Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:18 as permitted sender) client-ip=2620:137:e000::1:18;
Message-ID: <adb222bd-cbd4-eab5-78d6-4fa803e20875@nvidia.com>
Date:   Wed, 13 Apr 2022 02:21:47 +0530
User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:91.0) Gecko/20100101
 Thunderbird/91.6.2
Subject: Re: [PATCH 31/34] vfio/mdev: Remove mdev_parent_ops dev_attr_groups
Content-Language: en-US
To:     Christoph Hellwig <hch@lst.de>,
        Jani Nikula <jani.nikula@linux.intel.com>,
        Joonas Lahtinen <joonas.lahtinen@linux.intel.com>,
        Rodrigo Vivi <rodrigo.vivi@intel.com>,
        Zhenyu Wang <zhenyuw@linux.intel.com>,
        Zhi Wang <zhi.a.wang@intel.com>
Cc:     Jason Gunthorpe <jgg@nvidia.com>, intel-gfx@lists.freedesktop.org,
        intel-gvt-dev@lists.freedesktop.org,
        dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org
References: <20220411141403.86980-1-hch@lst.de>
 <20220411141403.86980-32-hch@lst.de>
From:   Kirti Wankhede <kwankhede@nvidia.com>
In-Reply-To: <20220411141403.86980-32-hch@lst.de>
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?YUx3V1drNGJxOUkxSVFtMVpxck15SEZmaVk1c01CUFNEMDh1RDdWWDlKcUt3?=
 =?utf-8?B?ZDFOdFdMd0J5eUtNRFhOM25ONHc2eG51KzZENzBwT2dnYmxXWVQ2VzFpb0Jv?=
 =?utf-8?B?b3JTMTRPSEJrTEpQa2NZU2pCODkyOHRBLzJ0bHdVdUh3VlRmdlVJbjZjQ1Fp?=
 =?utf-8?B?QmxhZnBqemF0eWJPNXl4U0NIVUFJM2s0ZCsza21Sb0dFYkcrM3VHUUdOWjBn?=
 =?utf-8?B?eS9oamU3SmI2K29vMjNNT0ZBZytOSUI2UVVZU1dMRHIwL1dOQXpBRnJiOStv?=
 =?utf-8?B?bkpzWXZOMTNlWnNGalRjSHNtanpZOWhkbkcvRkxIVHJaazNhT2NZZGVUZlBM?=
 =?utf-8?B?YkdDdkFVMzFaaW1sb0xZOVZRWE54SVJjMS9BTi81ZGtRYklmWmozcVBHZC96?=
 =?utf-8?B?aDNGbG9aUUY3MWpsclNWelZCQkhHSjR1VVgyalpxTlRoUkhONlZXVVMrbUlS?=
 =?utf-8?B?ZEdyN3ExVU9qK0JQUi9zU2tJaU14ZGw3bWZ2R3BCWnRCc2JoeFhpeHU4dTMv?=
 =?utf-8?B?MDNibWV2VVgzVTJIdFY4RHF0Y2diU3VHRnlVNGRBTHdyamZESTFqSzRmYjFa?=
 =?utf-8?B?cXZtZUpoRU9RSm9MV01nbDVHck1HTlJQR0tHcnQvU2dsTmpTemNQcmFTTFJk?=
 =?utf-8?B?NXlGOVUvZkFIQ1lKeVpUUjBTUURsQnJGOWwrYkhIM1ZvVytUQUxqOGs5c2V5?=
 =?utf-8?B?NG9nR0VsakY2dFhxY0tWTk1TSzI5REg1bEtFT01MWWp2aXplSmo3Y3FaSmhS?=
 =?utf-8?B?M2V3M29nK1VHOHVMa05NWjNOV1ZUMWxvTFNaRUR1dXVqVlN6V1RGbmdBV2ds?=
 =?utf-8?B?SkRRRlU2ZnhkVlFLT0I1Q1dVdDl3ZnI2N1hQbE9MKzNEWTQ0UHJVWmxQNzVz?=
 =?utf-8?B?dm8xd0tzRUtDUUt5a01xQ09vS0IrMlRnbXF0ZnlJM0ExMDhZaFZaMG5sQStP?=
 =?utf-8?B?dlVFRDBpeUpXRFI5VG1UaTBXMlFLQ1M1TUU5T1NRV1c2Nkt2d2FzSTZMRXlR?=
 =?utf-8?B?MFl6WUlJQ0p5eDNhdVl3VW4xVGlNeHQzbTVEM1pldjV2djF4Qmx3c2x2eTlv?=
 =?utf-8?B?QWhQSEdjSDlFYjYrRzdOMEh5WFhJeGduU3pYcC9Tb2swSnh1TjdybXZEVEdz?=
 =?utf-8?B?N3htaEpsdEMvRXh5c2UvanBlRThBdk5Ed1M0UFpPSi9YQUFEdklBeXdHaGkz?=
 =?utf-8?B?VWFGT1pFN29ma2pWL0tLOVZibXRHWkV1YW1oSkFWMnpFZC9QVmJ6OFdhQ3hp?=
 =?utf-8?B?Mk5YbUYvWngrS3BFSDFtck5yaE9Rc21NbkhabG8vQ09saHZ5eXFNbWdBMWhP?=
 =?utf-8?B?d0NMaGhpSFR5bDhqSHovV1Y5K0dHYllWbWVTOVd6MlYxUmV5UW04Nzg2d0tm?=
 =?utf-8?B?b2EyTnE3M1JzemhadlhmUnpZMjl6aG1hN2Qrc2JXVTU5ZFl6Y21xL3NWVzk3?=
 =?utf-8?B?M1FibnhBbHp5MGFDMGQyM3h1UzNyYTJsdFJzTlpSdnRxTzZURThSTVhpenNm?=
 =?utf-8?B?SHVKUmpzU29rcXE2VUM5c09EUTVFRU9aTVBOMnhwSDlWVHNLcDBiV0VWZ2d3?=
