On 2023/8/10 0:16, Jason Gunthorpe wrote:
On Wed, Aug 09, 2023 at 06:16:19PM +0800, Baolu Lu wrote:
On 2023/8/8 23:35, Yi Liu wrote:
+static int iommufd_fill_hw_info(struct device *dev, void __user *user_ptr,
+ unsigned int *length, u32 *type)
+{
+ const struct iommu_ops *ops;
+ unsigned int data_len;
+ void *data;
+ int rc = 0;
+
+ ops = dev_iommu_ops(dev);
+ if (!ops->hw_info) {
+ *length = 0;
+ *type = IOMMU_HW_INFO_TYPE_NONE;
+ return 0;
+ }
+
+ data = ops->hw_info(dev, &data_len, type);
+ if (IS_ERR(data))
+ return PTR_ERR(data);
+
+ /*
+ * drivers that have hw_info callback should have a unique
+ * iommu_hw_info_type.
+ */
+ if (WARN_ON_ONCE(*type == IOMMU_HW_INFO_TYPE_NONE)) {
+ rc = -ENODEV;
+ goto err_free;
+ }
+
+ *length = min(*length, data_len);
+ if (copy_to_user(user_ptr, data, *length)) {
copy_to_user() returns the number of bytes that were successfully
copied, right?
It returns length on failure and 0 on success
Then it's fine. Thanks for the explanation.
Best regards,
baolu
