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authorWill Deacon <will@kernel.org>2019-12-19 12:03:41 +0000
committerJoerg Roedel <jroedel@suse.de>2019-12-23 14:06:05 +0100
commit25f003de987aed630db265ceae9cd978537a3f80 (patch)
tree6a53d13ae038b397f968766a1a5c7fa9b1b5fc71 /drivers/iommu/iommu.c
parent1a373a78b8e2fae1d61dd9c5ed22472045d83d24 (diff)
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drivers/iommu: Take a ref to the IOMMU driver prior to ->add_device()
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>
Diffstat (limited to 'drivers/iommu/iommu.c')
-rw-r--r--drivers/iommu/iommu.c19
1 files changed, 17 insertions, 2 deletions
diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
index 3abe19ecbcd1..32ceda1d5031 100644
--- a/drivers/iommu/iommu.c
+++ b/drivers/iommu/iommu.c
@@ -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,