10 Aug
2023
10 Aug
'23
2:05 a.m.
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