 =?utf-8?B?N2lXT0RxRDVDeUNCcEdkZkJ5WmRqYUJIOVFGemtGMU9uaXBsMmE1U05Xdy85?=
 =?utf-8?B?UEk2R3dzeWljbDZmekxWbTBvVGlzamRkNGFEbVMwWE0vSTJ3TWtZUWVZTGtC?=
 =?utf-8?B?QW1CM05iSk9Temd1K1BMQTVMTjZsYmt3WW04Z24yRlJRTFJEaXVYTTlkTm9i?=
 =?utf-8?B?SEFRamd6NE1VRzlkNzczUWQ5eFRENDFSZXNJcWNRZnhIM2lXaEFRbFZIa0Fa?=
 =?utf-8?B?UUdoSDluZGhWOXJSc0UvYzY3OUtyZHFHVk1hQ3FkN3NBOTF5Qlk2aVduaU9j?=
 =?utf-8?B?OEFXK3NucHlycktrdzRqNGdMOXo4ZzVlWEx5SmI2ckl0eCtxeG4wd2M5SlBF?=
 =?utf-8?B?WFJ4ODcwSnk1Mk5KOWNFOC85NzRJYWJ6eHdvOFZLRmoxaTJDdWZ2Vlg1WWdG?=
 =?utf-8?B?UFVKQVIvRitWZFlnUjFXeS8yekVJd1BMNXhHVnowcG5JVmxVcDExRVcvU3Mr?=
 =?utf-8?B?cW8wR25aa2tWeWs2REZOM1hDUXhZdk1qeWJlUnJPS2RzQTh0T3RYblkwemJp?=
 =?utf-8?B?cUl3UThvZ1A2NjljQkdQalV5b29SaEVYRUljSkkrb2NKN1MrNk15ZW1KQlBO?=
 =?utf-8?B?RkNLbWpvRzhFemk4aW9Pak1yWXFaUVR1d21RZkNWM0phaDdjY3M5ODRVeWZr?=
 =?utf-8?B?T0dzdTdsa0VHN3VDM1FKbmFjc3FRa0J0L2oyS1JBRGtaYTBxZVRjRjZQbXhF?=
 =?utf-8?B?V0JVbnhGQXEvS09DV3ZWNmtLUFdLUEx3V29URXROQUx3SXUzbXE2dz09?=
X-OriginatorOrg: Nvidia.com
X-MS-Exchange-CrossTenant-Network-Message-Id: df4e8198-8227-44dd-8a5f-08da1cc64b77
X-MS-Exchange-CrossTenant-AuthSource: MN2PR12MB4206.namprd12.prod.outlook.com
X-MS-Exchange-CrossTenant-AuthAs: Internal
X-MS-Exchange-CrossTenant-OriginalArrivalTime: 12 Apr 2022 20:52:02.5180
 (UTC)
X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted
X-MS-Exchange-CrossTenant-Id: 43083d15-7273-40c1-b7db-39efd9ccc17a
X-MS-Exchange-CrossTenant-MailboxType: HOSTED
X-MS-Exchange-CrossTenant-UserPrincipalName: 9roXIkzC4UarfrGXlX6hl/5cJcGEKGDr4JruvM0cplhojrYoIe+Zz5jSrP7PuVI9iPgJcKk4n8szmgqrXLCuvQ==
X-MS-Exchange-Transport-CrossTenantHeadersStamped: MWHPR12MB1679
X-Spam-Status: No, score=-3.1 required=5.0 tests=BAYES_00,DKIMWL_WL_HIGH,
	DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,
	MAILING_LIST_MULTI,NICE_REPLY_A,RDNS_NONE,SPF_HELO_NONE,
	T_SCC_BODY_TEXT_LINE autolearn=unavailable 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 4/11/2022 7:44 PM, Christoph Hellwig wrote:
> From: Jason Gunthorpe <jgg@nvidia.com>
> 
> This is only used by one sample to print a fixed string that is pointless.
> 
> In general, having a device driver attach sysfs attributes to the parent
> is horrific. This should never happen, and always leads to some kind of
> liftime bug as it become very difficult for the sysfs attribute to go back
> to any data owned by the device driver.
> 
> Remove the general mechanism to create this abuse.
> 
> Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
> Signed-off-by: Christoph Hellwig <hch@lst.de>
> ---
>   drivers/vfio/mdev/mdev_sysfs.c | 12 ++----------
>   include/linux/mdev.h           |  2 --
>   samples/vfio-mdev/mtty.c       | 30 +-----------------------------
>   3 files changed, 3 insertions(+), 41 deletions(-)
> 

Update Documentation/driver-api/vfio-mediated-device.rst where mtty 
sample code explained. Tree command output should be updated, i.e remove 
below 2 lines.
         |-- mtty_dev
         |   `-- sample_mtty_dev

Rest looks good to me.

Thanks,
Kirti