From: Lu Baolu <baolu.lu@linux.intel.com>
To: Joerg Roedel <joro@8bytes.org>
Cc: baolu.lu@linux.intel.com, Jason Gunthorpe <jgg@nvidia.com>,
Christoph Hellwig <hch@infradead.org>,
Ben Skeggs <bskeggs@redhat.com>,
Kevin Tian <kevin.tian@intel.com>,
Ashok Raj <ashok.raj@intel.com>, Will Deacon <will@kernel.org>,
Robin Murphy <robin.murphy@arm.com>,
Alex Williamson <alex.williamson@redhat.com>,
Eric Auger <eric.auger@redhat.com>, Liu Yi L <yi.l.liu@intel.com>,
Jacob jun Pan <jacob.jun.pan@intel.com>,
David Airlie <airlied@linux.ie>, Daniel Vetter <daniel@ffwll.ch>,
Thierry Reding <thierry.reding@gmail.com>,
Jonathan Hunter <jonathanh@nvidia.com>,
iommu@lists.linux-foundation.org, linux-kernel@vger.kernel.org,
Christoph Hellwig <hch@lst.de>
Subject: Re: [PATCH v3 07/10] iommu: Use right way to retrieve iommu_ops
Date: Tue, 15 Feb 2022 09:46:56 +0800 [thread overview]
Message-ID: <0dd0f4c9-37a6-0418-3f19-22c40ccc8265@linux.intel.com> (raw)
In-Reply-To: <YgpP7AhY5hd/DX/C@8bytes.org>
On 2/14/22 8:49 PM, Joerg Roedel wrote:
> On Mon, Feb 14, 2022 at 09:55:35AM +0800, Lu Baolu wrote:
>> +static inline const struct iommu_ops *dev_iommu_ops(struct device *dev)
>> +{
>> + /*
>> + * Assume that valid ops must be installed if iommu_probe_device()
>> + * has succeeded. The device ops are essentially for internal use
>> + * within the IOMMU subsystem itself, so we should be able to trust
>> + * ourselves not to misuse the helper.
>> + */
>> + WARN_ON(!dev || !dev->iommu || !dev->iommu->iommu_dev ||
>> + !dev->iommu->iommu_dev->ops);
>
> There is no need for this WARN_ON, the code will oops anyway when one of
> the pointers checked here is NULL.
>
We really don't need to WARN_ON intermediate null pointers. But I would
argue that we could add a WARN() on null dev->iommu->iommu_dev->ops, so
that callers have no need to check the returned ops.
Best regards,
baolu
next prev parent reply other threads:[~2022-02-15 1:48 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-02-14 1:55 [PATCH v3 00/10] iommu cleanup and refactoring Lu Baolu
2022-02-14 1:55 ` [PATCH v3 01/10] iommu/vt-d: Remove guest pasid related callbacks Lu Baolu
2022-02-14 1:55 ` [PATCH v3 02/10] iommu: Remove guest pasid related interfaces and definitions Lu Baolu
2022-02-14 1:55 ` [PATCH v3 03/10] iommu/vt-d: Remove aux-domain related callbacks Lu Baolu
2022-02-14 1:55 ` [PATCH v3 04/10] iommu: Remove aux-domain related interfaces and iommu_ops Lu Baolu
2022-02-14 1:55 ` [PATCH v3 05/10] iommu: Remove apply_resv_region Lu Baolu
2022-02-14 1:55 ` [PATCH v3 06/10] drm/nouveau/device: Get right pgsize_bitmap of iommu_domain Lu Baolu
2022-02-14 12:52 ` Joerg Roedel
2022-02-15 2:08 ` Lu Baolu
2022-02-14 1:55 ` [PATCH v3 07/10] iommu: Use right way to retrieve iommu_ops Lu Baolu
2022-02-14 12:49 ` Joerg Roedel
2022-02-15 1:46 ` Lu Baolu [this message]
2022-02-15 2:01 ` Lu Baolu
2022-02-14 1:55 ` [PATCH v3 08/10] iommu: Remove unused argument in is_attach_deferred Lu Baolu
2022-02-14 1:55 ` [PATCH v3 09/10] iommu: Use dev_iommu_ops() helper Lu Baolu
2022-02-14 13:26 ` Jason Gunthorpe
2022-02-15 1:39 ` Lu Baolu
2022-02-14 1:55 ` [PATCH v3 10/10] iommu: Split struct iommu_ops Lu Baolu
2022-02-14 14:14 ` [PATCH v3 00/10] iommu cleanup and refactoring Joerg Roedel
2022-02-15 2:05 ` Lu Baolu
2022-02-15 9:17 ` Joerg Roedel
2022-02-16 2:56 ` Lu Baolu
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