Commit 2062f9fb authored by Oleksandr Tyshchenko's avatar Oleksandr Tyshchenko Committed by Juergen Gross
Browse files

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



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 57365a04 ("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: default avatarViresh Kumar <viresh.kumar@linaro.org>
Fixes: 57365a04 ("iommu: Move bus setup to IOMMU device registration")
Signed-off-by: default avatarOleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>
Tested-by: default avatarViresh Kumar <viresh.kumar@linaro.org>
Reviewed-by: default avatarStefano Stabellini <sstabellini@kernel.org>
Link: https://lore.kernel.org/r/20230208153649.3604857-1-olekstysh@gmail.com


Signed-off-by: default avatarJuergen Gross <jgross@suse.com>
parent c70b7741

drivers/xen/grant-dma-iommu.c

+9 −2
Original line number Diff line number Diff line
@@ -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" },