365 	struct page *page;  in break_ksm()  local
370 		page = follow_page(vma, addr, FOLL_GET | FOLL_MIGRATION);  in break_ksm()
371 		if (IS_ERR_OR_NULL(page))  in break_ksm()
373 		if (PageKsm(page))  in break_ksm()
378 		put_page(page);  in break_ksm()
444 static struct page *page_trans_compound_anon(struct page *page)  in page_trans_compound_anon()  argument
446 	if (PageTransCompound(page)) {  in page_trans_compound_anon()
447 		struct page *head = compound_head(page);  in page_trans_compound_anon()
458 static struct page *get_mergeable_page(struct rmap_item *rmap_item)  in get_mergeable_page()
463 	struct page *page;  in get_mergeable_page()  local
470 	page = follow_page(vma, addr, FOLL_GET);  in get_mergeable_page()
471 	if (IS_ERR_OR_NULL(page))  in get_mergeable_page()
473 	if (PageAnon(page) || page_trans_compound_anon(page)) {  in get_mergeable_page()
474 		flush_anon_page(vma, page, addr);  in get_mergeable_page()
475 		flush_dcache_page(page);  in get_mergeable_page()
477 		put_page(page);  in get_mergeable_page()
478 out:		page = NULL;  in get_mergeable_page()
481 	return page;  in get_mergeable_page()
536 static struct page *get_ksm_page(struct stable_node *stable_node, bool lock_it)  in get_ksm_page()
538 	struct page *page;  in get_ksm_page()  local
546 	page = pfn_to_page(kpfn);  in get_ksm_page()
554 	if (READ_ONCE(page->mapping) != expected_mapping)  in get_ksm_page()
566 	while (!get_page_unless_zero(page)) {  in get_ksm_page()
575 		if (!PageSwapCache(page))  in get_ksm_page()
580 	if (READ_ONCE(page->mapping) != expected_mapping) {  in get_ksm_page()
581 		put_page(page);  in get_ksm_page()
586 		lock_page(page);  in get_ksm_page()
587 		if (READ_ONCE(page->mapping) != expected_mapping) {  in get_ksm_page()
588 			unlock_page(page);  in get_ksm_page()
589 			put_page(page);  in get_ksm_page()
593 	return page;  in get_ksm_page()
617 		struct page *page;  in remove_rmap_item_from_tree()  local
620 		page = get_ksm_page(stable_node, true);  in remove_rmap_item_from_tree()
621 		if (!page)  in remove_rmap_item_from_tree()
625 		unlock_page(page);  in remove_rmap_item_from_tree()
626 		put_page(page);  in remove_rmap_item_from_tree()
704 	struct page *page;  in remove_stable_node()  local
707 	page = get_ksm_page(stable_node, true);  in remove_stable_node()
708 	if (!page) {  in remove_stable_node()
715 	if (WARN_ON_ONCE(page_mapped(page))) {  in remove_stable_node()
730 		set_page_stable_node(page, NULL);  in remove_stable_node()
735 	unlock_page(page);  in remove_stable_node()
736 	put_page(page);  in remove_stable_node()
828 static u32 calc_checksum(struct page *page)  in calc_checksum()  argument
831 	void *addr = kmap_atomic(page);  in calc_checksum()
837 static int memcmp_pages(struct page *page1, struct page *page2)  in memcmp_pages()
850 static inline int pages_identical(struct page *page1, struct page *page2)  in pages_identical()
855 static int write_protect_page(struct vm_area_struct *vma, struct page *page,  in write_protect_page()  argument
867 	addr = page_address_in_vma(page, vma);  in write_protect_page()
871 	BUG_ON(PageTransCompound(page));  in write_protect_page()
877 	ptep = page_check_address(page, mm, addr, &ptl, 0);  in write_protect_page()
884 		swapped = PageSwapCache(page);  in write_protect_page()
885 		flush_cache_page(vma, addr, page_to_pfn(page));  in write_protect_page()
900 		if (page_mapcount(page) + 1 + swapped != page_count(page)) {  in write_protect_page()
905 			set_page_dirty(page);  in write_protect_page()
