diff --git a/Documentation/mm/page_owner.rst b/Documentation/mm/page_owner.rst
index f5c954afe97c..f18fd8907049 100644
--- a/Documentation/mm/page_owner.rst
+++ b/Documentation/mm/page_owner.rst
@@ -94,6 +94,11 @@ Usage
 	Page allocated via order XXX, ...
 	PFN XXX ...
 	// Detailed stack
+    By default, it will do full pfn dump, to start with a given pfn,
+    page_owner supports fseek.
+
+    FILE *fp = fopen("/sys/kernel/debug/page_owner", "r");
+    fseek(fp, pfn_start, SEEK_SET);
 
    The ``page_owner_sort`` tool ignores ``PFN`` rows, puts the remaining rows
    in buf, uses regexp to extract the page order value, counts the times
diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c
index e551433cd107..04077a2bb8a2 100644
--- a/drivers/block/zram/zram_drv.c
+++ b/drivers/block/zram/zram_drv.c
@@ -1710,9 +1710,6 @@ out:
 
 static void zram_reset_device(struct zram *zram)
 {
-	struct zcomp *comp;
-	u64 disksize;
-
 	down_write(&zram->init_lock);
 
 	zram->limit_pages = 0;
@@ -1722,17 +1719,15 @@ static void zram_reset_device(struct zram *zram)
 		return;
 	}
 
-	comp = zram->comp;
-	disksize = zram->disksize;
-	zram->disksize = 0;
-
 	set_capacity_and_notify(zram->disk, 0);
 	part_stat_set_all(zram->disk->part0, 0);
 
 	/* I/O operation under all of CPU are done so let's free */
-	zram_meta_free(zram, disksize);
+	zram_meta_free(zram, zram->disksize);
+	zram->disksize = 0;
 	memset(&zram->stats, 0, sizeof(zram->stats));
-	zcomp_destroy(comp);
+	zcomp_destroy(zram->comp);
+	zram->comp = NULL;
 	reset_bdev(zram);
 
 	up_write(&zram->init_lock);
diff --git a/include/linux/mm.h b/include/linux/mm.h
index 27839b158ca4..e98ef2cb1176 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -2520,7 +2520,6 @@ extern unsigned long absent_pages_in_range(unsigned long start_pfn,
 						unsigned long end_pfn);
 extern void get_pfn_range_for_nid(unsigned int nid,
 			unsigned long *start_pfn, unsigned long *end_pfn);
-extern unsigned long find_min_pfn_with_active_regions(void);
 
 #ifndef CONFIG_NUMA
 static inline int early_pfn_to_nid(unsigned long pfn)
diff --git a/include/linux/page_ext.h b/include/linux/page_ext.h
index fabb2e1e087f..ed27198cdaf4 100644
--- a/include/linux/page_ext.h
+++ b/include/linux/page_ext.h
@@ -55,7 +55,8 @@ static inline void page_ext_init(void)
 }
 #endif
 
-struct page_ext *lookup_page_ext(const struct page *page);
+extern struct page_ext *page_ext_get(struct page *page);
+extern void page_ext_put(struct page_ext *page_ext);
 
 static inline struct page_ext *page_ext_next(struct page_ext *curr)
 {
@@ -71,11 +72,6 @@ static inline void pgdat_page_ext_init(struct pglist_data *pgdat)
 {
 }
 
-static inline struct page_ext *lookup_page_ext(const struct page *page)
-{
-	return NULL;
-}
-
 static inline void page_ext_init(void)
 {
 }
@@ -87,5 +83,14 @@ static inline void page_ext_init_flatmem_late(void)
 static inline void page_ext_init_flatmem(void)
 {
 }
+
+static inline struct page_ext *page_ext_get(struct page *page)
+{
+	return NULL;
+}
+
+static inline void page_ext_put(struct page_ext *page_ext)
+{
+}
 #endif /* CONFIG_PAGE_EXTENSION */
 #endif /* __LINUX_PAGE_EXT_H */
diff --git a/include/linux/page_idle.h b/include/linux/page_idle.h
index 4663dfed1293..5cb7bd2078ec 100644
--- a/include/linux/page_idle.h
+++ b/include/linux/page_idle.h
@@ -13,65 +13,79 @@
  * If there is not enough space to store Idle and Young bits in page flags, use
  * page ext flags instead.
  */
-
 static inline bool folio_test_young(struct folio *folio)
 {
-	struct page_ext *page_ext = lookup_page_ext(&folio->page);
+	struct page_ext *page_ext = page_ext_get(&folio->page);
+	bool page_young;
 
 	if (unlikely(!page_ext))
 		return false;
 
-	return test_bit(PAGE_EXT_YOUNG, &page_ext->flags);
+	page_young = test_bit(PAGE_EXT_YOUNG, &page_ext->flags);
+	page_ext_put(page_ext);
+
+	return page_young;
 }
 
 static inline void folio_set_young(struct folio *folio)
 {
-	struct page_ext *page_ext = lookup_page_ext(&folio->page);
+	struct page_ext *page_ext = page_ext_get(&folio->page);
 
 	if (unlikely(!page_ext))
 		return;
 
 	set_bit(PAGE_EXT_YOUNG, &page_ext->flags);
+	page_ext_put(page_ext);
 }
 
 static inline bool folio_test_clear_young(struct folio *folio)
 {
-	struct page_ext *page_ext = lookup_page_ext(&folio->page);
+	struct page_ext *page_ext = page_ext_get(&folio->page);
+	bool page_young;
 
 	if (unlikely(!page_ext))
 		return false;
 
-	return test_and_clear_bit(PAGE_EXT_YOUNG, &page_ext->flags);
+	page_young = test_and_clear_bit(PAGE_EXT_YOUNG, &page_ext->flags);
+	page_ext_put(page_ext);
+
+	return page_young;
 }
 
 static inline bool folio_test_idle(struct folio *folio)
 {
-	struct page_ext *page_ext = lookup_page_ext(&folio->page);
+	struct page_ext *page_ext = page_ext_get(&folio->page);
+	bool page_idle;
 
 	if (unlikely(!page_ext))
 		return false;
 
