Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
Message-ID: <c2b5dd7c-9aed-e72c-9685-66680885583b@intel.com>
Date:   Tue, 30 May 2023 08:36:43 -0700
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101
 Betterbird/102.11.0
Subject: Re: [PATCH] dmaengine: idxd: No need to clear memory after a
 dma_alloc_coherent() call
To:     Christophe JAILLET <christophe.jaillet@wanadoo.fr>,
        Fenghua Yu <fenghua.yu@intel.com>,
        Vinod Koul <vkoul@kernel.org>
CC:     <linux-kernel@vger.kernel.org>, <kernel-janitors@vger.kernel.org>,
        <dmaengine@vger.kernel.org>
References: <f44be04317387f8936d31d5470963541615f30ef.1685283065.git.christophe.jaillet@wanadoo.fr>
Content-Language: en-US
From:   Dave Jiang <dave.jiang@intel.com>
In-Reply-To: <f44be04317387f8936d31d5470963541615f30ef.1685283065.git.christophe.jaillet@wanadoo.fr>
Content-Type: text/plain; charset="UTF-8"; format=flowed
Content-Transfer-Encoding: 7bit
MIME-Version: 1.0
X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1
X-MS-Exchange-AntiSpam-MessageData-0: =?utf-8?B?ZmlWZGNabW1VNEhkUFBlb0FqNm5BMEtCN0RvWU92OWR0bEUrNUx4SzhpbnBP?=
 =?utf-8?B?M0p4ZWhPTXZ2bnV4dDBQVEx0SFdyclFLZ0pITWkrNFdXSldMd291NVJreWJO?=
 =?utf-8?B?WUFpR0UrU21mSXBlQnV2Mys2Q2xTUDJaaGlGRVk4QlZGNlpVVHR1UGs0eWJw?=
 =?utf-8?B?Q1krK1pFaGJ3YkFPTklvcDdkSHhEYTBEVGh3clpGMWtLWStEem9FbzR0Q0ov?=
 =?utf-8?B?RG9KbWdkUTRya3JwL2Z5dk9ta0VHWWRrUEIyeGlMSjMydjNQUjloMUZ1Njht?=
 =?utf-8?B?UDRIRVEvcFZ3dXpGTGtQZ1l6dVFDY1hTNTdXaGlLREwzL1htUmFhaG1ROGJU?=
 =?utf-8?B?eFpIbnF2RGdEaVBoWjBaV3NTRkNiUzArZkg4S2FTS1N6TzdQQWxSZEgyU05C?=
 =?utf-8?B?dUdPOC9oRDJvblpVRFYwN3VDNmhJK0FtL0doN2x1N1FkMTRUM1VicTFOS2JM?=
 =?utf-8?B?U3JzeWN3bW4zQUhTNjR2UHREMUdqY2dVRVd3Z0o3c0UraXNvcTZLTS9oWldu?=
 =?utf-8?B?YVA2Ni9rb1VXTWcwSzJ0RVYvY2ZpSUdPT0xHZ3hJaDJJZk9qL1I5cXM5SWk2?=
 =?utf-8?B?NlFzZUdsNTArVng3OEs3MmNNaW54K00yVkpEcDJlQTNva3FLRmdteVBaQkRz?=
 =?utf-8?B?SW95TnpmZHpQNHBJV2l5Sk9nK2FBeGhMRk1CNTRNOXZ1N3Z2OVM5dHF6c2M3?=
 =?utf-8?B?Zzk3ZlViR2ZBZ29lOGZxWnlUV0dKTUp4Y0Nsamw0Q1N5QUcwY2JzdU00ZjFQ?=
 =?utf-8?B?Uk1qQVFIamVHSHhVK1JabGJIcENUZzdlZmwzNkw2OFREUWxmbW9hR2s2RnFP?=
 =?utf-8?B?UmhLZ1dLejlqZUo5a2ltcmVIQ09SL3grTllMTlFDbzlHWDFKcHhRS01JOVNH?=
 =?utf-8?B?TitSVGdveUNTRFNhVE5BOVlKK3RLUytzZGttUlFwQTAzTVVJZWpaNi94dDZa?=
 =?utf-8?B?MVhVczN1MUpJa0pVYzA1UGx3dXV4TEgxY1dTb3o3VmR4TEJhc0JOb2lQWDlz?=
 =?utf-8?B?VGFVM2ZaWEgwYWNXbmxWNmV4bC9ISHdWbXM3Q3BDbXRLbFBhRWFnUkdWc2U5?=
 =?utf-8?B?UitleEpXVGJUeTlyNUZDVEtxTURxSVpGbStyOGhGY0p3WGxqa3pjQjhVbHFn?=
 =?utf-8?B?QUV4NUlOaW5pSGFaTmZZa2s1aTRsZnZmWUZiRTlxVHNITlM5Z3FNeGI3ZjdG?=
 =?utf-8?B?bmtxSy9oUjFVNVJ1ajVqREh3dUZxUEFCQjVLeHEzaGx2T3ZielJGZFg4MDVY?=
 =?utf-8?B?UDJvbWY1L0l0aGZSckt1Sm5JVm9tVTNLNEt0K2lsWmV1c1VoZ2FzMWlkUzZz?=
 =?utf-8?B?VGZmTGs2U2dTeFQ1bGYyYkxIQjRCbTFTa0U5Wm5WZjRBeVpocHZiWi9lYkk2?=
 =?utf-8?B?U21hbmVZN01XZ1psZVFDQmJWZEE4NjZOT29xMXFITkw1L2crRnpRRnlMN3Zu?=
