| Message ID | a24acdd821a87ddab2ed4f5dc4e5ba047e126404.1694693889.git.robin.murphy@arm.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Iommu: Retire bus ops | expand |
On Fri, Sep 15, 2023 at 05:58:05PM +0100, Robin Murphy wrote: > 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@linux.intel.com> > Signed-off-by: Robin Murphy <robin.murphy@arm.com> > > --- > > v3: Rename dev_iommu_ops_valid() to reflect what it's actually checking, > rather than an implied consequence. > --- > drivers/iommu/iommu.c | 40 +++++++++++++++++++++++++--------------- > 1 file changed, 25 insertions(+), 15 deletions(-) > > diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c > index 3bfc56df4f78..4566d0001cd3 100644 > --- a/drivers/iommu/iommu.c > +++ b/drivers/iommu/iommu.c > @@ -363,6 +363,15 @@ 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; > +} After having gone through all the locking here, I'd prefer to err on the side of clearer documentation when it is actually safe to invoke this. I suggest /* Use in driver facing APIs, API must only be called by a probed driver */ static inline const struct iommu_ops *dev_maybe_iommu_ops(struct device *dev) { if (!dev->iommu || !dev->iommu_iommu_dev)) return NULL; return dev_iommu_ops(dev); } Since only this: > static u32 dev_iommu_get_max_pasids(struct device *dev) > { > u32 max_pasids = 0, bits = 0; > @@ -614,7 +623,7 @@ 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; Uses a different rule, and it is safe for some pretty unique reasons. The next patch doesn't follow these rules, I will add a note there.. > @@ -3190,21 +3203,18 @@ void iommu_device_unuse_default_domain(struct device *dev) > > static int __iommu_group_alloc_blocking_domain(struct iommu_group *group) > { > - struct group_device *dev = > - list_first_entry(&group->devices, struct group_device, list); > + struct device *dev = iommu_group_first_dev(group); > > if (group->blocking_domain) > return 0; > > - group->blocking_domain = > - __iommu_domain_alloc(dev->dev->bus, IOMMU_DOMAIN_BLOCKED); > + group->blocking_domain = __iommu_domain_alloc(dev->bus, IOMMU_DOMAIN_BLOCKED); > if (!group->blocking_domain) { > /* > * For drivers that do not yet understand IOMMU_DOMAIN_BLOCKED > * create an empty domain instead. > */ > - group->blocking_domain = __iommu_domain_alloc( > - dev->dev->bus, IOMMU_DOMAIN_UNMANAGED); > + group->blocking_domain = __iommu_domain_alloc(dev->bus, IOMMU_DOMAIN_UNMANAGED); > if (!group->blocking_domain) > return -EINVAL; > } My identity domain series fixed this up by adding __iommu_group_domain_alloc() Jason
diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c index 3bfc56df4f78..4566d0001cd3 100644 --- a/drivers/iommu/iommu.c +++ b/drivers/iommu/iommu.c @@ -363,6 +363,15 @@ 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; @@ -614,7 +623,7 @@ 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; @@ -1218,6 +1227,12 @@ 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 @@ -1745,9 +1760,7 @@ __iommu_group_alloc_default_domain(const struct bus_type *bus, static struct iommu_domain * iommu_group_alloc_default_domain(struct iommu_group *group, int req_type) { - const struct bus_type *bus = - list_first_entry(&group->devices, struct group_device, list) - ->dev->bus; + const struct bus_type *bus = iommu_group_first_dev(group)->bus; struct iommu_domain *dom; lockdep_assert_held(&group->mutex); @@ -1912,7 +1925,7 @@ 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); @@ -2903,8 +2916,8 @@ 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); @@ -2919,8 +2932,8 @@ 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); @@ -3190,21 +3203,18 @@ void iommu_device_unuse_default_domain(struct device *dev) static int __iommu_group_alloc_blocking_domain(struct iommu_group *group) { - struct group_device *dev = - list_first_entry(&group->devices, struct group_device, list); + struct device *dev = iommu_group_first_dev(group); if (group->blocking_domain) return 0; - group->blocking_domain = - __iommu_domain_alloc(dev->dev->bus, IOMMU_DOMAIN_BLOCKED); + group->blocking_domain = __iommu_domain_alloc(dev->bus, IOMMU_DOMAIN_BLOCKED); if (!group->blocking_domain) { /* * For drivers that do not yet understand IOMMU_DOMAIN_BLOCKED * create an empty domain instead. */ - group->blocking_domain = __iommu_domain_alloc( - dev->dev->bus, IOMMU_DOMAIN_UNMANAGED); + group->blocking_domain = __iommu_domain_alloc(dev->bus, IOMMU_DOMAIN_UNMANAGED); if (!group->blocking_domain) return -EINVAL; }