deletion(-) > > diff --git a/drivers/staging/mt7621-mmc/sd.c b/drivers/staging/mt7621-mmc/sd.c > index c272aa780719..31c5b44bd29f 100644 > --- a/drivers/staging/mt7621-mmc/sd.c > +++ b/drivers/staging/mt7621-mmc/sd.c > @@ -593,7 +593,12 @@ static void msdc_dma_setup(struct msdc_host *host, struct msdc_dma *dma, > struct bd *bd; > u32 j; > > - BUG_ON(sglen > MAX_BD_NUM); /* not support currently */ > + // Shouldn't happen; we configure the mmc host layer > + // based on MAX_BD_NUM: > + BUG_ON(sglen > MAX_BD_NUM); > + // Correct setup below requires at least one bd > + // (and dma_map_sg should not return 0): > + BUG_ON(sglen == 0); Same here, no new BUG_ON(). To quote one kernel developer, "BUG_ON() means that the programmer is lazy" :) thanks, greg k-h