-	return test_bit(PAGE_EXT_IDLE, &page_ext->flags);
+	page_idle =  test_bit(PAGE_EXT_IDLE, &page_ext->flags);
+	page_ext_put(page_ext);
+
+	return page_idle;
 }
 
 static inline void folio_set_idle(struct folio *folio)
 {
-	struct page_ext *page_ext = lookup_page_ext(&folio->page);
+	struct page_ext *page_ext = page_ext_get(&folio->page);
 
 	if (unlikely(!page_ext))
 		return;
 
 	set_bit(PAGE_EXT_IDLE, &page_ext->flags);
+	page_ext_put(page_ext);
 }
 
 static inline void folio_clear_idle(struct folio *folio)
 {
-	struct page_ext *page_ext = lookup_page_ext(&folio->page);
+	struct page_ext *page_ext = page_ext_get(&folio->page);
 
 	if (unlikely(!page_ext))
 		return;
 
 	clear_bit(PAGE_EXT_IDLE, &page_ext->flags);
+	page_ext_put(page_ext);
 }
 #endif /* !CONFIG_64BIT */
 
diff --git a/include/linux/pagewalk.h b/include/linux/pagewalk.h
index ac7b38ad5903..f3fafb731ffd 100644
--- a/include/linux/pagewalk.h
+++ b/include/linux/pagewalk.h
@@ -15,12 +15,12 @@ struct mm_walk;
  *			this handler is required to be able to handle
  *			pmd_trans_huge() pmds.  They may simply choose to
  *			split_huge_page() instead of handling it explicitly.
- * @pte_entry:		if set, called for each non-empty PTE (lowest-level)
- *			entry
+ * @pte_entry:		if set, called for each PTE (lowest-level) entry,
+ *			including empty ones
  * @pte_hole:		if set, called for each hole at all levels,
- *			depth is -1 if not known, 0:PGD, 1:P4D, 2:PUD, 3:PMD
- *			4:PTE. Any folded depths (where PTRS_PER_P?D is equal
- *			to 1) are skipped.
+ *			depth is -1 if not known, 0:PGD, 1:P4D, 2:PUD, 3:PMD.
+ *			Any folded depths (where PTRS_PER_P?D is equal to 1)
+ *			are skipped.
  * @hugetlb_entry:	if set, called for each hugetlb entry
  * @test_walk:		caller specific callback function to determine whether
  *			we walk over the current vma or not. Returning 0 means
diff --git a/mm/damon/vaddr.c b/mm/damon/vaddr.c
index 3c7b9d6dca95..cc04d467ba23 100644
--- a/mm/damon/vaddr.c
+++ b/mm/damon/vaddr.c
@@ -302,9 +302,14 @@ static int damon_mkold_pmd_entry(pmd_t *pmd, unsigned long addr,
 	pte_t *pte;
 	spinlock_t *ptl;
 
-	if (pmd_huge(*pmd)) {
+	if (pmd_trans_huge(*pmd)) {
 		ptl = pmd_lock(walk->mm, pmd);
-		if (pmd_huge(*pmd)) {
+		if (!pmd_present(*pmd)) {
+			spin_unlock(ptl);
+			return 0;
+		}
+
+		if (pmd_trans_huge(*pmd)) {
 			damon_pmdp_mkold(pmd, walk->mm, addr);
 			spin_unlock(ptl);
 			return 0;
@@ -429,9 +434,14 @@ static int damon_young_pmd_entry(pmd_t *pmd, unsigned long addr,
 	struct damon_young_walk_private *priv = walk->private;
 
 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
-	if (pmd_huge(*pmd)) {
+	if (pmd_trans_huge(*pmd)) {
 		ptl = pmd_lock(walk->mm, pmd);
-		if (!pmd_huge(*pmd)) {
+		if (!pmd_present(*pmd)) {
+			spin_unlock(ptl);
+			return 0;
+		}
+
+		if (!pmd_trans_huge(*pmd)) {
 			spin_unlock(ptl);
 			goto regular_page;
 		}
diff --git a/mm/gup.c b/mm/gup.c
index a88c86664026..9e9b17c42f3a 100644
--- a/mm/gup.c
+++ b/mm/gup.c
@@ -1927,20 +1927,16 @@ struct page *get_dump_page(unsigned long addr)
 
 #ifdef CONFIG_MIGRATION
 /*
- * Check whether all pages are pinnable. If some pages are not pinnable migrate
- * them and unpin all the pages. Returns -EAGAIN if pages were unpinned or zero
- * if all pages are pinnable and in the right zone. Other errors indicate
- * migration failure.
+ * Returns the number of collected pages. Return value is always >= 0.
  */
-static long check_and_migrate_movable_pages(unsigned long nr_pages,
-					    struct page **pages,
-					    unsigned int gup_flags)
+static unsigned long collect_longterm_unpinnable_pages(
+					struct list_head *movable_page_list,
+					unsigned long nr_pages,
+					struct page **pages)
 {
-	unsigned long i;
+	unsigned long i, collected = 0;
 	struct folio *prev_folio = NULL;
-	LIST_HEAD(movable_page_list);
-	bool drain_allow = true, coherent_pages = false;
-	int ret = 0;
+	bool drain_allow = true;
 
 	for (i = 0; i < nr_pages; i++) {
 		struct folio *folio = page_folio(pages[i]);
@@ -1949,45 +1945,16 @@ static long check_and_migrate_movable_pages(unsigned long nr_pages,
 			continue;
 		prev_folio = folio;
 
-		/*
-		 * Device coherent pages are managed by a driver and should not
-		 * be pinned indefinitely as it prevents the driver moving the
-		 * page. So when trying to pin with FOLL_LONGTERM instead try
-		 * to migrate the page out of device memory.
-		 */
-		if (folio_is_device_coherent(folio)) {
-			/*
-			 * We always want a new GUP lookup with device coherent
-			 * pages.
-			 */
-			pages[i] = 0;
-			coherent_pages = true;
-
-			/*
-			 * Migration will fail if the page is pinned, so convert
-			 * the pin on the source page to a normal reference.
-			 */
-			if (gup_flags & FOLL_PIN) {
-				get_page(&folio->page);
-				unpin_user_page(&folio->page);
-			}
-
-			if (migrate_device_coherent_page(&folio->page)) {
-				ret = -EBUSY;
-				break;
-			}
-			continue;
-		}
-
 		if (folio_is_longterm_pinnable(folio))
 			continue;
-		/*
-		 * Try to move out any movable page before pinning the range.
-		 */
+
+		collected++;
+
+		if (folio_is_device_coherent(folio))
+			continue;
+
 		if (folio_test_hugetlb(folio)) {
-			if (isolate_hugetlb(&folio->page,
-						&movable_page_list))
-				ret = -EBUSY;
+			isolate_hugetlb(&folio->page, movable_page_list);
 			continue;
 		}
 
@@ -1996,61 +1963,122 @@ static long check_and_migrate_movable_pages(unsigned long nr_pages,
 			drain_allow = false;
 		}
 
-		if (folio_isolate_lru(folio)) {
-			ret = -EBUSY;
+		if (!folio_isolate_lru(folio))
 			continue;
-		}
-		list_add_tail(&folio->lru, &movable_page_list);
+
+		list_add_tail(&folio->lru, movable_page_list);
 		node_stat_mod_folio(folio,
 				    NR_ISOLATED_ANON + folio_is_file_lru(folio),
 				    folio_nr_pages(folio));
 	}
 