929 static int replace_page(struct vm_area_struct *vma, struct page *page,  in replace_page()  argument
930 			struct page *kpage, pte_t orig_pte)  in replace_page()
941 	addr = page_address_in_vma(page, vma);  in replace_page()
966 	page_remove_rmap(page);  in replace_page()
967 	if (!page_mapped(page))  in replace_page()
968 		try_to_free_swap(page);  in replace_page()
969 	put_page(page);  in replace_page()
979 static int page_trans_compound_anon_split(struct page *page)  in page_trans_compound_anon_split()  argument
982 	struct page *transhuge_head = page_trans_compound_anon(page);  in page_trans_compound_anon_split()
1016 				 struct page *page, struct page *kpage)  in try_to_merge_one_page()  argument
1021 	if (page == kpage)			/* ksm page forked */  in try_to_merge_one_page()
1026 	if (PageTransCompound(page) && page_trans_compound_anon_split(page))  in try_to_merge_one_page()
1028 	BUG_ON(PageTransCompound(page));  in try_to_merge_one_page()
1029 	if (!PageAnon(page))  in try_to_merge_one_page()
1039 	if (!trylock_page(page))  in try_to_merge_one_page()
1047 	if (write_protect_page(vma, page, &orig_pte) == 0) {  in try_to_merge_one_page()
1054 			set_page_stable_node(page, NULL);  in try_to_merge_one_page()
1055 			mark_page_accessed(page);  in try_to_merge_one_page()
1057 		} else if (pages_identical(page, kpage))  in try_to_merge_one_page()
1058 			err = replace_page(vma, page, kpage, orig_pte);  in try_to_merge_one_page()
1062 		munlock_vma_page(page);  in try_to_merge_one_page()
1064 			unlock_page(page);  in try_to_merge_one_page()
1067 			page = kpage;		/* for final unlock */  in try_to_merge_one_page()
1071 	unlock_page(page);  in try_to_merge_one_page()
1083 				      struct page *page, struct page *kpage)  in try_to_merge_with_ksm_page()  argument
1096 	err = try_to_merge_one_page(vma, page, kpage);  in try_to_merge_with_ksm_page()
1121 static struct page *try_to_merge_two_pages(struct rmap_item *rmap_item,  in try_to_merge_two_pages()
1122 					   struct page *page,  in try_to_merge_two_pages()  argument
1124 					   struct page *tree_page)  in try_to_merge_two_pages()
1128 	err = try_to_merge_with_ksm_page(rmap_item, page, NULL);  in try_to_merge_two_pages()
1131 							tree_page, page);  in try_to_merge_two_pages()
1139 	return err ? NULL : page;  in try_to_merge_two_pages()
1151 static struct page *stable_tree_search(struct page *page)  in stable_tree_search()  argument
1160 	page_node = page_stable_node(page);  in stable_tree_search()
1163 		get_page(page);  in stable_tree_search()
1164 		return page;  in stable_tree_search()
1167 	nid = get_kpfn_nid(page_to_pfn(page));  in stable_tree_search()
1174 		struct page *tree_page;  in stable_tree_search()
1183 		ret = memcmp_pages(page, tree_page);  in stable_tree_search()
1226 	get_page(page);  in stable_tree_search()
1227 	return page;  in stable_tree_search()
1234 		get_page(page);  in stable_tree_search()
1237 		page = NULL;  in stable_tree_search()
1241 	return page;  in stable_tree_search()
1251 static struct stable_node *stable_tree_insert(struct page *kpage)  in stable_tree_insert()
1266 		struct page *tree_page;  in stable_tree_insert()
1323 					      struct page *page,  in unstable_tree_search_insert()  argument
1324 					      struct page **tree_pagep)  in unstable_tree_search_insert()
1331 	nid = get_kpfn_nid(page_to_pfn(page));  in unstable_tree_search_insert()
1337 		struct page *tree_page;  in unstable_tree_search_insert()
