- pgd_t *pgd = pgd_offset(vma->vm_mm, addr);
- pmd_t *pmd;
- pte_t pte;
-
- if(pgd_none(*pgd))
- return 0;
-
- pmd = pmd_offset(pgd, addr);
- if(pmd_none(*pmd) || pmd_bad(*pmd))
- return 0;
-
- /* We cannot take the pte lock here: flush_cache_page is usually
- * called with pte lock already held. Whereas flush_dcache_page
- * takes flush_dcache_mmap_lock, which is lower in the hierarchy:
- * the vma itself is secure, but the pte might come or go racily.
- */
- pte = *pte_offset_map(pmd, addr);
- /* But pte_unmap() does nothing on this architecture */
-
- /* Filter out coincidental file entries and swap entries */
- if (!(pte_val(pte) & (_PAGE_FLUSH|_PAGE_PRESENT)))
- return 0;
-
- return pte_pfn(pte) == pfn;