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FROMLIST: 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>
Bug: 140290589
Link: https://lore.kernel.org/lkml/20191121114918.2293-5-will@kernel.org/
Signed-off-by: Will Deacon <willdeacon@google.com>
Change-Id: I8f6a8aad8c41faa51df9c3a440c8b80c74e3ce8a
This commit is contained in:
Will Deacon 2019-11-08 12:56:09 +00:00 committed by Todd Kjos
parent 548ec40f5d
commit baf3e174b8
2 changed files with 19 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

19
drivers/iommu/iommu.c
View File

@ -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,

2
include/linux/iommu.h
View File

@ -245,6 +245,7 @@ struct iommu_iotlb_gather {
* @sva_get_pasid: Get PASID associated to a SVA handle
* @page_response: handle page request response
* @pgsize_bitmap: bitmap of all possible supported page sizes
* @owner: Driver module providing these ops
*/
struct iommu_ops {
bool (*capable)(enum iommu_cap);
@ -308,6 +309,7 @@ struct iommu_ops {
struct iommu_page_response *msg);
unsigned long pgsize_bitmap;
struct module *owner;
};
/**