-	/*
-	 * If list is empty, and no isolation errors, means that all pages are
-	 * in the correct zone. If there were device coherent pages some pages
-	 * have been unpinned.
-	 */
-	if (list_empty(&movable_page_list) && !ret && !coherent_pages)
-		return 0;
+	return collected;
+}
+
+/*
+ * Unpins all pages and migrates device coherent pages and movable_page_list.
+ * Returns -EAGAIN if all pages were successfully migrated or -errno for failure
+ * (or partial success).
+ */
+static int migrate_longterm_unpinnable_pages(
+					struct list_head *movable_page_list,
+					unsigned long nr_pages,
+					struct page **pages)
+{
+	int ret;
+	unsigned long i;
 
-	/*
-	 * Unpin all pages. If device coherent pages were found
-	 * migrate_device_coherent_page() will have dropped the pin and set
-	 * pages[i] == NULL.
-	 */
 	for (i = 0; i < nr_pages; i++) {
-		if (!pages[i])
-			continue;
+		struct folio *folio = page_folio(pages[i]);
 
-		if (gup_flags & FOLL_PIN)
-			unpin_user_page(pages[i]);
-		else
-			put_page(pages[i]);
+		if (folio_is_device_coherent(folio)) {
+			/*
+			 * Migration will fail if the page is pinned, so convert
+			 * the pin on the source page to a normal reference.
+			 */
+			pages[i] = NULL;
+			folio_get(folio);
+			gup_put_folio(folio, 1, FOLL_PIN);
+
+			if (migrate_device_coherent_page(&folio->page)) {
+				ret = -EBUSY;
+				goto err;
+			}
+
+			continue;
+		}
+
+		/*
+		 * We can't migrate pages with unexpected references, so drop
+		 * the reference obtained by __get_user_pages_locked().
+		 * Migrating pages have been added to movable_page_list after
+		 * calling folio_isolate_lru() which takes a reference so the
+		 * page won't be freed if it's migrating.
+		 */
+		unpin_user_page(pages[i]);
+		pages[i] = NULL;
 	}
 
-	if (!list_empty(&movable_page_list)) {
+	if (!list_empty(movable_page_list)) {
 		struct migration_target_control mtc = {
 			.nid = NUMA_NO_NODE,
 			.gfp_mask = GFP_USER | __GFP_NOWARN,
 		};
 
-		ret = migrate_pages(&movable_page_list, alloc_migration_target,
-				    NULL, (unsigned long)&mtc, MIGRATE_SYNC,
-				    MR_LONGTERM_PIN, NULL);
-		if (ret > 0) /* number of pages not migrated */
+		if (migrate_pages(movable_page_list, alloc_migration_target,
+				  NULL, (unsigned long)&mtc, MIGRATE_SYNC,
+				  MR_LONGTERM_PIN, NULL)) {
 			ret = -ENOMEM;
+			goto err;
+		}
 	}
 
-	if (ret && !list_empty(&movable_page_list))
-		putback_movable_pages(&movable_page_list);
+	putback_movable_pages(movable_page_list);
 
-	return ret ? ret : -EAGAIN;
+	return -EAGAIN;
+
+err:
+	for (i = 0; i < nr_pages; i++)
+		if (pages[i])
+			unpin_user_page(pages[i]);
+	putback_movable_pages(movable_page_list);
+
+	return ret;
+}
+
+/*
+ * Check whether all pages are *allowed* to be pinned. Rather confusingly, all
+ * pages in the range are required to be pinned via FOLL_PIN, before calling
+ * this routine.
+ *
+ * If any pages in the range are not allowed to be pinned, then this routine
+ * will migrate those pages away, unpin all the pages in the range and return
+ * -EAGAIN. The caller should re-pin the entire range with FOLL_PIN and then
+ * call this routine again.
+ *
+ * If an error other than -EAGAIN occurs, this indicates a migration failure.
+ * The caller should give up, and propagate the error back up the call stack.
+ *
+ * If everything is OK and all pages in the range are allowed to be pinned, then
+ * this routine leaves all pages pinned and returns zero for success.
+ */
+static long check_and_migrate_movable_pages(unsigned long nr_pages,
+					    struct page **pages)
+{
+	unsigned long collected;
+	LIST_HEAD(movable_page_list);
+
+	collected = collect_longterm_unpinnable_pages(&movable_page_list,
+						nr_pages, pages);
+	if (!collected)
+		return 0;
+
+	return migrate_longterm_unpinnable_pages(&movable_page_list, nr_pages,
+						pages);
 }
 #else
 static long check_and_migrate_movable_pages(unsigned long nr_pages,
-					    struct page **pages,
-					    unsigned int gup_flags)
+					    struct page **pages)
 {
 	return 0;
 }
@@ -2073,6 +2101,17 @@ static long __gup_longterm_locked(struct mm_struct *mm,
 	if (!(gup_flags & FOLL_LONGTERM))
 		return __get_user_pages_locked(mm, start, nr_pages, pages, vmas,
 					       NULL, gup_flags);
+
+	/*
+	 * If we get to this point then FOLL_LONGTERM is set, and FOLL_LONGTERM
+	 * implies FOLL_PIN (although the reverse is not true). Therefore it is
+	 * correct to unconditionally call check_and_migrate_movable_pages()
+	 * which assumes pages have been pinned via FOLL_PIN.
+	 *
+	 * Enforce the above reasoning by asserting that FOLL_PIN is set.
+	 */
+	if (WARN_ON(!(gup_flags & FOLL_PIN)))
+		return -EINVAL;
 	flags = memalloc_pin_save();
 	do {
 		nr_pinned_pages = __get_user_pages_locked(mm, start, nr_pages,
@@ -2082,8 +2121,7 @@ static long __gup_longterm_locked(struct mm_struct *mm,
 			rc = nr_pinned_pages;
 			break;
 		}
-		rc = check_and_migrate_movable_pages(nr_pinned_pages, pages,
-						     gup_flags);
+		rc = check_and_migrate_movable_pages(nr_pinned_pages, pages);
 	} while (rc == -EAGAIN);
 	memalloc_pin_restore(flags);
 
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index b6b9b0b8f847..ce025f95aa8c 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -770,8 +770,7 @@ static void set_huge_zero_page(pgtable_t pgtable, struct mm_struct *mm,
 		return;
 	entry = mk_pmd(zero_page, vma->vm_page_prot);
 	entry = pmd_mkhuge(entry);
-	if (pgtable)
-		pgtable_trans_huge_deposit(mm, pmd, pgtable);
+	pgtable_trans_huge_deposit(mm, pmd, pgtable);
 	set_pmd_at(mm, haddr, pmd, entry);
 	mm_inc_nr_ptes(mm);
 }
@@ -2644,6 +2643,8 @@ int split_huge_page_to_list(struct page *page, struct list_head *list)
 		mapping = NULL;
 		anon_vma_lock_write(anon_vma);
 	} else {
+		gfp_t gfp;
+
 		mapping = head->mapping;
 
