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Wed, 19 Feb 2025 08:48:47 -0800 Date: Wed, 19 Feb 2025 08:48:46 -0800 From: Nicolin Chen To: Yi Liu CC: , , , , , , Subject: Re: [PATCH 1/5] iommu: Make @handle mandatory in iommu_{attach|replace}_group_handle() Message-ID: References: <20250212060540.261436-1-yi.l.liu@intel.com> <20250212060540.261436-2-yi.l.liu@intel.com> Precedence: bulk X-Mailing-List: iommu@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Disposition: inline In-Reply-To: <20250212060540.261436-2-yi.l.liu@intel.com> X-NV-OnPremToCloud: AnonymousSubmission X-EOPAttributedMessage: 0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: CY4PEPF0000E9D5:EE_|CY8PR12MB7196:EE_ X-MS-Office365-Filtering-Correlation-Id: 5582bcd7-25fb-4679-d9b1-08dd51054ee2 X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|376014|82310400026|1800799024|36860700013|7053199007; X-Microsoft-Antispam-Message-Info: =?us-ascii?Q?jgKrRnt+g8zXdW0+MoWJJHqqXN5n1h6Sh+VmxAv4EeU0j3vfzmU3Ggt6EI2I?= =?us-ascii?Q?x++Fowdy4i2kIX6NJBegHMbrmSo0xXctGxmnIc2sGcyWwPz3lcQ7oJ1ntxLy?= =?us-ascii?Q?UjC6hBoFHEibOeR4mTpMM4PV2yqvq2otw+ST6Jsk+kn0l98vgnFUOOJhkt3I?= =?us-ascii?Q?VkQF4xH8QBsOm6VKY9Wy5FYc4TKzZWklBq/Z9mejfyzVF1+eu/sm3sSHQIFU?= =?us-ascii?Q?VkaCMffDc+E7hfWU+7dDFO/uDH0ltcrUBogUYmEaIHZ3TmFPm775ISS/25yL?= =?us-ascii?Q?M2USbK20Bryg7b9exfPPNd09mMxH/XHkfgmIOOVVs/x64wMiX0io29kuLbHU?= =?us-ascii?Q?LmH1drrmoVt4MJKkTjfFrRDu1r/VXzp5uHiDx0PB3a9L/Itri4i6uY6xUXmu?= =?us-ascii?Q?BmSjtdxcE+TROTDsDq1GeEtueDaSPj11+vYM27DMJelt0qmCOywAXQ3fqiQ4?= =?us-ascii?Q?zVoexcT/jVocJ8o+mYL1Sekbz/OpwngHUXn5eafrhXuKxy6ws0q5/pPkl8qp?= =?us-ascii?Q?htmxXgR64sRqa6vyPNVFREioo78p6cqYmjB6r7DKgcX7SqX/iBUPP01vf4Or?= =?us-ascii?Q?PX4dfIqlUWuGdixR8oy19sR93YI2WwtJYS2ep6Ztgo5KdvSeANRp416uYpY3?= =?us-ascii?Q?3YRroZxsUz63po5hJLuUAug6OiZXww7Re6xZcKimNcgwO+xtAG3Ep4Xfs1B0?= =?us-ascii?Q?1L/pp2p3svDyIYtGT8BQvl93y9BbnZECDS9i0uZVMii1JTIJLtHzdG1WzWpt?= =?us-ascii?Q?qv84j8h7txNpGgmWCfUM0wZdo+LloOk7koKD+dFwP/IUG71NWikUvToPoSsl?= =?us-ascii?Q?fVyEjGzzSuqT1wL8Y2B4fTEDSSOura/PqLnXdShzOL+dohxvZcp5PA8E0UPG?= =?us-ascii?Q?bTN90gKMavalehV3H6X4gEG2vh/kP/3eK8K4AFVXl9Hf6w5NPOQNulIydzto?= =?us-ascii?Q?ayxxIhUYoogi3BbjEuS17SXKji6UYGPL/EWLXEjUsr+0l2EKJypQLh+R8/Ak?= =?us-ascii?Q?0K1vbofami0TMmBoMPw552GusPl+OQsi0F4rozcAbe5FGFjXowTCe9gCVVET?= =?us-ascii?Q?7kyQgLnoGShBpA0v9LKoPvEk1KHdNqjfuwnI10LNHGpUgbsT3djgNR6XOHOM?= =?us-ascii?Q?Y5/OG+6nbqp/xVbXzcpUurWoKG4/eyDQ/5TM3ZcgfL7VrhMAjSam77GIOweT?