Messages in this thread | | | Date | Thu, 10 Aug 2023 10:05:55 +0800 | Subject | Re: [PATCH v6 3/4] iommufd: Add IOMMU_GET_HW_INFO | From | Baolu Lu <> |
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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
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