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xen/grant-dma-iommu: Implement a dummy probe_device() callback

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Update stub IOMMU driver (which main purpose is to reuse generic
IOMMU device-tree bindings by Xen grant DMA-mapping layer on Arm)
according to the recent changes done in the following
commit 57365a04c9 ("iommu: Move bus setup to IOMMU device registration").

With probe_device() callback being called during IOMMU device registration,
the uninitialized callback just leads to the "kernel NULL pointer
dereference" issue during boot. Fix that by adding a dummy callback.

Looks like the release_device() callback is not mandatory to be
implemented as IOMMU framework makes sure that callback is initialized
before dereferencing.

Reported-by: Viresh Kumar <viresh.kumar@linaro.org>
Fixes: 57365a04c9 ("iommu: Move bus setup to IOMMU device registration")
Signed-off-by: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>
Tested-by: Viresh Kumar <viresh.kumar@linaro.org>
Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>
Link: https://lore.kernel.org/r/20230208153649.3604857-1-olekstysh@gmail.com
Signed-off-by: Juergen Gross <jgross@suse.com>
This commit is contained in:
Oleksandr Tyshchenko 2023-02-08 17:36:49 +02:00 committed by Juergen Gross
parent c70b7741dd
commit 2062f9fb64
1 changed files with 9 additions and 2 deletions
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11
drivers/xen/grant-dma-iommu.c
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@ -16,8 +16,15 @@ struct grant_dma_iommu_device {
struct iommu_device iommu;
};
/* Nothing is really needed here */
static const struct iommu_ops grant_dma_iommu_ops;
static struct iommu_device *grant_dma_iommu_probe_device(struct device *dev)
{
return ERR_PTR(-ENODEV);
}
/* Nothing is really needed here except a dummy probe_device callback */
static const struct iommu_ops grant_dma_iommu_ops = {
.probe_device = grant_dma_iommu_probe_device,
};
static const struct of_device_id grant_dma_iommu_of_match[] = {
{ .compatible = "xen,grant-dma" },