Received-SPF: pass (google.com: domain of linux-kernel+bounces-57955-linux.lists.archive=gmail.com@vger.kernel.org designates 139.178.88.99 as permitted sender) client-ip=139.178.88.99;
From: Ankit Agrawal <ankita@nvidia.com>
To: "Tian, Kevin" <kevin.tian@intel.com>, Alex Williamson
	<alex.williamson@redhat.com>, Zhi Wang <zhi.wang.linux@gmail.com>
CC: Jason Gunthorpe <jgg@nvidia.com>, Yishai Hadas <yishaih@nvidia.com>,
	"mst@redhat.com" <mst@redhat.com>, "shameerali.kolothum.thodi@huawei.com"
	<shameerali.kolothum.thodi@huawei.com>, "clg@redhat.com" <clg@redhat.com>,
	"oleksandr@natalenko.name" <oleksandr@natalenko.name>, "K V P, Satyanarayana"
	<satyanarayana.k.v.p@intel.com>, "eric.auger@redhat.com"
	<eric.auger@redhat.com>, "brett.creeley@amd.com" <brett.creeley@amd.com>,
	"horms@kernel.org" <horms@kernel.org>, Rahul Rameshbabu
	<rrameshbabu@nvidia.com>, Aniket Agashe <aniketa@nvidia.com>, Neo Jia
	<cjia@nvidia.com>, Kirti Wankhede <kwankhede@nvidia.com>, "Tarun Gupta
 (SW-GPU)" <targupta@nvidia.com>, Vikram Sethi <vsethi@nvidia.com>, Andy
 Currid <acurrid@nvidia.com>, Alistair Popple <apopple@nvidia.com>, John
 Hubbard <jhubbard@nvidia.com>, Dan Williams <danw@nvidia.com>, "Anuj Aggarwal
 (SW-GPU)" <anuaggarwal@nvidia.com>, Matt Ochs <mochs@nvidia.com>,
	"kvm@vger.kernel.org" <kvm@vger.kernel.org>, "linux-kernel@vger.kernel.org"
	<linux-kernel@vger.kernel.org>, "virtualization@lists.linux-foundation.org"
	<virtualization@lists.linux-foundation.org>
Subject: Re: [PATCH v17 3/3] vfio/nvgrace-gpu: Add vfio pci variant module for
 grace hopper
Thread-Topic: [PATCH v17 3/3] vfio/nvgrace-gpu: Add vfio pci variant module
 for grace hopper
Thread-Index: AQHaWIdUHF93rAkYa0SGXKd0AMy8rLD/eesAgAAPggCAAHxaWIAACBUAgABAhJ8=
Date: Thu, 8 Feb 2024 11:13:45 +0000
Message-ID:
 <SA1PR12MB7199F11211952B27803D7194B0442@SA1PR12MB7199.namprd12.prod.outlook.com>
References: <20240205230123.18981-1-ankita@nvidia.com>
	<20240205230123.18981-4-ankita@nvidia.com>
	<20240208003210.000078ba.zhi.wang.linux@gmail.com>
 <20240207162740.1d713cf0.alex.williamson@redhat.com>
 <SA1PR12MB7199A9470EC2562C5BCC2FAFB0442@SA1PR12MB7199.namprd12.prod.outlook.com>
 <BN9PR11MB527640ADE99D92210977E7CA8C442@BN9PR11MB5276.namprd11.prod.outlook.com>
In-Reply-To:
 <BN9PR11MB527640ADE99D92210977E7CA8C442@BN9PR11MB5276.namprd11.prod.outlook.com>
Accept-Language: en-US
Content-Language: en-US
msip_labels:
authentication-results: dkim=none (message not signed)
 header.d=none;dmarc=none action=none header.from=nvidia.com;
x-ms-publictraffictype: Email