1349 		if (page == tree_page) {  in unstable_tree_search_insert()
1354 		ret = memcmp_pages(page, tree_page);  in unstable_tree_search_insert()
1415 static void cmp_and_merge_page(struct page *page, struct rmap_item *rmap_item)  in cmp_and_merge_page()  argument
1418 	struct page *tree_page = NULL;  in cmp_and_merge_page()
1420 	struct page *kpage;  in cmp_and_merge_page()
1424 	stable_node = page_stable_node(page);  in cmp_and_merge_page()
1439 	kpage = stable_tree_search(page);  in cmp_and_merge_page()
1440 	if (kpage == page && rmap_item->head == stable_node) {  in cmp_and_merge_page()
1448 		err = try_to_merge_with_ksm_page(rmap_item, page, kpage);  in cmp_and_merge_page()
1468 	checksum = calc_checksum(page);  in cmp_and_merge_page()
1475 		unstable_tree_search_insert(rmap_item, page, &tree_page);  in cmp_and_merge_page()
1477 		kpage = try_to_merge_two_pages(rmap_item, page,  in cmp_and_merge_page()
1535 static struct rmap_item *scan_get_next_rmap_item(struct page **page)  in scan_get_next_rmap_item()  argument
1569 			struct page *page;  in scan_get_next_rmap_item()  local
1574 				page = get_ksm_page(stable_node, false);  in scan_get_next_rmap_item()
1575 				if (page)  in scan_get_next_rmap_item()
1576 					put_page(page);  in scan_get_next_rmap_item()
1617 			*page = follow_page(vma, ksm_scan.address, FOLL_GET);  in scan_get_next_rmap_item()
1618 			if (IS_ERR_OR_NULL(*page)) {  in scan_get_next_rmap_item()
1623 			if (PageAnon(*page) ||  in scan_get_next_rmap_item()
1624 			    page_trans_compound_anon(*page)) {  in scan_get_next_rmap_item()
1625 				flush_anon_page(vma, *page, ksm_scan.address);  in scan_get_next_rmap_item()
1626 				flush_dcache_page(*page);  in scan_get_next_rmap_item()
1634 					put_page(*page);  in scan_get_next_rmap_item()
1638 			put_page(*page);  in scan_get_next_rmap_item()
1696 	struct page *uninitialized_var(page);  in ksm_do_scan()
1700 		rmap_item = scan_get_next_rmap_item(&page);  in ksm_do_scan()
1703 		cmp_and_merge_page(page, rmap_item);  in ksm_do_scan()
1704 		put_page(page);  in ksm_do_scan()
1862 struct page *ksm_might_need_to_copy(struct page *page,  in ksm_might_need_to_copy()  argument
1865 	struct anon_vma *anon_vma = page_anon_vma(page);  in ksm_might_need_to_copy()
1866 	struct page *new_page;  in ksm_might_need_to_copy()
1868 	if (PageKsm(page)) {  in ksm_might_need_to_copy()
1869 		if (page_stable_node(page) &&  in ksm_might_need_to_copy()
1871 			return page;	/* no need to copy it */  in ksm_might_need_to_copy()
1873 		return page;		/* no need to copy it */  in ksm_might_need_to_copy()
1875 		 page->index == linear_page_index(vma, address)) {  in ksm_might_need_to_copy()
1876 		return page;		/* still no need to copy it */  in ksm_might_need_to_copy()
1878 	if (!PageUptodate(page))  in ksm_might_need_to_copy()
1879 		return page;		/* let do_swap_page report the error */  in ksm_might_need_to_copy()
1883 		copy_user_highpage(new_page, page, address, vma);  in ksm_might_need_to_copy()
1893 int rmap_walk_ksm(struct page *page, struct rmap_walk_control *rwc)  in rmap_walk_ksm()  argument
1900 	VM_BUG_ON_PAGE(!PageKsm(page), page);  in rmap_walk_ksm()
1906 	VM_BUG_ON_PAGE(!PageLocked(page), page);  in rmap_walk_ksm()
1908 	stable_node = page_stable_node(page);  in rmap_walk_ksm()
1936 			ret = rwc->rmap_one(page, vma,  in rmap_walk_ksm()
1942 			if (rwc->done && rwc->done(page)) {  in rmap_walk_ksm()
1956 void ksm_migrate_page(struct page *newpage, struct page *oldpage)  in ksm_migrate_page()