On 2023/9/21 15:51, Yi Liu wrote:
+/**
+ * iommu_copy_user_data - Copy iommu driver specific user space data
+ * @dst_data: Pointer to an iommu driver specific user data that is defined in
+ * include/uapi/linux/iommufd.h
+ * @src_data: Pointer to a struct iommu_user_data for user space data info
+ * @data_len: Length of current user data structure, i.e. sizeof(struct _dst)
+ * @min_len: Initial length of user data structure for backward compatibility.
+ * This should be offsetofend using the last member in the user data
+ * struct that was initially added to include/uapi/linux/iommufd.h
+ */
+static inline int iommu_copy_user_data(void *dst_data,
+ const struct iommu_user_data *src_data,
+ size_t data_len, size_t min_len)
+{
+ if (WARN_ON(!dst_data || !src_data))
+ return -EINVAL;
+ if (src_data->len < min_len || data_len < src_data->len)
+ return -EINVAL;
+ return copy_struct_from_user(dst_data, data_len,
+ src_data->uptr, src_data->len);
+}
I am not sure that I understand the purpose of "min_len" correctly. It
seems like it would always be equal to data_len?
Or, it means the minimal data length that the iommu driver requires?
Best regards,
baolu
