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=-13.3 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_SANE_1 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 BB027C4321A for ; Fri, 28 Jun 2019 09:48:44 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 8B48F205ED for ; Fri, 28 Jun 2019 09:48:44 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=c-s.fr header.i=@c-s.fr header.b="MS3nJFuQ" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726543AbfF1Jsn (ORCPT ); Fri, 28 Jun 2019 05:48:43 -0400 Received: from pegase1.c-s.fr ([93.17.236.30]:6601 "EHLO pegase1.c-s.fr" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726426AbfF1Jsm (ORCPT ); Fri, 28 Jun 2019 05:48:42 -0400 Received: from localhost (mailhub1-int [192.168.12.234]) by localhost (Postfix) with ESMTP id 45ZsQt4qzzz9v0wQ; Fri, 28 Jun 2019 11:48:38 +0200 (CEST) Authentication-Results: localhost; dkim=pass reason="1024-bit key; insecure key" header.d=c-s.fr header.i=@c-s.fr header.b=MS3nJFuQ; dkim-adsp=pass; dkim-atps=neutral X-Virus-Scanned: Debian amavisd-new at c-s.fr Received: from pegase1.c-s.fr ([192.168.12.234]) by localhost (pegase1.c-s.fr [192.168.12.234]) (amavisd-new, port 10024) with ESMTP id pZl8gME9hagL; Fri, 28 Jun 2019 11:48:38 +0200 (CEST) Received: from messagerie.si.c-s.fr (messagerie.si.c-s.fr [192.168.25.192]) by pegase1.c-s.fr (Postfix) with ESMTP id 45ZsQt3hYvz9v0wP; Fri, 28 Jun 2019 11:48:38 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=c-s.fr; s=mail; t=1561715318; bh=WnV7UDb4Snu6Dal6gfhwWBwcbdeIzVY+ODIk60JqE8U=; h=Subject:To:Cc:References:From:Date:In-Reply-To:From; b=MS3nJFuQi4Hf5KytCdDPMJmuQIqksXtUv+pid9Fl/u0KJYekztCou460LJG5gykDi W0Vg4NLAUntrhH3cTTCNfxD8RqTqB2eq1t9hBt3Cvfhtk44yuE1Q/jnMoowZgyadGh e0lyr+rsJsM77xp5aZK7bDQEcJSoyrnZzOb0oqME= Received: from localhost (localhost [127.0.0.1]) by messagerie.si.c-s.fr (Postfix) with ESMTP id 9CEA88B967; Fri, 28 Jun 2019 11:48:39 +0200 (CEST) X-Virus-Scanned: amavisd-new at c-s.fr Received: from messagerie.si.c-s.fr ([127.0.0.1]) by localhost (messagerie.si.c-s.fr [127.0.0.1]) (amavisd-new, port 10023) with ESMTP id pmeNiNUhoS-G; Fri, 28 Jun 2019 11:48:39 +0200 (CEST) Received: from [172.25.230.101] (po15451.idsi0.si.c-s.fr [172.25.230.101]) by messagerie.si.c-s.fr (Postfix) with ESMTP id 19CB48B966; Fri, 28 Jun 2019 11:48:38 +0200 (CEST) Subject: Re: [PATCH v2 27/27] sound: ppc: remove unneeded memset after dma_alloc_coherent To: Fuqian Huang Cc: Rob Herring , alsa-devel@alsa-project.org, linux-kernel@vger.kernel.org, Greg Kroah-Hartman , Jaroslav Kysela , Richard Fontana , Paul Mackerras , Thomas Gleixner , linuxppc-dev@lists.ozlabs.org, Allison Randal References: <20190628025055.16242-1-huangfq.daxian@gmail.com> <83108dee-72f7-e56f-95f6-26162c9a0ccc@c-s.fr> From: Christophe Leroy Message-ID: Date: Fri, 28 Jun 2019 11:48:37 +0200 User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:60.0) Gecko/20100101 Thunderbird/60.7.2 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: fr Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Le 28/06/2019 à 11:11, Fuqian Huang a écrit : > The merge commit log tells (dma-mapping: zero memory returned from > dma_alloc_* and deprecating the dma_zalloc_coherent). > I used this commit just want to say that dma_alloc_coherent has > zeroed the allocated memory. > Sorry for this mistake. > > Maybe this commit 518a2f1925c3("dma-mapping: zero memory returned from > dma_alloc_*") is correct. Yes that looks appropriate. And it confirms it was already done on powerpc, as that patch doesn't include any change in powerpc arch. Christophe > > Christophe Leroy 於 2019年6月28日週五 下午4:59寫道： > >> >> >> >> Le 28/06/2019 à 04:50, Fuqian Huang a écrit : >>> In commit af7ddd8a627c >>> ("Merge tag 'dma-mapping-4.21' of git://git.infradead.org/users/hch/dma-mapping"), >>> dma_alloc_coherent has already zeroed the memory. >>> So memset is not needed. >> >> You are refering to a merge commit, is that correct ? >> >> I can't see anything related in that commit, can you please pinpoint it ? >> >> As far as I can see, on powerpc the memory has always been zeroized >> (since 2005 at least). >> >> Christophe >> >>> >>> Signed-off-by: Fuqian Huang >>> --- >>> sound/ppc/pmac.c | 1 - >>> 1 file changed, 1 deletion(-) >>> >>> diff --git a/sound/ppc/pmac.c b/sound/ppc/pmac.c >>> index 1b11e53f6a62..1ab12f4f8631 100644 >>> --- a/sound/ppc/pmac.c >>> +++ b/sound/ppc/pmac.c >>> @@ -56,7 +56,6 @@ static int snd_pmac_dbdma_alloc(struct snd_pmac *chip, struct pmac_dbdma *rec, i >>> if (rec->space == NULL) >>> return -ENOMEM; >>> rec->size = size; >>> - memset(rec->space, 0, rsize); >>> rec->cmds = (void __iomem *)DBDMA_ALIGN(rec->space); >>> rec->addr = rec->dma_base + (unsigned long)((char *)rec->cmds - (char *)rec->space); >>> >>>