x-ms-traffictypediagnostic: SA1PR12MB7199:EE_|DM6PR12MB4943:EE_
x-ms-office365-filtering-correlation-id: fcb854af-e06d-4a06-0195-08dc289703f0
x-ms-exchange-senderadcheck: 1
x-ms-exchange-antispam-relay: 0
x-microsoft-antispam: BCL:0;
x-microsoft-antispam-message-info:
 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
x-forefront-antispam-report:
 CIP:255.255.255.255;CTRY:;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:SA1PR12MB7199.namprd12.prod.outlook.com;PTR:;CAT:NONE;SFS:(13230031)(346002)(376002)(136003)(39860400002)(366004)(396003)(230922051799003)(1800799012)(186009)(451199024)(64100799003)(71200400001)(26005)(41300700001)(55016003)(54906003)(38100700002)(38070700009)(316002)(7696005)(9686003)(122000001)(478600001)(6506007)(8936002)(64756008)(91956017)(7416002)(2906002)(33656002)(5660300002)(66476007)(66556008)(66946007)(86362001)(110136005)(8676002)(76116006)(4326008)(4744005)(52536014)(66446008);DIR:OUT;SFP:1101;
x-ms-exchange-antispam-messagedata-chunkcount: 1
x-ms-exchange-antispam-messagedata-0:
 =?iso-8859-1?Q?uzoB5o/jGIcfQymgz67pxQVh7/WBmDU3KixdxvFtjS9XGyhhAtbac2UrTc?=
 =?iso-8859-1?Q?laa2rJqaZRpTfumEg5hminmUZAllK5P3LruDdruzvXu/6ldbX7/dQ7XPBj?=
 =?iso-8859-1?Q?gQ2aEGWEQA+HuqHrXAwGVF6HnEFbDK0ZAr6J4r8krTTuLVEOtK56y2ljG/?=
 =?iso-8859-1?Q?GbaQJcVoxR8AXlM2DIeA5qnhdloOvFT6nIgoCSPi/p/ly1TzZ8VC9u22b+?=
 =?iso-8859-1?Q?bHZODGv0V9weqT+Z+IZKtlV81MwZjP7dC98zzdMplfJa0z91BjP3ZCBzHA?=
 =?iso-8859-1?Q?6oypmudBJzpMVfxA+eMQy67oqcAWb6zK7JEKXVjxuzFaBX6IisVJPJfyC4?=
 =?iso-8859-1?Q?+jly1+IHp5H2qZZ6LdGZh1XjHRujSB1TjoznAoToSRDKPra0SnncnqFf3A?=
 =?iso-8859-1?Q?/p8TJHFBZwpoq2PcEDQWGEfsd7DgvrgNpydoSA9Fue9t148uMm2KNVcn76?=
 =?iso-8859-1?Q?lWluzIykIS+T+ErwKa3IU0zyrqIDyEQOV6nbYufZX0rIqC2FmPl85VGP9Z?=
 =?iso-8859-1?Q?CaXDH/7ymACYSIPr3vZe6eGmmp31BhnXwq/+24hCg+220/LskYHMwdKzyh?=
 =?iso-8859-1?Q?W2QRY4RFg+a3VRW/QxMqHgADwMwm0RVKLqhZRVifUJuiU7g+infw4l4Xr+?=
 =?iso-8859-1?Q?3Yu2SfksndneLhLNl18FNQYqnDjQxjp0VrgtAmeaD7Bf3J/sGR4MZjnJUV?=
 =?iso-8859-1?Q?2wWTkCMqM6gHxIpPjLfC8dsNxO+txFxqweJ/hQYjV1Sg8IbABPfXzSN6/H?=
 =?iso-8859-1?Q?VnX5/gHxIn642X8kWJKs9wMFZ6k+3RaonzNY1sI9ETgqmwpCzfFb8i5BCF?=
 =?iso-8859-1?Q?xg7EHrfEjyBXrNJz5cI606XEotAi+zWLWIxFLpevEoylaFh4Wlu1FRHFHk?=
 =?iso-8859-1?Q?D2mEI311ob5nV/+mdby4nAcWp9njrJR/QdGD+RU6kYpy279iaa8lQ3BLoK?=
 =?iso-8859-1?Q?R6U5H4tDDLaGC6Xr5TzBPjnI1lIHjx3pfFPexQvSlsJsq0HNqnC1q5kX7W?=
 =?iso-8859-1?Q?3LysyJEHolRKod5jOuJzjmWOb/DfkviZLcsd5dmm4zxz0CiHkEreqkwONQ?=
 =?iso-8859-1?Q?YAqH6ALA1HJQSHnv4tfezUuitaoWsCesNswVcK4OoXcWu1MWymsOgcu1r8?=
 =?iso-8859-1?Q?N0Px+dInr+KWkEVgR0o/pQeVB8XsACcpgVXtlwOFB3JlutWhZpYI22VMy/?=