 		/* Truncated ? */
@@ -2652,8 +2653,16 @@ int split_huge_page_to_list(struct page *page, struct list_head *list)
 			goto out;
 		}
 
-		xas_split_alloc(&xas, head, compound_order(head),
-				mapping_gfp_mask(mapping) & GFP_RECLAIM_MASK);
+		gfp = current_gfp_context(mapping_gfp_mask(mapping) &
+							GFP_RECLAIM_MASK);
+
+		if (folio_test_private(folio) &&
+				!filemap_release_folio(folio, gfp)) {
+			ret = -EBUSY;
+			goto out;
+		}
+
+		xas_split_alloc(&xas, head, compound_order(head), gfp);
 		if (xas_error(&xas)) {
 			ret = xas_error(&xas);
 			goto out;
diff --git a/mm/hugetlb_vmemmap.c b/mm/hugetlb_vmemmap.c
index 76b2d03a0d8d..ba2a2596fb4e 100644
--- a/mm/hugetlb_vmemmap.c
+++ b/mm/hugetlb_vmemmap.c
@@ -265,11 +265,10 @@ static void vmemmap_remap_pte(pte_t *pte, unsigned long addr,
 
 static inline void reset_struct_pages(struct page *start)
 {
-	int i;
 	struct page *from = start + NR_RESET_STRUCT_PAGE;
 
-	for (i = 0; i < NR_RESET_STRUCT_PAGE; i++)
-		memcpy(start + i, from, sizeof(*from));
+	BUILD_BUG_ON(NR_RESET_STRUCT_PAGE * 2 > PAGE_SIZE / sizeof(struct page));
+	memcpy(start, from, sizeof(*from) * NR_RESET_STRUCT_PAGE);
 }
 
 static void vmemmap_restore_pte(pte_t *pte, unsigned long addr,
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index bac2de4b9c42..29aeaf3d1915 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -1136,7 +1136,7 @@ static void invalidate_reclaim_iterators(struct mem_cgroup *dead_memcg)
 	} while ((memcg = parent_mem_cgroup(memcg)));
 
 	/*
-	 * When cgruop1 non-hierarchy mode is used,
+	 * When cgroup1 non-hierarchy mode is used,
 	 * parent_mem_cgroup() does not walk all the way up to the
 	 * cgroup root (root_mem_cgroup). So we have to handle
 	 * dead_memcg from cgroup root separately.
@@ -3969,6 +3969,8 @@ static const unsigned int memcg1_stats[] = {
 	NR_FILE_MAPPED,
 	NR_FILE_DIRTY,
 	NR_WRITEBACK,
+	WORKINGSET_REFAULT_ANON,
+	WORKINGSET_REFAULT_FILE,
 	MEMCG_SWAP,
 };
 
@@ -3982,6 +3984,8 @@ static const char *const memcg1_stat_names[] = {
 	"mapped_file",
 	"dirty",
 	"writeback",
+	"workingset_refault_anon",
+	"workingset_refault_file",
 	"swap",
 };
 
@@ -4010,7 +4014,8 @@ static int memcg_stat_show(struct seq_file *m, void *v)
 		if (memcg1_stats[i] == MEMCG_SWAP && !do_memsw_account())
 			continue;
 		nr = memcg_page_state_local(memcg, memcg1_stats[i]);
-		seq_printf(m, "%s %lu\n", memcg1_stat_names[i], nr * PAGE_SIZE);
+		seq_printf(m, "%s %lu\n", memcg1_stat_names[i],
+			   nr * memcg_page_state_unit(memcg1_stats[i]));
 	}
 
 	for (i = 0; i < ARRAY_SIZE(memcg1_events); i++)
@@ -4041,7 +4046,7 @@ static int memcg_stat_show(struct seq_file *m, void *v)
 			continue;
 		nr = memcg_page_state(memcg, memcg1_stats[i]);
 		seq_printf(m, "total_%s %llu\n", memcg1_stat_names[i],
-						(u64)nr * PAGE_SIZE);
+			   (u64)nr * memcg_page_state_unit(memcg1_stats[i]));
 	}
 
 	for (i = 0; i < ARRAY_SIZE(memcg1_events); i++)
diff --git a/mm/memory-failure.c b/mm/memory-failure.c
index e6713a979e42..265378237c22 100644
--- a/mm/memory-failure.c
+++ b/mm/memory-failure.c
@@ -413,7 +413,7 @@ static void kill_procs(struct list_head *to_kill, int forcekill, bool fail,
 {
 	struct to_kill *tk, *next;
 
-	list_for_each_entry_safe (tk, next, to_kill, nd) {
+	list_for_each_entry_safe(tk, next, to_kill, nd) {
 		if (forcekill) {
 			/*
 			 * In case something went wrong with munmapping
@@ -437,6 +437,7 @@ static void kill_procs(struct list_head *to_kill, int forcekill, bool fail,
 				pr_err("%#lx: Cannot send advisory machine check signal to %s:%d\n",
 				       pfn, tk->tsk->comm, tk->tsk->pid);
 		}
+		list_del(&tk->nd);
 		put_task_struct(tk->tsk);
 		kfree(tk);
 	}
@@ -1401,7 +1402,7 @@ static bool hwpoison_user_mappings(struct page *p, unsigned long pfn,
 	struct address_space *mapping;
 	LIST_HEAD(tokill);
 	bool unmap_success;
-	int kill = 1, forcekill;
+	int forcekill;
 	bool mlocked = PageMlocked(hpage);
 
 	/*
@@ -1442,7 +1443,6 @@ static bool hwpoison_user_mappings(struct page *p, unsigned long pfn,
 		if (page_mkclean(hpage)) {
 			SetPageDirty(hpage);
 		} else {
-			kill = 0;
 			ttu |= TTU_IGNORE_HWPOISON;
 			pr_info("%#lx: corrupted page was clean: dropped without side effects\n",
 				pfn);
@@ -1453,12 +1453,8 @@ static bool hwpoison_user_mappings(struct page *p, unsigned long pfn,
 	 * First collect all the processes that have the page
 	 * mapped in dirty form.  This has to be done before try_to_unmap,
 	 * because ttu takes the rmap data structures down.
-	 *
-	 * Error handling: We ignore errors here because
-	 * there's nothing that can be done.
 	 */
-	if (kill)
-		collect_procs(hpage, &tokill, flags & MF_ACTION_REQUIRED);
+	collect_procs(hpage, &tokill, flags & MF_ACTION_REQUIRED);
 
 	if (PageHuge(hpage) && !PageAnon(hpage)) {
 		/*
@@ -1500,7 +1496,8 @@ static bool hwpoison_user_mappings(struct page *p, unsigned long pfn,
 	 * use a more force-full uncatchable kill to prevent
 	 * any accesses to the poisoned memory.
 	 */
-	forcekill = PageDirty(hpage) || (flags & MF_MUST_KILL);
+	forcekill = PageDirty(hpage) || (flags & MF_MUST_KILL) ||
+		    !unmap_success;
 	kill_procs(&tokill, forcekill, !unmap_success, pfn, flags);
 
 	return unmap_success;
@@ -1865,8 +1862,10 @@ retry:
 
 	if (hwpoison_filter(p)) {
 		hugetlb_clear_page_hwpoison(head);
-		res = -EOPNOTSUPP;
-		goto out;
+		unlock_page(head);
+		if (res == 1)
+			put_page(head);
+		return -EOPNOTSUPP;
 	}
 
