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drivers/iommu: Take a ref to the IOMMU driver prior to ->add_device()

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To avoid accidental removal of an active IOMMU driver module, take a
reference to the driver module in 'iommu_probe_device()' immediately
prior to invoking the '->add_device()' callback and hold it until the
after the device has been removed by '->remove_device()'.

Suggested-by: Joerg Roedel <joro@8bytes.org>
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 12:03:41 +00:00
committed by Joerg Roedel
parent 1a373a78b8
commit 25f003de98
2 changed files with 20 additions and 3 deletions
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19
drivers/iommu/iommu.c
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@@ -22,6 +22,7 @@
#include <linux/bitops.h>
#include <linux/property.h>
#include <linux/fsl/mc.h>
#include <linux/module.h>
#include <trace/events/iommu.h>
static struct kset *iommu_group_kset;
@@ -185,10 +186,21 @@ int iommu_probe_device(struct device *dev)
if (!iommu_get_dev_param(dev))
return -ENOMEM;
if (!try_module_get(ops->owner)) {
ret = -EINVAL;
goto err_free_dev_param;
}
ret = ops->add_device(dev);
if (ret)
iommu_free_dev_param(dev);
goto err_module_put;
return 0;
err_module_put:
module_put(ops->owner);
err_free_dev_param:
iommu_free_dev_param(dev);
return ret;
}
@@ -199,7 +211,10 @@ void iommu_release_device(struct device *dev)
if (dev->iommu_group)
ops->remove_device(dev);
iommu_free_dev_param(dev);
if (dev->iommu_param) {
module_put(ops->owner);
iommu_free_dev_param(dev);
}
}
static struct iommu_domain *__iommu_domain_alloc(struct bus_type *bus,