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Mon, 4 Aug 2025 10:44:30 -0700 Date: Mon, 4 Aug 2025 10:44:30 -0700 From: Nicolin Chen To: Richard Gemego , Pranjal Shrivastava CC: , , , , Quan Zhou Subject: Re: [PATCH] iommufd: fix returns ENOENT in iommufd_viommu_get_vdev_id() Message-ID: References: <20250804100859.3462571-1-richardgemego@gmail.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: X-NV-OnPremToCloud: AnonymousSubmission X-EOPAttributedMessage: 0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: CH3PEPF0000000D:EE_|SJ2PR12MB9240:EE_ X-MS-Office365-Filtering-Correlation-Id: 027ab62c-b9aa-41d3-d815-08ddd37ea1ff X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|1800799024|36860700013|376014|82310400026|7053199007; X-Microsoft-Antispam-Message-Info: =?us-ascii?Q?Mus1C9qM9gvCLsq0Z9gv3gPezXkI3+8fnuK+EgNlRzhtxMOddbgVAK197oPA?= =?us-ascii?Q?KqNI067/Ldz+rGrB4JILF7uPNVk6uqpxg9CdB/B7sBl7cCxD4wNk0eug/1H4?= =?us-ascii?Q?tv5b+9Jh0BuW+DyB9OsRw1swRBYZPVylMTswuwxa5+TQS6ZiEzbbO/0WXsNF?= =?us-ascii?Q?5DVMyOBKiMyGM8k8kcMv8K5s079ycYLs5cnrhCTMxNMoP92Z34oEtIKr2Nrh?= =?us-ascii?Q?X10vT39da4FbvBVXHdR+DSg4NGHyxGDGS0LzYzuYIARMikmJXYE9sdOVNByi?= =?us-ascii?Q?g4L+pMA/X/QLnqVBLiO1MQv4HyXUSOmqfgeftO8MtvWg2ZS302F6lCmnr78K?= =?us-ascii?Q?UK1gLEA98H7IVaDXEKGBI+O+cOKj6VMNVohYEzTR8gRu9OaE0koBCGpZGKA+?= =?us-ascii?Q?87VUzpb4ibm9ndWIKLhgMtMaIOtfh140XrsimZdcRbPX6DP62R27+r2vftWU?= =?us-ascii?Q?X/Oq98OxLK1Mywg9FU7JtMh0hxreqnnMbMqm7C3oFkb0TYuEfyOkA+4KemA9?= =?us-ascii?Q?sKOnxTeZBdNA2zHPyfK9HBXvHyJJHBpeeJh0c+PvE/9yRphBXcu3cx/k3iT2?= =?us-ascii?Q?o1p41V0d4UWepRnNCL3/OzLn/tB2vj28WS2+s99y+pNpZbggFraoZA2Tn8aQ?= =?us-ascii?Q?xn6z6m/7DGEYoRE8HTNpojqKsJi6Py1ZP7Gck47UXH5R9lH/KaBL8elR+tZm?= =?us-ascii?Q?PDufytUAw2MZE4821sJa5IKgrGj3Lp/DLWqnFDR9d+Io2wDb/mvsKxGXTgMy?= =?us-ascii?Q?DRoPeAijnjieiyAGDcPzxhkTg9O5+i7hKSHChwnrKfqT8jY1Kb/Awct09fbg?= =?us-ascii?Q?n7rlzSQCszlVZgBw4u08F9PfJioCTrQgVIEq3YFbPvV0msPU6Pc4nq7ujtxv?= =?us-ascii?Q?HaeFjoQmalWjw4NGMNsnhpY6bX5MM6tveGfGBZ4Sj/44MAm8SoSdLMnE4jvN?= =?us-ascii?Q?E0lMZautH2KAv4ojhdEMxMn7jWyH0N+FfdtmyPuVPyrUM6AV32ismr3MHjOJ?= =?us-ascii?Q?yyEfBrrQIST/M/gOY3wsDT/KJhEBukN/TxmCNNl21+lgUzYUzIGIqqwrxZmG?= =?us-ascii?Q?Zkw7LVl45PkOa1SUShuzo5rZXQJ3DF6QlVw38AwT2SMDV5GEYDxoYByVNS/j?= =?us-ascii?Q?XeamCXyhTNrUoJkko7HQrBy32EwF2OtSrDQgBqTY0OMgLnIt47PTXs+IOosA?= =?us-ascii?Q?/BreQRZ/UwWI2bryp75RCZaTmNwSNgmnsDqEDlEU2D5FOOu7XmVgdM2WzNo/?= =?us-ascii?Q?JZosW06pCL08GTSUtytv2/kyns6xhMnnOjXUbiY2UsOhnUMr0mcUGH1qXLln?= =?us-ascii?Q?EhrwMr2XCb5WqDRWkDmWvf8DdDBVL3oAkSgPDnvuKmCDPsh/l2iKH00v5a4Z?