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=-7.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED 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 F3A11C43387 for ; Mon, 7 Jan 2019 13:50:44 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C4C212147C for ; Mon, 7 Jan 2019 13:50:44 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728638AbfAGNuo (ORCPT ); Mon, 7 Jan 2019 08:50:44 -0500 Received: from szxga04-in.huawei.com ([45.249.212.190]:17089 "EHLO huawei.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1727943AbfAGNul (ORCPT ); Mon, 7 Jan 2019 08:50:41 -0500 Received: from DGGEMS403-HUB.china.huawei.com (unknown [172.30.72.59]) by Forcepoint Email with ESMTP id 6B658FB66F1F160458EC; Mon, 7 Jan 2019 21:50:37 +0800 (CST) Received: from [127.0.0.1] (10.202.226.43) by DGGEMS403-HUB.china.huawei.com (10.3.19.203) with Microsoft SMTP Server id 14.3.408.0; Mon, 7 Jan 2019 21:50:35 +0800 Subject: Re: [PATCH] scsi/mvsas/mv_init.c: Use dma_zalloc_coherent To: Souptick Joarder References: <5bf56248.1c69fb81.21a6e.5a72@mx.google.com> <8af8ef0a-add1-1010-6ef3-7e5c6ff51aa9@huawei.com> CC: Sabyasachi Gupta , James Bottomley , "Martin K. Petersen" , Johannes Thumshirn , linux-scsi , , Brajeswar Ghosh From: John Garry Message-ID: <1e3d2653-67b5-07a2-37c3-d3e39532cbcb@huawei.com> Date: Mon, 7 Jan 2019 13:50:29 +0000 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:45.0) Gecko/20100101 Thunderbird/45.3.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset="utf-8"; format=flowed Content-Transfer-Encoding: 7bit X-Originating-IP: [10.202.226.43] X-CFilter-Loop: Reflected Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 04/01/2019 19:49, Souptick Joarder wrote: > On Fri, Jan 4, 2019 at 9:34 PM John Garry wrote: >> >> On 04/01/2019 15:11, Sabyasachi Gupta wrote: >>> On Fri, Jan 4, 2019 at 6:43 PM John Garry wrote: >>>> >>>> On 04/01/2019 12:48, Sabyasachi Gupta wrote: >>>>> On Wed, Dec 19, 2018 at 6:49 PM Sabyasachi Gupta >>>>> wrote: >>>>>> >>>>>> On Sat, Dec 1, 2018 at 6:40 PM Sabyasachi Gupta >>>>>> wrote: >>>>>>> >>>>>>> On Wed, Nov 21, 2018 at 7:18 PM Sabyasachi Gupta >>>>>>> wrote: >>>>>>>> >>>>>>>> Replace dma_alloc_coherent + memset with dma_zalloc_coherent >>>>>>>> >>>> >>>> If you're going to make this change, then how about change these to the >>>> managed version, so that we can avoid the explicit free'ing at driver >>>> removal? >>> >>> I can't get it >> >> Please see dmam_alloc_coherent(). You can set __GFP_ZERO in the gfp >> argument to memset(0). > > and dma_zalloc_coherent() did the same. So both are same right ? No ? > Firstly I would to say that I am not so keen on changes like this since (I assume) it will not be tested at all. However, having said that, the reason to use dmam_alloc_coherent() is that you can also drop the dma_free_coherent() in mvs_free(). But changes like that would actually require some code analysis effort... John >> >> I would say that this is a more useful change. >> >>> >>>> >>>>>>>> Signed-off-by: Sabyasachi Gupta >>>>>>> >>>>>>> Any comment on this patch? >>>>>> >>>>>> Any comment on this patch? >>>>> >>>>> Any comment on this patch? >>>>> >>>>>> >>>>>>> >>>>>>>> --- >>>>>>>> drivers/scsi/mvsas/mv_init.c | 12 ++++-------- >>>>>>>> 1 file changed, 4 insertions(+), 8 deletions(-) >>>>>>>> >>>>>>>> diff --git a/drivers/scsi/mvsas/mv_init.c b/drivers/scsi/mvsas/mv_init.c >>>>>>>> index 3ac3437..495bddb 100644 >>>>>>>> --- a/drivers/scsi/mvsas/mv_init.c >>>>>>>> +++ b/drivers/scsi/mvsas/mv_init.c >>>>>>>> @@ -253,33 +253,29 @@ static int mvs_alloc(struct mvs_info *mvi, struct Scsi_Host *shost) >>>>>>>> /* >>>>>>>> * alloc and init our DMA areas >>>>>>>> */ >>>>>>>> - mvi->tx = dma_alloc_coherent(mvi->dev, >>>>>>>> + mvi->tx = dma_zalloc_coherent(mvi->dev, >>>>>>>> sizeof(*mvi->tx) * MVS_CHIP_SLOT_SZ, >>>>>>>> &mvi->tx_dma, GFP_KERNEL); >>>> >>>> I'm guessing that this does not pass checkpatch with --strict option. >>>> >>>> Thanks, >>>> John >>> >>> I have not not checked with --strict option >> >> It may warn that you're not maintaining alignment. >> >>> >>>> >>>>>>>> if (!mvi->tx) >>>>>>>> goto err_out; >>>>>>>> - memset(mvi->tx, 0, sizeof(*mvi->tx) * MVS_CHIP_SLOT_SZ); >>>>>>>> - mvi->rx_fis = dma_alloc_coherent(mvi->dev, MVS_RX_FISL_SZ, >>>>>>>> + mvi->rx_fis = dma_zalloc_coherent(mvi->dev, MVS_RX_FISL_SZ, >>>>>>>> &mvi->rx_fis_dma, GFP_KERNEL); >>>>>>>> if (!mvi->rx_fis) >>>>>>>> goto err_out; >>>>>>>> - memset(mvi->rx_fis, 0, MVS_RX_FISL_SZ); >>>>>>>> >>>>>>>> - mvi->rx = dma_alloc_coherent(mvi->dev, >>>>>>>> + mvi->rx = dma_zalloc_coherent(mvi->dev, >>>>>>>> sizeof(*mvi->rx) * (MVS_RX_RING_SZ + 1), >>>>>>>> &mvi->rx_dma, GFP_KERNEL); >>>>>>>> if (!mvi->rx) >>>>>>>> goto err_out; >>>>>>>> - memset(mvi->rx, 0, sizeof(*mvi->rx) * (MVS_RX_RING_SZ + 1)); >>>>>>>> mvi->rx[0] = cpu_to_le32(0xfff); >>>>>>>> mvi->rx_cons = 0xfff; >>>>>>>> >>>>>>>> - mvi->slot = dma_alloc_coherent(mvi->dev, >>>>>>>> + mvi->slot = dma_zalloc_coherent(mvi->dev, >>>>>>>> sizeof(*mvi->slot) * slot_nr, >>>>>>>> &mvi->slot_dma, GFP_KERNEL); >>>>>>>> if (!mvi->slot) >>>>>>>> goto err_out; >>>>>>>> - memset(mvi->slot, 0, sizeof(*mvi->slot) * slot_nr); >>>>>>>> >>>>>>>> mvi->bulk_buffer = dma_alloc_coherent(mvi->dev, >>>>>>>> TRASH_BUCKET_SIZE, >>>>>>>> -- >>>>>>>> 2.7.4 >>>>>>>> >>>>> >>>>> . >>>>> >>>> >>>> >>> >>> . >>> >> >> > > . >