 	/*
@@ -2357,7 +2356,7 @@ int unpoison_memory(unsigned long pfn)
 		goto unlock_mutex;
 	}
 
-	if (PageSlab(page) || PageTable(page))
+	if (PageSlab(page) || PageTable(page) || PageReserved(page))
 		goto unlock_mutex;
 
 	ret = get_hwpoison_page(p, MF_UNPOISON);
@@ -2381,13 +2380,14 @@ int unpoison_memory(unsigned long pfn)
 			count = free_raw_hwp_pages(page, false);
 			if (count == 0) {
 				ret = -EBUSY;
+				put_page(page);
 				goto unlock_mutex;
 			}
 		}
 		freeit = !!TestClearPageHWPoison(p);
 
 		put_page(page);
-		if (freeit && !(pfn == my_zero_pfn(0) && page_count(p) == 1)) {
+		if (freeit) {
 			put_page(page);
 			ret = 0;
 		}
@@ -2437,11 +2437,11 @@ static bool isolate_page(struct page *page, struct list_head *pagelist)
 }
 
 /*
- * __soft_offline_page handles hugetlb-pages and non-hugetlb pages.
+ * soft_offline_in_use_page handles hugetlb-pages and non-hugetlb pages.
  * If the page is a non-dirty unmapped page-cache page, it simply invalidates.
  * If the page is mapped, it migrates the contents over.
  */
-static int __soft_offline_page(struct page *page)
+static int soft_offline_in_use_page(struct page *page)
 {
 	long ret = 0;
 	unsigned long pfn = page_to_pfn(page);
@@ -2454,6 +2454,14 @@ static int __soft_offline_page(struct page *page)
 		.gfp_mask = GFP_USER | __GFP_MOVABLE | __GFP_RETRY_MAYFAIL,
 	};
 
+	if (!huge && PageTransHuge(hpage)) {
+		if (try_to_split_thp_page(page)) {
+			pr_info("soft offline: %#lx: thp split failed\n", pfn);
+			return -EBUSY;
+		}
+		hpage = page;
+	}
+
 	lock_page(page);
 	if (!PageHuge(page))
 		wait_on_page_writeback(page);
@@ -2503,29 +2511,6 @@ static int __soft_offline_page(struct page *page)
 	return ret;
 }
 
-static int soft_offline_in_use_page(struct page *page)
-{
-	struct page *hpage = compound_head(page);
-
-	if (!PageHuge(page) && PageTransHuge(hpage))
-		if (try_to_split_thp_page(page) < 0) {
-			pr_info("soft offline: %#lx: thp split failed\n",
-				page_to_pfn(page));
-			return -EBUSY;
-		}
-	return __soft_offline_page(page);
-}
-
-static int soft_offline_free_page(struct page *page)
-{
-	int rc = 0;
-
-	if (!page_handle_poison(page, true, false))
-		rc = -EBUSY;
-
-	return rc;
-}
-
 static void put_ref_page(struct page *page)
 {
 	if (page)
@@ -2593,8 +2578,6 @@ retry:
 	if (hwpoison_filter(page)) {
 		if (ret > 0)
 			put_page(page);
-		else
-			put_ref_page(ref_page);
 
 		mutex_unlock(&mf_mutex);
 		return -EOPNOTSUPP;
@@ -2603,7 +2586,7 @@ retry:
 	if (ret > 0) {
 		ret = soft_offline_in_use_page(page);
 	} else if (ret == 0) {
-		if (soft_offline_free_page(page) && try_again) {
+		if (!page_handle_poison(page, true, false) && try_again) {
 			try_again = false;
 			flags &= ~MF_COUNT_INCREASED;
 			goto retry;
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 7e16873b4b6f..ba0b438d57ab 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -7957,17 +7957,6 @@ unsigned long __init node_map_pfn_alignment(void)
 	return ~accl_mask + 1;
 }
 
-/**
- * find_min_pfn_with_active_regions - Find the minimum PFN registered
- *
- * Return: the minimum PFN based on information provided via
- * memblock_set_node().
- */
-unsigned long __init find_min_pfn_with_active_regions(void)
-{
-	return PHYS_PFN(memblock_start_of_DRAM());
-}
-
 /*
  * early_calculate_totalpages()
  * Sum pages in active regions for movable zone.
@@ -8260,7 +8249,7 @@ void __init free_area_init(unsigned long *max_zone_pfn)
 	memset(arch_zone_highest_possible_pfn, 0,
 				sizeof(arch_zone_highest_possible_pfn));
 
-	start_pfn = find_min_pfn_with_active_regions();
+	start_pfn = PHYS_PFN(memblock_start_of_DRAM());
 	descending = arch_has_descending_max_zone_pfns();
 
 	for (i = 0; i < MAX_NR_ZONES; i++) {
diff --git a/mm/page_counter.c b/mm/page_counter.c
index eb156ff5d603..8a0cc24b60dd 100644
--- a/mm/page_counter.c
+++ b/mm/page_counter.c
@@ -193,7 +193,7 @@ int page_counter_set_max(struct page_counter *counter, unsigned long nr_pages)
 
 		old = xchg(&counter->max, nr_pages);
 
-		if (page_counter_read(counter) <= usage)
+		if (page_counter_read(counter) <= usage || nr_pages >= old)
 			return 0;
 
 		counter->max = old;
diff --git a/mm/page_ext.c b/mm/page_ext.c
index e22a928dd66a..b236bdd59fa8 100644
--- a/mm/page_ext.c
+++ b/mm/page_ext.c
@@ -9,6 +9,7 @@
 #include <linux/page_owner.h>
 #include <linux/page_idle.h>
 #include <linux/page_table_check.h>
+#include <linux/rcupdate.h>
 
 /*
  * struct page extension
@@ -59,6 +60,10 @@
  * can utilize this callback to initialize the state of it correctly.
  */
 