= =?us-ascii?Q?QtUwJ/lAruVTjxpHb9F40N/YjGcFNh0agHwqYMHfZsa48HJmisfkQGuXjHbm?= =?us-ascii?Q?NclAVGJHv2IE0wRKQwJ5NiReqfkGSHPN7GBrUT84Ce9rUEijzU78xfnzxCqh?= =?us-ascii?Q?RIj1jv8BcRLCfSRYb897KVIbxbRJSK/m+9ERN2z7RC5N/nf5cYioS+sAyvLF?= =?us-ascii?Q?4YwiCxncFYQN29Hndan/HisSqUmAlJ/BELlnjtfxQ0LSQz7d03SNst2xu7gH?= =?us-ascii?Q?BFOw3tMBeDEYodKV1f0/KUgZf5CayuxJKriSowK7IaEqT6aIW3GCghRxIGTy?= =?us-ascii?Q?T07kHShFZQVHh2U=3D?= X-Forefront-Antispam-Report: CIP:216.228.118.232;CTRY:US;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:mail.nvidia.com;PTR:dc7edge1.nvidia.com;CAT:NONE;SFS:(13230040)(376014)(82310400026)(1800799024)(36860700013)(7053199007);DIR:OUT;SFP:1101; X-OriginatorOrg: Nvidia.com X-MS-Exchange-CrossTenant-OriginalArrivalTime: 19 Feb 2025 16:48:59.5717 (UTC) X-MS-Exchange-CrossTenant-Network-Message-Id: 5582bcd7-25fb-4679-d9b1-08dd51054ee2 X-MS-Exchange-CrossTenant-Id: 43083d15-7273-40c1-b7db-39efd9ccc17a X-MS-Exchange-CrossTenant-OriginalAttributedTenantConnectingIp: TenantId=43083d15-7273-40c1-b7db-39efd9ccc17a;Ip=[216.228.118.232];Helo=[mail.nvidia.com] X-MS-Exchange-CrossTenant-AuthSource: CY4PEPF0000E9D5.namprd05.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Anonymous X-MS-Exchange-CrossTenant-FromEntityHeader: HybridOnPrem X-MS-Exchange-Transport-CrossTenantHeadersStamped: CY8PR12MB7196 On Tue, Feb 11, 2025 at 10:05:36PM -0800, Yi Liu wrote: > Caller of the two APIs always provide a valid handle, make @handle as > mandatory parameter. > > Signed-off-by: Yi Liu Reviewed-by: Nicolin Chen A side note here: > @@ -3511,8 +3511,10 @@ int iommu_attach_group_handle(struct iommu_domain *domain, > { > int ret; > > - if (handle) > - handle->domain = domain; > + if (!handle) > + return -EINVAL; > + > + handle->domain = domain; > > mutex_lock(&group->mutex); > ret = xa_insert(&group->pasid_array, IOMMU_NO_PASID, handle, GFP_KERNEL); > @@ -3568,16 +3570,15 @@ int iommu_replace_group_handle(struct iommu_group *group, > void *curr; > int ret; > > - if (!new_domain) > + if (!new_domain || !handle) > return -EINVAL; > > + handle->domain = new_domain; > + > mutex_lock(&group->mutex); So, we don't have the mutex fencing the handle->domain, since an attach handle is always a newly allocated one in the caller, and there won't be any potential race occurring to it. Yet, this feels like an implication, which we should have stated explicitly in the kdocs of these two functions? Thanks Nicolin