[PATCH v3 1/7] iommu: Prevent pasid attach if no ops->remove_dev_pasid

[Yi Liu <yi.l.liu@intel.com>]

driver should implement both set_dev_pasid and remove_dev_pasid op, otherwise
it is a problem how to detach pasid. In reality, it is impossible that an
iommu driver implements set_dev_pasid() but no remove_dev_pasid() op. However,
it is better to check it.

Signed-off-by: Yi Liu <yi.l.liu@intel.com>
---
 drivers/iommu/iommu.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
index ea6b4a96186d..866559bbc4e4 100644
--- a/drivers/iommu/iommu.c
+++ b/drivers/iommu/iommu.c
@@ -3454,11 +3454,13 @@ int iommu_attach_device_pasid(struct iommu_domain *domain,
 			      struct iommu_attach_handle *handle)
 {
 	/* Caller must be a probed driver on dev */
+	const struct iommu_ops *ops = dev_iommu_ops(dev);
 	struct iommu_group *group = dev->iommu_group;
 	struct group_device *device;
 	int ret;
 
-	if (!domain->ops->set_dev_pasid)
+	if (!domain->ops->set_dev_pasid ||
+	    !ops->remove_dev_pasid)
 		return -EOPNOTSUPP;
 
 	if (!group)
-- 
2.34.1