iommu/of: Take a ref to the IOMMU driver during ->of_xlate()

Ensure that we hold a reference to the IOMMU driver module while calling
the '->of_xlate()' callback during early device probing.

Signed-off-by: Will Deacon <will@kernel.org>
Tested-by: John Garry <john.garry@huawei.com> # smmu v3
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Joerg Roedel <jroedel@suse.de>
This commit is contained in:
Will Deacon 2019-12-19 12:03:42 +00:00 committed by Joerg Roedel
parent 25f003de98
commit 386dce2788

View File

@ -8,11 +8,12 @@
#include <linux/export.h>
#include <linux/iommu.h>
#include <linux/limits.h>
#include <linux/pci.h>
#include <linux/module.h>
#include <linux/msi.h>
#include <linux/of.h>
#include <linux/of_iommu.h>
#include <linux/of_pci.h>
#include <linux/pci.h>
#include <linux/slab.h>
#include <linux/fsl/mc.h>
@ -91,16 +92,16 @@ static int of_iommu_xlate(struct device *dev,
{
const struct iommu_ops *ops;
struct fwnode_handle *fwnode = &iommu_spec->np->fwnode;
int err;
int ret;
ops = iommu_ops_from_fwnode(fwnode);
if ((ops && !ops->of_xlate) ||
!of_device_is_available(iommu_spec->np))
return NO_IOMMU;
err = iommu_fwspec_init(dev, &iommu_spec->np->fwnode, ops);
if (err)
return err;
ret = iommu_fwspec_init(dev, &iommu_spec->np->fwnode, ops);
if (ret)
return ret;
/*
* The otherwise-empty fwspec handily serves to indicate the specific
* IOMMU device we're waiting for, which will be useful if we ever get
@ -109,7 +110,12 @@ static int of_iommu_xlate(struct device *dev,
if (!ops)
return driver_deferred_probe_check_state(dev);
return ops->of_xlate(dev, iommu_spec);
if (!try_module_get(ops->owner))
return -ENODEV;
ret = ops->of_xlate(dev, iommu_spec);
module_put(ops->owner);
return ret;
}
struct of_pci_iommu_alias_info {