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Date: Wed, 11 Oct 2023 19:14:48 +0100
From: Robin Murphy <robin.murphy@....com>
To: joro@...tes.org, will@...nel.org
Cc: iommu@...ts.linux.dev, jgg@...dia.com, baolu.lu@...ux.intel.com,
linux-kernel@...r.kernel.org
Subject: [PATCH v5 1/7] iommu: Factor out some helpers
The pattern for picking the first device out of the group list is
repeated a few times now, so it's clearly worth factoring out, which
also helps hide the iommu_group_dev detail from places that don't need
to know. Similarly, the safety check for dev_iommu_ops() at certain
public interfaces starts looking a bit repetitive, and might not be
completely obvious at first glance, so let's factor that out for clarity
as well, in preparation for more uses of both.
Reviewed-by: Lu Baolu <baolu.lu@...ux.intel.com>
Signed-off-by: Robin Murphy <robin.murphy@....com>
---
v3: Rename dev_iommu_ops_valid() to reflect what it's actually checking,
rather than an implied consequence.
v4: Rebase, also catch the sneaky one in iommu_get_group_resv_regions()
which wasn't the full pattern (but really should be since it guards
the dev_iommu_ops() invocation in iommu_get_resv_regions()).
---
drivers/iommu/iommu.c | 56 ++++++++++++++++++++-----------------------
1 file changed, 26 insertions(+), 30 deletions(-)
diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
index f9f315d58a3a..5a3ce293a5de 100644
--- a/drivers/iommu/iommu.c
+++ b/drivers/iommu/iommu.c
@@ -368,6 +368,15 @@ static void dev_iommu_free(struct device *dev)
kfree(param);
}
+/*
+ * Internal equivalent of device_iommu_mapped() for when we care that a device
+ * actually has API ops, and don't want false positives from VFIO-only groups.
+ */
+static bool dev_has_iommu(struct device *dev)
+{
+ return dev->iommu && dev->iommu->iommu_dev;
+}
+
static u32 dev_iommu_get_max_pasids(struct device *dev)
{
u32 max_pasids = 0, bits = 0;
@@ -620,7 +629,7 @@ static void __iommu_group_remove_device(struct device *dev)
list_del(&device->list);
__iommu_group_free_device(group, device);
- if (dev->iommu && dev->iommu->iommu_dev)
+ if (dev_has_iommu(dev))
iommu_deinit_device(dev);
else
dev->iommu_group = NULL;
@@ -819,7 +828,7 @@ int iommu_get_group_resv_regions(struct iommu_group *group,
* Non-API groups still expose reserved_regions in sysfs,
* so filter out calls that get here that way.
*/
- if (!device->dev->iommu)
+ if (!dev_has_iommu(device->dev))
break;
INIT_LIST_HEAD(&dev_resv_regions);
@@ -1224,6 +1233,12 @@ void iommu_group_remove_device(struct device *dev)
}
EXPORT_SYMBOL_GPL(iommu_group_remove_device);
+static struct device *iommu_group_first_dev(struct iommu_group *group)
+{
+ lockdep_assert_held(&group->mutex);
+ return list_first_entry(&group->devices, struct group_device, list)->dev;
+}
+
/**
* iommu_group_for_each_dev - iterate over each device in the group
* @group: the group
@@ -1751,23 +1766,6 @@ __iommu_group_alloc_default_domain(struct iommu_group *group, int req_type)
return __iommu_group_domain_alloc(group, req_type);
}
-/*
- * Returns the iommu_ops for the devices in an iommu group.
- *
- * It is assumed that all devices in an iommu group are managed by a single
- * IOMMU unit. Therefore, this returns the dev_iommu_ops of the first device
- * in the group.
- */
-static const struct iommu_ops *group_iommu_ops(struct iommu_group *group)
-{
- struct group_device *device =
- list_first_entry(&group->devices, struct group_device, list);
-
- lockdep_assert_held(&group->mutex);
-
- return dev_iommu_ops(device->dev);
-}
-
/*
* req_type of 0 means "auto" which means to select a domain based on
* iommu_def_domain_type or what the driver actually supports.
@@ -1775,7 +1773,7 @@ static const struct iommu_ops *group_iommu_ops(struct iommu_group *group)
static struct iommu_domain *
iommu_group_alloc_default_domain(struct iommu_group *group, int req_type)
{
- const struct iommu_ops *ops = group_iommu_ops(group);
+ const struct iommu_ops *ops = dev_iommu_ops(iommu_group_first_dev(group));
struct iommu_domain *dom;
lockdep_assert_held(&group->mutex);
@@ -1853,7 +1851,7 @@ static int iommu_bus_notifier(struct notifier_block *nb,
static int iommu_get_def_domain_type(struct iommu_group *group,
struct device *dev, int cur_type)
{
- const struct iommu_ops *ops = group_iommu_ops(group);
+ const struct iommu_ops *ops = dev_iommu_ops(dev);
int type;
if (!ops->def_domain_type)
@@ -2020,7 +2018,7 @@ bool device_iommu_capable(struct device *dev, enum iommu_cap cap)
{
const struct iommu_ops *ops;
- if (!dev->iommu || !dev->iommu->iommu_dev)
+ if (!dev_has_iommu(dev))
return false;
ops = dev_iommu_ops(dev);
@@ -2117,11 +2115,9 @@ static struct iommu_domain *__iommu_domain_alloc(const struct iommu_ops *ops,
static struct iommu_domain *
__iommu_group_domain_alloc(struct iommu_group *group, unsigned int type)
{
- struct device *dev =
- list_first_entry(&group->devices, struct group_device, list)
- ->dev;
+ struct device *dev = iommu_group_first_dev(group);
- return __iommu_domain_alloc(group_iommu_ops(group), dev, type);
+ return __iommu_domain_alloc(dev_iommu_ops(dev), dev, type);
}
struct iommu_domain *iommu_domain_alloc(const struct bus_type *bus)
@@ -2972,8 +2968,8 @@ EXPORT_SYMBOL_GPL(iommu_fwspec_add_ids);
*/
int iommu_dev_enable_feature(struct device *dev, enum iommu_dev_features feat)
{
- if (dev->iommu && dev->iommu->iommu_dev) {
- const struct iommu_ops *ops = dev->iommu->iommu_dev->ops;
+ if (dev_has_iommu(dev)) {
+ const struct iommu_ops *ops = dev_iommu_ops(dev);
if (ops->dev_enable_feat)
return ops->dev_enable_feat(dev, feat);
@@ -2988,8 +2984,8 @@ EXPORT_SYMBOL_GPL(iommu_dev_enable_feature);
*/
int iommu_dev_disable_feature(struct device *dev, enum iommu_dev_features feat)
{
- if (dev->iommu && dev->iommu->iommu_dev) {
- const struct iommu_ops *ops = dev->iommu->iommu_dev->ops;
+ if (dev_has_iommu(dev)) {
+ const struct iommu_ops *ops = dev_iommu_ops(dev);
if (ops->dev_disable_feat)
return ops->dev_disable_feat(dev, feat);
--
2.39.2.101.g768bb238c484.dirty
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