+#ifdef CONFIG_SPARSEMEM
+#define PAGE_EXT_INVALID       (0x1)
+#endif
+
 #if defined(CONFIG_PAGE_IDLE_FLAG) && !defined(CONFIG_64BIT)
 static bool need_page_idle(void)
 {
@@ -84,6 +89,7 @@ static struct page_ext_operations *page_ext_ops[] __initdata = {
 unsigned long page_ext_size = sizeof(struct page_ext);
 
 static unsigned long total_usage;
+static struct page_ext *lookup_page_ext(const struct page *page);
 
 static bool __init invoke_need_callbacks(void)
 {
@@ -125,6 +131,48 @@ static inline struct page_ext *get_entry(void *base, unsigned long index)
 	return base + page_ext_size * index;
 }
 
+/**
+ * page_ext_get() - Get the extended information for a page.
+ * @page: The page we're interested in.
+ *
+ * Ensures that the page_ext will remain valid until page_ext_put()
+ * is called.
+ *
+ * Return: NULL if no page_ext exists for this page.
+ * Context: Any context.  Caller may not sleep until they have called
+ * page_ext_put().
+ */
+struct page_ext *page_ext_get(struct page *page)
+{
+	struct page_ext *page_ext;
+
+	rcu_read_lock();
+	page_ext = lookup_page_ext(page);
+	if (!page_ext) {
+		rcu_read_unlock();
+		return NULL;
+	}
+
+	return page_ext;
+}
+
+/**
+ * page_ext_put() - Working with page extended information is done.
+ * @page_ext - Page extended information received from page_ext_get().
+ *
+ * The page extended information of the page may not be valid after this
+ * function is called.
+ *
+ * Return: None.
+ * Context: Any context with corresponding page_ext_get() is called.
+ */
+void page_ext_put(struct page_ext *page_ext)
+{
+	if (unlikely(!page_ext))
+		return;
+
+	rcu_read_unlock();
+}
 #ifndef CONFIG_SPARSEMEM
 
 
@@ -133,12 +181,13 @@ void __meminit pgdat_page_ext_init(struct pglist_data *pgdat)
 	pgdat->node_page_ext = NULL;
 }
 
-struct page_ext *lookup_page_ext(const struct page *page)
+static struct page_ext *lookup_page_ext(const struct page *page)
 {
 	unsigned long pfn = page_to_pfn(page);
 	unsigned long index;
 	struct page_ext *base;
 
+	WARN_ON_ONCE(!rcu_read_lock_held());
 	base = NODE_DATA(page_to_nid(page))->node_page_ext;
 	/*
 	 * The sanity checks the page allocator does upon freeing a
@@ -206,20 +255,27 @@ fail:
 }
 
 #else /* CONFIG_SPARSEMEM */
+static bool page_ext_invalid(struct page_ext *page_ext)
+{
+	return !page_ext || (((unsigned long)page_ext & PAGE_EXT_INVALID) == PAGE_EXT_INVALID);
+}
 
-struct page_ext *lookup_page_ext(const struct page *page)
+static struct page_ext *lookup_page_ext(const struct page *page)
 {
 	unsigned long pfn = page_to_pfn(page);
 	struct mem_section *section = __pfn_to_section(pfn);
+	struct page_ext *page_ext = READ_ONCE(section->page_ext);
+
+	WARN_ON_ONCE(!rcu_read_lock_held());
 	/*
 	 * The sanity checks the page allocator does upon freeing a
 	 * page can reach here before the page_ext arrays are
 	 * allocated when feeding a range of pages to the allocator
 	 * for the first time during bootup or memory hotplug.
 	 */
-	if (!section->page_ext)
+	if (page_ext_invalid(page_ext))
 		return NULL;
-	return get_entry(section->page_ext, pfn);
+	return get_entry(page_ext, pfn);
 }
 
 static void *__meminit alloc_page_ext(size_t size, int nid)
@@ -298,9 +354,30 @@ static void __free_page_ext(unsigned long pfn)
 	ms = __pfn_to_section(pfn);
 	if (!ms || !ms->page_ext)
 		return;
-	base = get_entry(ms->page_ext, pfn);
+
+	base = READ_ONCE(ms->page_ext);
+	/*
+	 * page_ext here can be valid while doing the roll back
+	 * operation in online_page_ext().
+	 */
+	if (page_ext_invalid(base))
+		base = (void *)base - PAGE_EXT_INVALID;
+	WRITE_ONCE(ms->page_ext, NULL);
+
+	base = get_entry(base, pfn);
 	free_page_ext(base);
-	ms->page_ext = NULL;
+}
+
+static void __invalidate_page_ext(unsigned long pfn)
+{
+	struct mem_section *ms;
+	void *val;
+
+	ms = __pfn_to_section(pfn);
+	if (!ms || !ms->page_ext)
+		return;
+	val = (void *)ms->page_ext + PAGE_EXT_INVALID;
+	WRITE_ONCE(ms->page_ext, val);
 }
 
 static int __meminit online_page_ext(unsigned long start_pfn,
@@ -343,6 +420,20 @@ static int __meminit offline_page_ext(unsigned long start_pfn,
 	start = SECTION_ALIGN_DOWN(start_pfn);
 	end = SECTION_ALIGN_UP(start_pfn + nr_pages);
 
+	/*
+	 * Freeing of page_ext is done in 3 steps to avoid
+	 * use-after-free of it:
+	 * 1) Traverse all the sections and mark their page_ext
+	 *    as invalid.
+	 * 2) Wait for all the existing users of page_ext who
+	 *    started before invalidation to finish.
+	 * 3) Free the page_ext.
+	 */
+	for (pfn = start; pfn < end; pfn += PAGES_PER_SECTION)
+		__invalidate_page_ext(pfn);
+
+	synchronize_rcu();
+
 	for (pfn = start; pfn < end; pfn += PAGES_PER_SECTION)
 		__free_page_ext(pfn);
 	return 0;
diff --git a/mm/page_owner.c b/mm/page_owner.c
index e4c6f3f1695b..90023f938c19 100644
--- a/mm/page_owner.c
+++ b/mm/page_owner.c
@@ -141,7 +141,7 @@ void __reset_page_owner(struct page *page, unsigned short order)
 	struct page_owner *page_owner;
 	u64 free_ts_nsec = local_clock();
 
-	page_ext = lookup_page_ext(page);
+	page_ext = page_ext_get(page);
 	if (unlikely(!page_ext))
 		return;
 
@@ -153,6 +153,7 @@ void __reset_page_owner(struct page *page, unsigned short order)
 		page_owner->free_ts_nsec = free_ts_nsec;
 		page_ext = page_ext_next(page_ext);
 	}
+	page_ext_put(page_ext);
 }
 
 static inline void __set_page_owner_handle(struct page_ext *page_ext,
@@ -183,19 +184,21 @@ static inline void __set_page_owner_handle(struct page_ext *page_ext,
 noinline void __set_page_owner(struct page *page, unsigned short order,
 					gfp_t gfp_mask)
 {
-	struct page_ext *page_ext = lookup_page_ext(page);
+	struct page_ext *page_ext;
 	depot_stack_handle_t handle;
 
