On Thu, Jun 27, 2024 at 10:54:21AM +1000, Alistair Popple wrote:

+extern void prep_compound_page(struct page *page, unsigned int order);

No need for the extern.

 static int insert_page_into_pte_locked(struct vm_area_struct *vma, pte_t *pte,
-			unsigned long addr, struct page *page, pgprot_t prot)
+			unsigned long addr, struct page *page, pgprot_t prot, bool mkwrite)

Overly long line.

+	retval = insert_page_into_pte_locked(vma, pte, addr, page, prot, mkwrite);

.. same here.

+vm_fault_t dax_insert_pfn(struct vm_area_struct *vma,
+		unsigned long addr, pfn_t pfn_t, bool write)

This could probably use a kerneldoc comment.