int retval = 0;
        unsigned long i, j;
        u64 paddr;
-       pgprot_t prot;
-       pte_t pte;
+       unsigned long prot;
        unsigned long vma_start = vma->vm_start;
        unsigned long vma_end = vma->vm_end;
        unsigned long vma_size = vma_end - vma_start;
 
        if (is_linear_pfn_mapping(vma)) {
                /*
-                * reserve the whole chunk starting from vm_pgoff,
-                * But, we have to get the protection from pte.
+                * reserve the whole chunk covered by vma. We need the
+                * starting address and protection from pte.
                 */
-               if (follow_pfnmap_pte(vma, vma_start, &pte)) {
+               if (follow_phys(vma, vma_start, 0, &prot, &paddr)) {
                        WARN_ON_ONCE(1);
-                       return -1;
+                       return -EINVAL;
                }
-               prot = pte_pgprot(pte);
-               paddr = (u64)vma->vm_pgoff << PAGE_SHIFT;
-               return reserve_pfn_range(paddr, vma_size, prot);
+               return reserve_pfn_range(paddr, vma_size, __pgprot(prot));
        }
 
        /* reserve entire vma page by page, using pfn and prot from pte */
        for (i = 0; i < vma_size; i += PAGE_SIZE) {
-               if (follow_pfnmap_pte(vma, vma_start + i, &pte))
+               if (follow_phys(vma, vma_start + i, 0, &prot, &paddr))
                        continue;
 
-               paddr = pte_pa(pte);
-               prot = pte_pgprot(pte);
-               retval = reserve_pfn_range(paddr, PAGE_SIZE, prot);
+               retval = reserve_pfn_range(paddr, PAGE_SIZE, __pgprot(prot));
                if (retval)
                        goto cleanup_ret;
        }
 cleanup_ret:
        /* Reserve error: Cleanup partial reservation and return error */
        for (j = 0; j < i; j += PAGE_SIZE) {
-               if (follow_pfnmap_pte(vma, vma_start + j, &pte))
+               if (follow_phys(vma, vma_start + j, 0, &prot, &paddr))
                        continue;
 
-               paddr = pte_pa(pte);
                free_pfn_range(paddr, PAGE_SIZE);
        }
 
 {
        unsigned long i;
        u64 paddr;
+       unsigned long prot;
        unsigned long vma_start = vma->vm_start;
        unsigned long vma_end = vma->vm_end;
        unsigned long vma_size = vma_end - vma_start;
        } else {
                /* free entire vma, page by page, using the pfn from pte */
                for (i = 0; i < vma_size; i += PAGE_SIZE) {
-                       pte_t pte;
-
-                       if (follow_pfnmap_pte(vma, vma_start + i, &pte))
+                       if (follow_phys(vma, vma_start + i, 0, &prot, &paddr))
                                continue;
 
-                       paddr = pte_pa(pte);
                        free_pfn_range(paddr, PAGE_SIZE);
                }
        }
 
        return page;
 }
 
-int follow_pfnmap_pte(struct vm_area_struct *vma, unsigned long address,
-                       pte_t *ret_ptep)
-{
-       pgd_t *pgd;
-       pud_t *pud;
-       pmd_t *pmd;
-       pte_t *ptep, pte;
-       spinlock_t *ptl;
-       struct page *page;
-       struct mm_struct *mm = vma->vm_mm;
-
-       if (!is_pfn_mapping(vma))
-               goto err;
-
-       page = NULL;
-       pgd = pgd_offset(mm, address);
-       if (pgd_none(*pgd) || unlikely(pgd_bad(*pgd)))
-               goto err;
-
-       pud = pud_offset(pgd, address);
-       if (pud_none(*pud) || unlikely(pud_bad(*pud)))
-               goto err;
-
-       pmd = pmd_offset(pud, address);
-       if (pmd_none(*pmd) || unlikely(pmd_bad(*pmd)))
-               goto err;
-
-       ptep = pte_offset_map_lock(mm, pmd, address, &ptl);
-
-       pte = *ptep;
-       if (!pte_present(pte))
-               goto err_unlock;
-
-       *ret_ptep = pte;
-       pte_unmap_unlock(ptep, ptl);
-       return 0;
-
-err_unlock:
-       pte_unmap_unlock(ptep, ptl);
-err:
-       return -EINVAL;
-}
-
 /* Can we do the FOLL_ANON optimization? */
 static inline int use_zero_page(struct vm_area_struct *vma)
 {