= =?us-ascii?Q?PQ41/Pvmg1ZckT7Mn/dHJ819zJuijyHWDkl2vt7ffqs0iVkiEyGqm+X412Zo?= =?us-ascii?Q?GjElwCgaWy+XY6YWmG/gv2QWU5dxyO9CQ+1eb01ux2ojHQquj78WIGtumvIK?= =?us-ascii?Q?rc4QDoYJDHywt0F/X+7WID8+o+cw7i/0vxxR?= X-Forefront-Antispam-Report: CIP:216.228.117.161;CTRY:US;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:mail.nvidia.com;PTR:dc6edge2.nvidia.com;CAT:NONE;SFS:(13230040)(1800799024)(36860700013)(376014)(82310400026)(7053199007);DIR:OUT;SFP:1101; X-OriginatorOrg: Nvidia.com X-MS-Exchange-CrossTenant-OriginalArrivalTime: 04 Aug 2025 17:44:59.1443 (UTC) X-MS-Exchange-CrossTenant-Network-Message-Id: 027ab62c-b9aa-41d3-d815-08ddd37ea1ff X-MS-Exchange-CrossTenant-Id: 43083d15-7273-40c1-b7db-39efd9ccc17a X-MS-Exchange-CrossTenant-OriginalAttributedTenantConnectingIp: TenantId=43083d15-7273-40c1-b7db-39efd9ccc17a;Ip=[216.228.117.161];Helo=[mail.nvidia.com] X-MS-Exchange-CrossTenant-AuthSource: CH3PEPF0000000D.namprd04.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Anonymous X-MS-Exchange-CrossTenant-FromEntityHeader: HybridOnPrem X-MS-Exchange-Transport-CrossTenantHeadersStamped: SJ2PR12MB9240 On Mon, Aug 04, 2025 at 11:25:42AM +0000, Pranjal Shrivastava wrote: > On Mon, Aug 04, 2025 at 06:08:59PM +0800, Richard Gemego wrote: > > In iommufd_viommu_get_vdev_id(), if viommu does not have any vdevs, fix > > this func to return 0 instead of ENOENT. I think this is missing some justification explaining why this is a fix. > > Fixes: ea94b211c548 ("iommufd/viommu: Add iommufd_viommu_get_vdev_id helper") > > Signed-off-by: Richard Gemego > > Signed-off-by: Quan Zhou > > --- > > drivers/iommu/iommufd/driver.c | 1 + > > 1 file changed, 1 insertion(+) > > > > diff --git a/drivers/iommu/iommufd/driver.c b/drivers/iommu/iommufd/driver.c > > index 922cd1fe7ec2..ad635af8555b 100644 > > --- a/drivers/iommu/iommufd/driver.c > > +++ b/drivers/iommu/iommufd/driver.c > > @@ -68,6 +68,7 @@ int iommufd_viommu_get_vdev_id(struct iommufd_viommu *viommu, > > break; > > } > > } > > + if (!index) > > + rc = 0; > > xa_unlock(&viommu->vdevs); > > return rc; > > } > > I'm afraid, I don't understand the motivation behind this? IIUC, if a > dev is not associated to the vIOMMU -ENOENT is returned. This patch > seems to be returning 0 when the xarray is empty. The issue is that > returning 0, would indicate the caller that `*vdev_id` holds a valid > value which doesn't seem to be the case here? The function is designed to return -ENOENT for an empty xarray: /* Return -ENOENT if device is not associated to the vIOMMU */ And 0 would be a valid vdev ID in the xarray. Nicolin