+	handle = save_stack(gfp_mask);
+
+	page_ext = page_ext_get(page);
 	if (unlikely(!page_ext))
 		return;
-
-	handle = save_stack(gfp_mask);
 	__set_page_owner_handle(page_ext, handle, order, gfp_mask);
+	page_ext_put(page_ext);
 }
 
 void __set_page_owner_migrate_reason(struct page *page, int reason)
 {
-	struct page_ext *page_ext = lookup_page_ext(page);
+	struct page_ext *page_ext = page_ext_get(page);
 	struct page_owner *page_owner;
 
 	if (unlikely(!page_ext))
@@ -203,12 +206,13 @@ void __set_page_owner_migrate_reason(struct page *page, int reason)
 
 	page_owner = get_page_owner(page_ext);
 	page_owner->last_migrate_reason = reason;
+	page_ext_put(page_ext);
 }
 
 void __split_page_owner(struct page *page, unsigned int nr)
 {
 	int i;
-	struct page_ext *page_ext = lookup_page_ext(page);
+	struct page_ext *page_ext = page_ext_get(page);
 	struct page_owner *page_owner;
 
 	if (unlikely(!page_ext))
@@ -219,17 +223,25 @@ void __split_page_owner(struct page *page, unsigned int nr)
 		page_owner->order = 0;
 		page_ext = page_ext_next(page_ext);
 	}
+	page_ext_put(page_ext);
 }
 
 void __folio_copy_owner(struct folio *newfolio, struct folio *old)
 {
-	struct page_ext *old_ext = lookup_page_ext(&old->page);
-	struct page_ext *new_ext = lookup_page_ext(&newfolio->page);
+	struct page_ext *old_ext;
+	struct page_ext *new_ext;
 	struct page_owner *old_page_owner, *new_page_owner;
 
-	if (unlikely(!old_ext || !new_ext))
+	old_ext = page_ext_get(&old->page);
+	if (unlikely(!old_ext))
 		return;
 
+	new_ext = page_ext_get(&newfolio->page);
+	if (unlikely(!new_ext)) {
+		page_ext_put(old_ext);
+		return;
+	}
+
 	old_page_owner = get_page_owner(old_ext);
 	new_page_owner = get_page_owner(new_ext);
 	new_page_owner->order = old_page_owner->order;
@@ -254,6 +266,8 @@ void __folio_copy_owner(struct folio *newfolio, struct folio *old)
 	 */
 	__set_bit(PAGE_EXT_OWNER, &new_ext->flags);
 	__set_bit(PAGE_EXT_OWNER_ALLOCATED, &new_ext->flags);
+	page_ext_put(new_ext);
+	page_ext_put(old_ext);
 }
 
 void pagetypeinfo_showmixedcount_print(struct seq_file *m,
@@ -307,12 +321,12 @@ void pagetypeinfo_showmixedcount_print(struct seq_file *m,
 			if (PageReserved(page))
 				continue;
 
-			page_ext = lookup_page_ext(page);
+			page_ext = page_ext_get(page);
 			if (unlikely(!page_ext))
 				continue;
 
 			if (!test_bit(PAGE_EXT_OWNER_ALLOCATED, &page_ext->flags))
-				continue;
+				goto ext_put_continue;
 
 			page_owner = get_page_owner(page_ext);
 			page_mt = gfp_migratetype(page_owner->gfp_mask);
@@ -323,9 +337,12 @@ void pagetypeinfo_showmixedcount_print(struct seq_file *m,
 					count[pageblock_mt]++;
 
 				pfn = block_end_pfn;
+				page_ext_put(page_ext);
 				break;
 			}
 			pfn += (1UL << page_owner->order) - 1;
+ext_put_continue:
+			page_ext_put(page_ext);
 		}
 	}
 
@@ -435,7 +452,7 @@ err:
 
 void __dump_page_owner(const struct page *page)
 {
-	struct page_ext *page_ext = lookup_page_ext(page);
+	struct page_ext *page_ext = page_ext_get((void *)page);
 	struct page_owner *page_owner;
 	depot_stack_handle_t handle;
 	gfp_t gfp_mask;
@@ -452,6 +469,7 @@ void __dump_page_owner(const struct page *page)
 
 	if (!test_bit(PAGE_EXT_OWNER, &page_ext->flags)) {
 		pr_alert("page_owner info is not present (never set?)\n");
+		page_ext_put(page_ext);
 		return;
 	}
 
@@ -482,6 +500,7 @@ void __dump_page_owner(const struct page *page)
 	if (page_owner->last_migrate_reason != -1)
 		pr_alert("page has been migrated, last migrate reason: %s\n",
 			migrate_reason_names[page_owner->last_migrate_reason]);
+	page_ext_put(page_ext);
 }
 
 static ssize_t
@@ -497,8 +516,10 @@ read_page_owner(struct file *file, char __user *buf, size_t count, loff_t *ppos)
 		return -EINVAL;
 
 	page = NULL;
-	pfn = min_low_pfn + *ppos;
-
+	if (*ppos == 0)
+		pfn = min_low_pfn;
+	else
+		pfn = *ppos;
 	/* Find a valid PFN or the start of a MAX_ORDER_NR_PAGES area */
 	while (!pfn_valid(pfn) && (pfn & (MAX_ORDER_NR_PAGES - 1)) != 0)
 		pfn++;
@@ -507,6 +528,14 @@ read_page_owner(struct file *file, char __user *buf, size_t count, loff_t *ppos)
 
 	/* Find an allocated page */
 	for (; pfn < max_pfn; pfn++) {
+		/*
+		 * This temporary page_owner is required so
+		 * that we can avoid the context switches while holding
+		 * the rcu lock and copying the page owner information to
+		 * user through copy_to_user() or GFP_KERNEL allocations.
+		 */
+		struct page_owner page_owner_tmp;
+
 		/*
 		 * If the new page is in a new MAX_ORDER_NR_PAGES area,
 		 * validate the area as existing, skip it if not
@@ -525,7 +554,7 @@ read_page_owner(struct file *file, char __user *buf, size_t count, loff_t *ppos)
 			continue;
 		}
 
-		page_ext = lookup_page_ext(page);
+		page_ext = page_ext_get(page);
 		if (unlikely(!page_ext))
 			continue;
 
@@ -534,14 +563,14 @@ read_page_owner(struct file *file, char __user *buf, size_t count, loff_t *ppos)
 		 * because we don't hold the zone lock.
 		 */
 		if (!test_bit(PAGE_EXT_OWNER, &page_ext->flags))
-			continue;
+			goto ext_put_continue;
 