 =?utf-8?B?dmdKRUR2anJYN3VlTDZVS2l3enREaWUyZVVUSU4vdk0zaFdrblYwK01KRFhR?=
 =?utf-8?B?ek54UUtrc24xQWdKck9UdkFHakpIMWxaelQ0cWRtWDJIK1c4SmExdlg3Y3Rt?=
 =?utf-8?B?QmZDS1hRYUpES08rVENqMDRzUm5qWThsMGcwZzFDUERJczJiRFc4ZDNpb0hV?=
 =?utf-8?B?M2pFQnZuS2lZcVIvOWs1WjFtTEhPajlzRmxrT1dDTHVSZU1KWm5jL2lvUnM3?=
 =?utf-8?B?ZzI3L08vVHJUUUNoNyttM0lUVjhac2VPdkJzVjZnVHVMLzZDSjd3THZ4S1Ba?=
 =?utf-8?B?SkZZME9hZDVhclJrTDdGSHk4T1p6QWgzdXNwYURkd25zYXNlVGRUV3hRL3ht?=
 =?utf-8?B?eGN0TWdoTlpBc2lMZ3RRQ284alRaNjlMc1I3SVJBSSs3M1kvTnowOW4vakQ2?=
 =?utf-8?B?Tkc0U1VIbWtnTzJBMzVCbmRKK3RJTmxnTXVxSS91Skhkbmg4T1huMGVYNGZX?=
 =?utf-8?B?V3o3bjR2ZFlQOXFVZ3I5UmxTcVJFZVBLUWVpSnFuR01pemZHT1JhdFl5Y1Zj?=
 =?utf-8?B?bENsRUJUVkNyQTV5aldZcDlheWVaLzJ0dFVYTnlEdHFhRXh2N1lCN2thRXNX?=
 =?utf-8?B?OHZtTG9KaEFnTzNWYTJwb3dqK3ZXQnBkbTJWT2FrSHhuclFnbVkrSjV0NTNU?=
 =?utf-8?Q?FNDZ0KMVrq0hTlLhybvSgM6in?=
X-MS-Exchange-CrossTenant-Network-Message-Id: 8924b55a-d066-4df7-44ea-08db6123adcd
X-MS-Exchange-CrossTenant-AuthSource: PH7PR11MB5984.namprd11.prod.outlook.com
X-MS-Exchange-CrossTenant-AuthAs: Internal
X-MS-Exchange-CrossTenant-OriginalArrivalTime: 30 May 2023 15:36:47.4114
 (UTC)
X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted
X-MS-Exchange-CrossTenant-Id: 46c98d88-e344-4ed4-8496-4ed7712e255d
X-MS-Exchange-CrossTenant-MailboxType: HOSTED
X-MS-Exchange-CrossTenant-UserPrincipalName: MYa84G8vCpsNSnB9aTeljs5zwFXCt04LwYUjp+NZbVKxx543Z9NhGvUUI+7mIJvY21qr9lWYCdU6A89ZS+NQ6A==
X-MS-Exchange-Transport-CrossTenantHeadersStamped: SA3PR11MB7433
X-OriginatorOrg: intel.com
X-Spam-Status: No, score=-4.7 required=5.0 tests=BAYES_00,DKIMWL_WL_HIGH,
        DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,NICE_REPLY_A,
        RCVD_IN_DNSWL_MED,RCVD_IN_MSPIKE_H3,RCVD_IN_MSPIKE_WL,SPF_HELO_NONE,
        SPF_NONE,T_SCC_BODY_TEXT_LINE,URIBL_BLOCKED autolearn=ham
        autolearn_force=no version=3.4.6
X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on
        lindbergh.monkeyblade.net
Precedence: bulk
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org


On 5/28/23 07:11, Christophe JAILLET wrote:
> dma_alloc_coherent() already clear the allocated memory, there is no need
> to explicitly call memset().
>
> Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Acked-by: Dave Jiang <dave.jiang@intel.com>
> ---
>   drivers/dma/idxd/device.c | 2 --
>   1 file changed, 2 deletions(-)
>
> diff --git a/drivers/dma/idxd/device.c b/drivers/dma/idxd/device.c
> index 5abbcc61c528..7c74bc60f582 100644
> --- a/drivers/dma/idxd/device.c
> +++ b/drivers/dma/idxd/device.c
> @@ -786,8 +786,6 @@ static int idxd_device_evl_setup(struct idxd_device *idxd)
>   		goto err_alloc;
>   	}
>   
> -	memset(addr, 0, size);
> -
>   	spin_lock(&evl->lock);
>   	evl->log = addr;
>   	evl->dma = dma_addr;