[PATCH v2 11/19] iommu: Add iommu_copy_struct_from_full_user_array helper

Nicolin Chen
2024-08-27T17:15:15Z

From: Jason Gunthorpe <jgg@nvidia.com>

The iommu_copy_struct_from_user_array helper can be used to copy a single
entry from a user array which might not be efficient if the array is big.

Add a new iommu_copy_struct_from_full_user_array to copy the entire user
array at once. Update the existing iommu_copy_struct_from_user_array kdoc
accordingly.

Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Signed-off-by: Nicolin Chen <nicolinc@nvidia.com>
---
include/linux/iommu.h | 49 ++++++++++++++++++++++++++++++++++++++++++-
1 file changed, 48 insertions(+), 1 deletion(-)

diff --git a/include/linux/iommu.h b/include/linux/iommu.h
index 8c1034cc3f7e..556b6d6cf2a8 100644
--- a/include/linux/iommu.h
+++ b/include/linux/iommu.h
@@ -493,7 +493,9 @@ static inline int __iommu_copy_struct_from_user_array(
* @index: Index to the location in the array to copy user data from
* @min_last: The last member of the data structure @kdst points in the
* initial version.
- * Return 0 for success, otherwise -error.
+ *
+ * Copy a single entry from a user array. Return 0 for success, otherwise
+ * -error.
*/
#define iommu_copy_struct_from_user_array(kdst, user_array, data_type, index, \
min_last) \
@@ -501,6 +503,51 @@ static inline int __iommu_copy_struct_from_user_array(
kdst, user_array, data_type, index, sizeof(*(kdst)), \
offsetofend(typeof(*(kdst)), min_last))

+
+/**
+ * iommu_copy_struct_from_full_user_array - Copy iommu driver specific user
+ * space data from an iommu_user_data_array
+ * @kdst: Pointer to an iommu driver specific user data that is defined in
+ * include/uapi/linux/iommufd.h
+ * @kdst_entry_size: sizeof(*kdst)
+ * @user_array: Pointer to a struct iommu_user_data_array for a user space
+ * array
+ * @data_type: The data type of the @kdst. Must match with @user_array->type
+ *
+ * Copy the entire user array. kdst must have room for kdst_entry_size *
+ * user_array->entry_num bytes. Return 0 for success, otherwise -error.
+ */
+static inline int
+iommu_copy_struct_from_full_user_array(void *kdst, size_t kdst_entry_size,
+ struct iommu_user_data_array *user_array,
+ unsigned int data_type)
+{
+ unsigned int i;
+ int ret;
+
+ if (user_array->type != data_type)
+ return -EINVAL;
+ if (!user_array->entry_num)
+ return -EINVAL;
+ if (likely(user_array->entry_len == kdst_entry_size)) {
+ if (copy_from_user(kdst, user_array->uptr,
+ user_array->entry_num *
+ user_array->entry_len))
+ return -EFAULT;
+ }
+
+ /* Copy item by item */
+ for (i = 0; i != user_array->entry_num; i++) {
+ ret = copy_struct_from_user(
+ kdst + kdst_entry_size * i, kdst_entry_size,
+ user_array->uptr + user_array->entry_len * i,
+ user_array->entry_len);
+ if (ret)
+ return ret;
+ }
+ return 0;
+}
+
/**
* struct iommu_ops - iommu ops and capabilities
* @capable: check capability
--
2.43.0