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Diffstat (limited to 'mm/page_vma_mapped.c')
-rw-r--r--mm/page_vma_mapped.c63
1 files changed, 38 insertions, 25 deletions
diff --git a/mm/page_vma_mapped.c b/mm/page_vma_mapped.c
index d22b84310f6d..956015614395 100644
--- a/mm/page_vma_mapped.c
+++ b/mm/page_vma_mapped.c
@@ -30,10 +30,29 @@ static bool map_pte(struct page_vma_mapped_walk *pvmw)
return true;
}
+/**
+ * check_pte - check if @pvmw->page is mapped at the @pvmw->pte
+ *
+ * page_vma_mapped_walk() found a place where @pvmw->page is *potentially*
+ * mapped. check_pte() has to validate this.
+ *
+ * @pvmw->pte may point to empty PTE, swap PTE or PTE pointing to arbitrary
+ * page.
+ *
+ * If PVMW_MIGRATION flag is set, returns true if @pvmw->pte contains migration
+ * entry that points to @pvmw->page or any subpage in case of THP.
+ *
+ * If PVMW_MIGRATION flag is not set, returns true if @pvmw->pte points to
+ * @pvmw->page or any subpage in case of THP.
+ *
+ * Otherwise, return false.
+ *
+ */
static bool check_pte(struct page_vma_mapped_walk *pvmw)
{
+ unsigned long pfn;
+
if (pvmw->flags & PVMW_MIGRATION) {
-#ifdef CONFIG_MIGRATION
swp_entry_t entry;
if (!is_swap_pte(*pvmw->pte))
return false;
@@ -41,37 +60,31 @@ static bool check_pte(struct page_vma_mapped_walk *pvmw)
if (!is_migration_entry(entry))
return false;
- if (migration_entry_to_page(entry) - pvmw->page >=
- hpage_nr_pages(pvmw->page)) {
- return false;
- }
- if (migration_entry_to_page(entry) < pvmw->page)
- return false;
-#else
- WARN_ON_ONCE(1);
-#endif
- } else {
- if (is_swap_pte(*pvmw->pte)) {
- swp_entry_t entry;
- entry = pte_to_swp_entry(*pvmw->pte);
- if (is_device_private_entry(entry) &&
- device_private_entry_to_page(entry) == pvmw->page)
- return true;
- }
+ pfn = migration_entry_to_pfn(entry);
+ } else if (is_swap_pte(*pvmw->pte)) {
+ swp_entry_t entry;
- if (!pte_present(*pvmw->pte))
+ /* Handle un-addressable ZONE_DEVICE memory */
+ entry = pte_to_swp_entry(*pvmw->pte);
+ if (!is_device_private_entry(entry))
return false;
- /* THP can be referenced by any subpage */
- if (pte_page(*pvmw->pte) - pvmw->page >=
- hpage_nr_pages(pvmw->page)) {
- return false;
- }
- if (pte_page(*pvmw->pte) < pvmw->page)
+ pfn = device_private_entry_to_pfn(entry);
+ } else {
+ if (!pte_present(*pvmw->pte))
return false;
+
+ pfn = pte_pfn(*pvmw->pte);
}
+ if (pfn < page_to_pfn(pvmw->page))
+ return false;
+
+ /* THP can be referenced by any subpage */
+ if (pfn - page_to_pfn(pvmw->page) >= hpage_nr_pages(pvmw->page))
+ return false;
+
return true;
}