From: Will Deacon <will@kernel.org>
Date: Thu, 19 Dec 2019 12:03:42 +0000
Subject: iommu/of: Take a ref to the IOMMU driver during ->of_xlate()
Git-commit: 386dce2788eef626aaaa6a3ca32809ea7904581b
Patch-mainline: v5.6-rc1
References: bsc#1175713
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>
---
drivers/iommu/of_iommu.c | 18 ++++++++++++------
1 file changed, 12 insertions(+), 6 deletions(-)
--- a/drivers/iommu/of_iommu.c
+++ b/drivers/iommu/of_iommu.c
@@ -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
{
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
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 {