On 6/4/26 05:26, Nicolin Chen wrote:
iommu_copy_struct_from_full_user_array() copies a whole user array into a kernel buffer. In the common case, where user entry_len equals destination entry size, it takes a fast path and copies the whole array with a single copy_from_user().That fast path does not return, so it falls through into the item-by-item copy_struct_from_user() loop and copies every entry a second time. For an equal entry_len that loop is just a copy_from_user() of the same bytes, so the whole array is copied twice for no benefit. Return right after the bulk copy. The per-item loop then runs only on the slow path, where entry_len differs and each entry needs size adaption. Fixes: 4f2e59ccb698 ("iommu: Add iommu_copy_struct_from_full_user_array helper") Assisted-by:Claude:claude-opus-4-8 Signed-off-by: Nicolin Chen<[email protected]> --- include/linux/iommu.h | 1 + 1 file changed, 1 insertion(+)
Reviewed-by: Lu Baolu <[email protected]>
