From: Nicolin Chen <nicolinc@nvidia.com>
To: Pranjal Shrivastava <praan@google.com>
Cc: <iommu@lists.linux.dev>, <linux-pci@vger.kernel.org>,
<linux-arm-kernel@lists.infradead.org>,
<linux-kernel@vger.kernel.org>, "Joerg Roedel" <joro@8bytes.org>,
Will Deacon <will@kernel.org>,
Bjorn Helgaas <bhelgaas@google.com>,
David Woodhouse <dwmw2@infradead.org>,
Lu Baolu <baolu.lu@linux.intel.com>,
Robin Murphy <robin.murphy@arm.com>,
"Suravee Suthikulpanit" <suravee.suthikulpanit@amd.com>,
Jason Gunthorpe <jgg@ziepe.ca>,
David Matlack <dmatlack@google.com>,
Samiullah Khawaja <skhawaja@google.com>,
Daniel Mentz <danielmentz@google.com>,
Pasha Tatashin <pasha.tatashin@soleen.com>,
Mostafa Saleh <smostafa@google.com>
Subject: Re: [PATCH v6 3/6] PCI/ATS: Mandate checking pci_ats_supported() before pci_prepare_ats()
Date: Fri, 29 May 2026 14:56:01 -0700 [thread overview]
Message-ID: <ahoLccjQvmoE90sx@Asurada-Nvidia> (raw)
In-Reply-To: <20260529111208.387412-4-praan@google.com>
On Fri, May 29, 2026 at 11:12:05AM +0000, Pranjal Shrivastava wrote:
> Currently, pci_prepare_ats() internally calls pci_ats_supported() and
> returns -EINVAL if the device does not support ATS. 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 <baolu.lu@linux.intel.com>
> Signed-off-by: Pranjal Shrivastava <praan@google.com>
Sashiko pointed out a bisect issue. So, you might want to reorder
a bit. The patch itself looks good to me.
Reviewed-by: Nicolin Chen <nicolinc@nvidia.com>
next prev parent reply other threads:[~2026-05-29 21:56 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-05-29 11:12 [PATCH v6 0/6] iommu: Standardize ATS robustness and state tracking Pranjal Shrivastava
2026-05-29 11:12 ` [PATCH v6 1/6] PCI/ATS: Ensure pci_ats_supported() is PF-aware for VFs Pranjal Shrivastava
2026-05-29 11:12 ` [PATCH v6 2/6] PCI/ATS: Validate STU for VFs in pci_prepare_ats() Pranjal Shrivastava
2026-05-29 11:12 ` [PATCH v6 3/6] PCI/ATS: Mandate checking pci_ats_supported() before pci_prepare_ats() Pranjal Shrivastava
2026-05-29 21:56 ` Nicolin Chen [this message]
2026-05-31 17:06 ` Pranjal Shrivastava
2026-05-29 11:12 ` [PATCH v6 4/6] iommu/arm-smmu-v3: Standardize ATS enablement failure reporting Pranjal Shrivastava
2026-05-29 21:51 ` Nicolin Chen
2026-05-31 17:13 ` Pranjal Shrivastava
2026-05-29 11:12 ` [PATCH v6 5/6] iommu/vt-d: Fail probe on ATS configuration failure Pranjal Shrivastava
2026-05-29 11:12 ` [PATCH v6 6/6] iommu/amd: " Pranjal Shrivastava
2026-06-01 6:00 ` Ankit Soni
2026-06-01 6:20 ` Pranjal Shrivastava
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