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iommu: Keep dev->iommu state consistent

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[ Upstream commit 3832862eb9c4dfa0e80b2522bfaedbc8a43de97d ]

At the moment, if of_iommu_configure() allocates dev->iommu itself via
iommu_fwspec_init(), then suffers a DT parsing failure, it cleans up the
fwspec but leaves the empty dev_iommu hanging around. So far this is
benign (if a tiny bit wasteful), but we'd like to be able to reason
about dev->iommu having a consistent and unambiguous lifecycle. Thus
make sure that the of_iommu cleanup undoes precisely whatever it did.

Signed-off-by: Robin Murphy <robin.murphy@arm.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Link: https://lore.kernel.org/r/d219663a3f23001f23d520a883ac622d70b4e642.1740753261.git.robin.murphy@arm.com
Signed-off-by: Joerg Roedel <jroedel@suse.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Robin Murphy
2025-02-28 15:46:32 +00:00
committed by Greg Kroah-Hartman
parent a21f1607d0
commit 063ad8885c
3 changed files with 8 additions and 2 deletions
Download Patch File Download Diff File Expand all files Collapse all files

2
drivers/iommu/iommu-priv.h
View File

@@ -17,6 +17,8 @@ static inline const struct iommu_ops *dev_iommu_ops(struct device *dev)
return dev->iommu->iommu_dev->ops;
}
void dev_iommu_free(struct device *dev);
const struct iommu_ops *iommu_ops_from_fwnode(const struct fwnode_handle *fwnode);
static inline const struct iommu_ops *iommu_fwspec_ops(struct iommu_fwspec *fwspec)

2
drivers/iommu/iommu.c
View File

@@ -347,7 +347,7 @@ static struct dev_iommu *dev_iommu_get(struct device *dev)
return param;
}
static void dev_iommu_free(struct device *dev)
void dev_iommu_free(struct device *dev)
{
struct dev_iommu *param = dev->iommu;

6
drivers/iommu/of_iommu.c
View File

@@ -118,6 +118,7 @@ static void of_pci_check_device_ats(struct device *dev, struct device_node *np)
int of_iommu_configure(struct device *dev, struct device_node *master_np,
const u32 *id)
{
bool dev_iommu_present;
int err;
if (!master_np)
@@ -129,6 +130,7 @@ int of_iommu_configure(struct device *dev, struct device_node *master_np,
mutex_unlock(&iommu_probe_device_lock);
return 0;
}
dev_iommu_present = dev->iommu;
/*
* We don't currently walk up the tree looking for a parent IOMMU.
@@ -149,8 +151,10 @@ int of_iommu_configure(struct device *dev, struct device_node *master_np,
err = of_iommu_configure_device(master_np, dev, id);
}
if (err)
if (err && dev_iommu_present)
iommu_fwspec_free(dev);
else if (err && dev->iommu)
dev_iommu_free(dev);
mutex_unlock(&iommu_probe_device_lock);
if (!err && dev->bus)