Provide individual device drivers the chance to gracefully refuse
to attach a device to the default domain. If the attach_device
op returns -ENOTSUPP don't print a error message and don't set
group->domain but still return success from iommu_group_add_dev().
This allows all the usual APIs to work and the next domain to try
to attach will take group->domain for itself and everything will
proceed as normal.
Signed-off-by: Jordan Crouse <jcro...@codeaurora.org>
---
drivers/iommu/iommu.c | 18 ++++++++++++++----
1 file changed, 14 insertions(+), 4 deletions(-)
diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
index 69fef991c651..2403cce138d2 100644
--- a/drivers/iommu/iommu.c
+++ b/drivers/iommu/iommu.c
@@ -592,7 +592,7 @@ int iommu_group_add_device(struct iommu_group *group,
struct device *dev)
if (group->domain)
ret = __iommu_attach_device(group->domain, dev);
mutex_unlock(&group->mutex);
- if (ret)
+ if (ret && ret != -ENOTSUPP)
goto err_put_group;
/* Notify any listeners about change to group. */
@@ -617,7 +617,9 @@ int iommu_group_add_device(struct iommu_group *group,
struct device *dev)
sysfs_remove_link(&dev->kobj, "iommu_group");
err_free_device:
kfree(device);
- pr_err("Failed to add device %s to group %d: %d\n", dev_name(dev),
group->id, ret);
+ if (ret != -ENOTSUPP)
+ pr_err("Failed to add device %s to group %d: %d\n",
+ dev_name(dev), group->id, ret);
return ret;
}
EXPORT_SYMBOL_GPL(iommu_group_add_device);
@@ -1039,8 +1041,16 @@ struct iommu_group *iommu_group_get_for_dev(struct
device *dev)
ret = iommu_group_add_device(group, dev);
if (ret) {
- iommu_group_put(group);
- return ERR_PTR(ret);
+ /*
+ * If the driver chooses not to bind the device, reset
+ * group->domain so a new domain can be added later
+ */
+ if (ret == -ENOTSUPP)
+ group->domain = NULL;
+ else {
+ iommu_group_put(group);
+ return ERR_PTR(ret);
+ }
}
return group;
--
2.16.1
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