 =?iso-8859-1?Q?NYLsi7LbikJHYsMybJ6LwkIbLpJjmdKUJbpBvNUAE4BE87T6EGlFdfhdEv?=
 =?iso-8859-1?Q?OwmHQG+43ZHr0aD/zLb64XQE1ZwsV0JEttCtQ+GHpcuoAFnvHNznUwrx93?=
 =?iso-8859-1?Q?ldiMMcER+8lWlzphUaRhkRIX++B44dpPPSuu0IH5IyrtQTr0slzwfExHvj?=
 =?iso-8859-1?Q?80djjtntdQbwvkIbLAxY6/H5L5lhhPN5QLsmkDELCiGALWCuJY5mLOzXvu?=
 =?iso-8859-1?Q?guxFKFV023VAjJFiBPBQ1zNY9axKFqd5cdLJIe787nu9UtU4cyZB02VvFX?=
 =?iso-8859-1?Q?v55xuwt0PegBUy7cf/rElBHuXEDPWhM9kTRAnFbUXENt9ZSB48PgTgmgwa?=
 =?iso-8859-1?Q?dppoUcMlzhHW+HsjWZHh25qNmr7aizbQPL8UB+wXpXA8Q/HHnkSDlXRJaf?=
 =?iso-8859-1?Q?m1qwQnBR1gpZs=3D?=
Content-Type: text/plain; charset="iso-8859-1"
Content-Transfer-Encoding: quoted-printable
Precedence: bulk
X-Mailing-List: linux-kernel@vger.kernel.org
List-Id: <linux-kernel.vger.kernel.org>
List-Subscribe: <mailto:linux-kernel+subscribe@vger.kernel.org>
List-Unsubscribe: <mailto:linux-kernel+unsubscribe@vger.kernel.org>
MIME-Version: 1.0
X-OriginatorOrg: Nvidia.com
X-MS-Exchange-CrossTenant-AuthAs: Internal
X-MS-Exchange-CrossTenant-AuthSource: SA1PR12MB7199.namprd12.prod.outlook.com
X-MS-Exchange-CrossTenant-Network-Message-Id: fcb854af-e06d-4a06-0195-08dc289703f0
X-MS-Exchange-CrossTenant-originalarrivaltime: 08 Feb 2024 11:13:45.0875
 (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: ehHnZDppmdrBhHCxCBCa5AtwaJLkNh0YLm+d1oTkOq2JShaNDl0gF16F57FPe2yXXkiClTRC4VkXeEeOqvRJOw==
X-MS-Exchange-Transport-CrossTenantHeadersStamped: DM6PR12MB4943

>> >>=0A=
>> >> If mem_count =3D=3D 0, going through nvgrace_gpu_map_and_read() is no=
t=0A=
>> >> necessary.=0A=
>> >=0A=
>> > Harmless, other than the possibly unnecessary call through to=0A=
>> > nvgrace_gpu_map_device_mem().=A0 Maybe both=0A=
>> nvgrace_gpu_map_and_read()=0A=
>> > and nvgrace_gpu_map_and_write() could conditionally return 0 as their=
=0A=
>> > first operation when !mem_count.=A0 Thanks,=0A=
>> >=0A=
>> >Alex=0A=
>>=0A=
>> IMO, this seems like adding too much code to reduce the call length for =
a=0A=
>> very specific case. If there aren't any strong opinion on this, I'm plan=
ning to=0A=
>> leave this code as it is.=0A=
>=0A=
> a slight difference. if mem_count=3D=3D0 the result should always succeed=
=0A=
> no matter nvgrace_gpu_map_device_mem() succeeds or not. Of course=0A=
> if it fails it's already a big problem probably nobody cares about the su=
btle=0A=
> difference when reading non-exist range.=0A=
>=0A=
> but regarding to readability it's still clearer:=0A=
>=0A=
> if (mem_count)=0A=
>=A0=A0=A0=A0=A0=A0=A0 nvgrace_gpu_map_and_read();=0A=
=0A=
Makes sense. I'll change it.=