Hi Robin/Joerg,
> -----Original Message-----
> From: Shameer Kolothum [mailto:shameerali.kolothum.th...@huawei.com]
> Sent: 01 February 2021 12:41
> To: linux-kernel@vger.kernel.org; io...@lists.linux-foundation.org
> Cc: j...@8bytes.org; robin.mur...@arm.com; jean-phili...@linaro.org;
> w...@kernel.org; Zengtao (B) <prime.z...@hisilicon.com>;
> linux...@openeuler.org
> Subject: [Linuxarm] [PATCH v2] iommu: Check dev->iommu in iommu_dev_xxx
> functions
>
> The device iommu probe/attach might have failed leaving dev->iommu
> to NULL and device drivers may still invoke these functions resulting
> in a crash in iommu vendor driver code. Hence make sure we check that.
>
> Also added iommu_ops to the "struct dev_iommu" and set it if the dev
> is successfully associated with an iommu.
>
> Fixes: a3a195929d40 ("iommu: Add APIs for multiple domains per device")
> Signed-off-by: Shameer Kolothum <shameerali.kolothum.th...@huawei.com>
> ---
> v1 --> v2:
> -Added iommu_ops to struct dev_iommu based on the discussion with Robin.
> -Rebased against iommu-tree core branch.
A gentle ping on this...
Thanks,
Shameer
> ---
> drivers/iommu/iommu.c | 19 +++++++------------
> include/linux/iommu.h | 2 ++
> 2 files changed, 9 insertions(+), 12 deletions(-)
>
> diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
> index fd76e2f579fe..6023d0b7c542 100644
> --- a/drivers/iommu/iommu.c
> +++ b/drivers/iommu/iommu.c
> @@ -217,6 +217,7 @@ static int __iommu_probe_device(struct device *dev,
> struct list_head *group_list
> }
>
> dev->iommu->iommu_dev = iommu_dev;
> + dev->iommu->ops = iommu_dev->ops;
>
> group = iommu_group_get_for_dev(dev);
> if (IS_ERR(group)) {
> @@ -2865,10 +2866,8 @@ EXPORT_SYMBOL_GPL(iommu_fwspec_add_ids);
> */
> int iommu_dev_enable_feature(struct device *dev, enum
> iommu_dev_features feat)
> {
> - const struct iommu_ops *ops = dev->bus->iommu_ops;
> -
> - if (ops && ops->dev_enable_feat)
> - return ops->dev_enable_feat(dev, feat);
> + if (dev->iommu && dev->iommu->ops->dev_enable_feat)
> + return dev->iommu->ops->dev_enable_feat(dev, feat);
>
> return -ENODEV;
> }
> @@ -2881,10 +2880,8 @@
> EXPORT_SYMBOL_GPL(iommu_dev_enable_feature);
> */
> int iommu_dev_disable_feature(struct device *dev, enum
> iommu_dev_features feat)
> {
> - const struct iommu_ops *ops = dev->bus->iommu_ops;
> -
> - if (ops && ops->dev_disable_feat)
> - return ops->dev_disable_feat(dev, feat);
> + if (dev->iommu && dev->iommu->ops->dev_disable_feat)
> + return dev->iommu->ops->dev_disable_feat(dev, feat);
>
> return -EBUSY;
> }
> @@ -2892,10 +2889,8 @@
> EXPORT_SYMBOL_GPL(iommu_dev_disable_feature);
>
> bool iommu_dev_feature_enabled(struct device *dev, enum
> iommu_dev_features feat)
> {
> - const struct iommu_ops *ops = dev->bus->iommu_ops;
> -
> - if (ops && ops->dev_feat_enabled)
> - return ops->dev_feat_enabled(dev, feat);
> + if (dev->iommu && dev->iommu->ops->dev_feat_enabled)
> + return dev->iommu->ops->dev_feat_enabled(dev, feat);
>
> return false;
> }
> diff --git a/include/linux/iommu.h b/include/linux/iommu.h
> index 524ffc2ff64f..ff0c76bdfb67 100644
> --- a/include/linux/iommu.h
> +++ b/include/linux/iommu.h
> @@ -354,6 +354,7 @@ struct iommu_fault_param {
> * @fault_param: IOMMU detected device fault reporting data
> * @fwspec: IOMMU fwspec data
> * @iommu_dev: IOMMU device this device is linked to
> + * @ops: iommu-ops for talking to the iommu_dev
> * @priv: IOMMU Driver private data
> *
> * TODO: migrate other per device data pointers under iommu_dev_data,
> e.g.
> @@ -364,6 +365,7 @@ struct dev_iommu {
> struct iommu_fault_param *fault_param;
> struct iommu_fwspec *fwspec;
> struct iommu_device *iommu_dev;
> + const struct iommu_ops *ops;
> void *priv;
> };
>
> --
> 2.17.1
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