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b=P8Br78do7QwtwBSiNjMpmS9XJ4cA454VSDYhTLWrgUyE/BgU9vjuNo51wNodooIFwfc1QrI5V9KmR+GiZ2PriWloL9Jzy4LoR2XRyKQPh68wsOvehQ9Ewautad41d6y2KpFsmgWCOCxXdmb5BqPqKfxGnh/q5qjc4veSJj0Mgok= Authentication-Results: dkim=none (message not signed) header.d=none;dmarc=none action=none header.from=amd.com; Received: from BL4PR12MB9505.namprd12.prod.outlook.com (2603:10b6:208:591::16) by DS0PR12MB8367.namprd12.prod.outlook.com (2603:10b6:8:fd::17) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.21.339.11; Sat, 22 Aug 2026 13:55:36 +0000 Received: from BL4PR12MB9505.namprd12.prod.outlook.com ([fe80::73aa:eb8c:a86b:5a83]) by BL4PR12MB9505.namprd12.prod.outlook.com ([fe80::73aa:eb8c:a86b:5a83%5]) with mapi id 15.21.0339.010; Sat, 22 Aug 2026 13:55:36 +0000 Message-ID: <5f90bdcf-0ca5-42b4-98d1-807fe19990f2@amd.com> Date: Sat, 22 Aug 2026 19:25:29 +0530 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2 5/5] PCI/ATS: Mandate checking pci_ats_supported() before pci_prepare_ats() To: Pranjal Shrivastava , iommu@lists.linux.dev, linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org Cc: Joerg Roedel , Suravee Suthikulpanit , Ankit Soni , Jason Gunthorpe , Bjorn Helgaas , Samiullah Khawaja , Baolu Lu , Nicolin Chen References: <20260814015647.3370124-1-praan@google.com> <20260814015647.3370124-6-praan@google.com> Content-Language: en-US From: Vasant Hegde In-Reply-To: <20260814015647.3370124-6-praan@google.com> Content-Type: text/plain; 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While this provides > a silent safety check, it conflates support detection with configuration. > > Update pci_prepare_ats() to wrap the internal pci_ats_supported check in > a WARN_ON(). This mandates all callers to call pci_prepare_ats() only if > the function supports ATS. > > Update the function documentation to mention that callers must verify > ATS support (via pci_ats_supported()) before calling pci_prepare_ats(). > > Suggested-by: Baolu Lu > Reviewed-by: Nicolin Chen > Signed-off-by: Pranjal Shrivastava Reviewed-by: Vasant Hegde -Vasant