[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-ID: <20220209133355.GY4160@nvidia.com>
Date: Wed, 9 Feb 2022 09:33:55 -0400
From: Jason Gunthorpe <jgg@...dia.com>
To: Lu Baolu <baolu.lu@...ux.intel.com>
Cc: Joerg Roedel <joro@...tes.org>,
Christoph Hellwig <hch@...radead.org>,
Ben Skeggs <bskeggs@...hat.com>,
Kevin Tian <kevin.tian@...el.com>,
Ashok Raj <ashok.raj@...el.com>, Will Deacon <will@...nel.org>,
Robin Murphy <robin.murphy@....com>,
Alex Williamson <alex.williamson@...hat.com>,
Eric Auger <eric.auger@...hat.com>,
Liu Yi L <yi.l.liu@...el.com>,
Jacob jun Pan <jacob.jun.pan@...el.com>,
David Airlie <airlied@...ux.ie>,
Daniel Vetter <daniel@...ll.ch>,
Thierry Reding <thierry.reding@...il.com>,
Jonathan Hunter <jonathanh@...dia.com>,
iommu@...ts.linux-foundation.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2 07/10] iommu: Use right way to retrieve iommu_ops
On Tue, Feb 08, 2022 at 09:25:56AM +0800, Lu Baolu wrote:
> The common iommu_ops is hooked to both device and domain. When a helper
> has both device and domain pointer, the way to get the iommu_ops looks
> messy in iommu core. This sorts out the way to get iommu_ops. The device
> related helpers go through device pointer, while the domain related ones
> go through domain pointer.
>
> Signed-off-by: Lu Baolu <baolu.lu@...ux.intel.com>
> ---
> include/linux/iommu.h | 14 ++++++++++++++
> drivers/iommu/iommu.c | 20 +++++++++++---------
> 2 files changed, 25 insertions(+), 9 deletions(-)
> diff --git a/include/linux/iommu.h b/include/linux/iommu.h
> index 9ffa2e88f3d0..eb2684f95018 100644
> --- a/include/linux/iommu.h
> +++ b/include/linux/iommu.h
> @@ -381,6 +381,20 @@ static inline void iommu_iotlb_gather_init(struct iommu_iotlb_gather *gather)
> };
> }
>
> +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);
IMHO this is overzealous. The kernel will reliably crash on null
dereference here, I'm not sure this adds much. But either way:
Reviewed-by: Jason Gunthorpe <jgg@...dia.com>
Jason
Powered by blists - more mailing lists