[v5,06/13] iommu: Add iommu_copy_struct_from_full_user_array helper

Commit Message

Nicolin Chen Oct. 25, 2024, 11:50 p.m. UTC

From: Jason Gunthorpe <[e-mail]>

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 <[e-mail]>
Signed-off-by: Nicolin Chen <[e-mail]>
---
 include/linux/iommu.h | 48 ++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 47 insertions(+), 1 deletion(-)

Comments

Tian, Kevin Oct. 29, 2024, 8:24 a.m. UTC | #1

> From: Nicolin Chen <[e-mail]>
> Sent: Saturday, October 26, 2024 7:51 AM
> 
> From: Jason Gunthorpe <[e-mail]>
> 
> 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.

what about:

iommu_copy_struct_from_user_array_single()
iommu_copy_struct_from_user_array_full()

?

> 
> Signed-off-by: Jason Gunthorpe <[e-mail]>
> Signed-off-by: Nicolin Chen <[e-mail]>

Reviewed-by: Kevin Tian <[e-mail]>

Nicolin Chen Oct. 30, 2024, 4:08 a.m. UTC | #2

On Tue, Oct 29, 2024 at 08:24:52AM +0000, Tian, Kevin wrote:
> > From: Nicolin Chen <[e-mail]>
> > Sent: Saturday, October 26, 2024 7:51 AM
> >
> > From: Jason Gunthorpe <[e-mail]>
> >
> > 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.
> 
> what about:
> 
> iommu_copy_struct_from_user_array_single()
> iommu_copy_struct_from_user_array_full()

I am okay with that, yet might prefer that in a separate patch? As
I am trying to reduce the number of changes in the series since we
are likely merging three series at once :)

Thanks
Nicolin

> > Signed-off-by: Jason Gunthorpe <[e-mail]>
> > Signed-off-by: Nicolin Chen <[e-mail]>
> 
> Reviewed-by: Kevin Tian <[e-mail]>

Patch

diff --git a/include/linux/iommu.h b/include/linux/iommu.h
index 14f24b5cd16f..3c3d5d0849d7 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 +503,50 @@  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