 		/*
 		 * Although we do have the info about past allocation of free
 		 * pages, it's not relevant for current memory usage.
 		 */
 		if (!test_bit(PAGE_EXT_OWNER_ALLOCATED, &page_ext->flags))
-			continue;
+			goto ext_put_continue;
 
 		page_owner = get_page_owner(page_ext);
 
@@ -550,7 +579,7 @@ read_page_owner(struct file *file, char __user *buf, size_t count, loff_t *ppos)
 		 * would inflate the stats.
 		 */
 		if (!IS_ALIGNED(pfn, 1 << page_owner->order))
-			continue;
+			goto ext_put_continue;
 
 		/*
 		 * Access to page_ext->handle isn't synchronous so we should
@@ -558,18 +587,37 @@ read_page_owner(struct file *file, char __user *buf, size_t count, loff_t *ppos)
 		 */
 		handle = READ_ONCE(page_owner->handle);
 		if (!handle)
-			continue;
+			goto ext_put_continue;
 
 		/* Record the next PFN to read in the file offset */
-		*ppos = (pfn - min_low_pfn) + 1;
+		*ppos = pfn + 1;
 
+		page_owner_tmp = *page_owner;
+		page_ext_put(page_ext);
 		return print_page_owner(buf, count, pfn, page,
-				page_owner, handle);
+				&page_owner_tmp, handle);
+ext_put_continue:
+		page_ext_put(page_ext);
 	}
 
 	return 0;
 }
 
+static loff_t lseek_page_owner(struct file *file, loff_t offset, int orig)
+{
+	switch (orig) {
+	case SEEK_SET:
+		file->f_pos = offset;
+		break;
+	case SEEK_CUR:
+		file->f_pos += offset;
+		break;
+	default:
+		return -EINVAL;
+	}
+	return file->f_pos;
+}
+
 static void init_pages_in_zone(pg_data_t *pgdat, struct zone *zone)
 {
 	unsigned long pfn = zone->zone_start_pfn;
@@ -617,18 +665,20 @@ static void init_pages_in_zone(pg_data_t *pgdat, struct zone *zone)
 			if (PageReserved(page))
 				continue;
 
-			page_ext = lookup_page_ext(page);
+			page_ext = page_ext_get(page);
 			if (unlikely(!page_ext))
 				continue;
 
 			/* Maybe overlapping zone */
 			if (test_bit(PAGE_EXT_OWNER, &page_ext->flags))
-				continue;
+				goto ext_put_continue;
 
 			/* Found early allocated page */
 			__set_page_owner_handle(page_ext, early_handle,
 						0, 0);
 			count++;
+ext_put_continue:
+			page_ext_put(page_ext);
 		}
 		cond_resched();
 	}
@@ -660,6 +710,7 @@ static void init_early_allocated_pages(void)
 
 static const struct file_operations proc_page_owner_operations = {
 	.read		= read_page_owner,
+	.llseek		= lseek_page_owner,
 };
 
 static int __init pageowner_init(void)
diff --git a/mm/page_table_check.c b/mm/page_table_check.c
index e2062748791a..903db62794d3 100644
--- a/mm/page_table_check.c
+++ b/mm/page_table_check.c
@@ -68,7 +68,7 @@ static void page_table_check_clear(struct mm_struct *mm, unsigned long addr,
 		return;
 
 	page = pfn_to_page(pfn);
-	page_ext = lookup_page_ext(page);
+	page_ext = page_ext_get(page);
 	anon = PageAnon(page);
 
 	for (i = 0; i < pgcnt; i++) {
@@ -83,6 +83,7 @@ static void page_table_check_clear(struct mm_struct *mm, unsigned long addr,
 		}
 		page_ext = page_ext_next(page_ext);
 	}
+	page_ext_put(page_ext);
 }
 
 /*
@@ -103,7 +104,7 @@ static void page_table_check_set(struct mm_struct *mm, unsigned long addr,
 		return;
 
 	page = pfn_to_page(pfn);
-	page_ext = lookup_page_ext(page);
+	page_ext = page_ext_get(page);
 	anon = PageAnon(page);
 
 	for (i = 0; i < pgcnt; i++) {
@@ -118,6 +119,7 @@ static void page_table_check_set(struct mm_struct *mm, unsigned long addr,
 		}
 		page_ext = page_ext_next(page_ext);
 	}
+	page_ext_put(page_ext);
 }
 
 /*
@@ -126,9 +128,10 @@ static void page_table_check_set(struct mm_struct *mm, unsigned long addr,
  */
 void __page_table_check_zero(struct page *page, unsigned int order)
 {
-	struct page_ext *page_ext = lookup_page_ext(page);
+	struct page_ext *page_ext;
 	unsigned long i;
 
+	page_ext = page_ext_get(page);
 	BUG_ON(!page_ext);
 	for (i = 0; i < (1ul << order); i++) {
 		struct page_table_check *ptc = get_page_table_check(page_ext);
@@ -137,6 +140,7 @@ void __page_table_check_zero(struct page *page, unsigned int order)
 		BUG_ON(atomic_read(&ptc->file_map_count));
 		page_ext = page_ext_next(page_ext);
 	}
+	page_ext_put(page_ext);
 }
 
 void __page_table_check_pte_clear(struct mm_struct *mm, unsigned long addr,
diff --git a/mm/pagewalk.c b/mm/pagewalk.c
index fa7a3d21a751..1cb8de5889c4 100644
--- a/mm/pagewalk.c
+++ b/mm/pagewalk.c
@@ -482,7 +482,15 @@ int walk_page_range(struct mm_struct *mm, unsigned long start,
 	return err;
 }
 
-/*
+/**
+ * walk_page_range_novma - walk a range of pagetables not backed by a vma
+ * @mm:		mm_struct representing the target process of page table walk
+ * @start:	start address of the virtual address range
+ * @end:	end address of the virtual address range
+ * @ops:	operation to call during the walk
+ * @pgd:	pgd to walk if different from mm->pgd
+ * @private:	private data for callbacks' usage
+ *
  * Similar to walk_page_range() but can walk any page tables even if they are
  * not backed by VMAs. Because 'unusual' entries may be walked this function
  * will also not lock the PTEs for the pte_entry() callback. This is useful for
diff --git a/mm/vmalloc.c b/mm/vmalloc.c
index dd6cdb201195..e68c0081e861 100644
--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -590,7 +590,7 @@ int vmap_pages_range_noflush(unsigned long addr, unsigned long end,
 		int err;
 
 		err = vmap_range_noflush(addr, addr + (1UL << page_shift),
-					__pa(page_address(pages[i])), prot,
+					page_to_phys(pages[i]), prot,
 					page_shift);
 		if (err)
 			return err;