mm/readahead.c, mm/vmscan.c: use lru_to_page instead of list_to_page

list_to_page() in readahead.c is the same as lru_to_page() in vmscan.c.
So I move lru_to_page to internal.h and drop list_to_page().
Signed-off-by: NGeliang Tang <geliangtang@163.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

mm/internal.h

@@ -119,6 +119,8 @@ extern int isolate_lru_page(struct page *page);
 extern void putback_lru_page(struct page *page);
 extern bool zone_reclaimable(struct zone *zone);
 
+#define lru_to_page(_head) (list_entry((_head)->prev, struct page, lru))
+
 /*
  * in mm/rmap.c:
  */

mm/readahead.c

@@ -32,8 +32,6 @@ file_ra_state_init(struct file_ra_state *ra, struct address_space *mapping)
 }
 EXPORT_SYMBOL_GPL(file_ra_state_init);
 
-#define list_to_page(head) (list_entry((head)->prev, struct page, lru))
-
 /*
  * see if a page needs releasing upon read_cache_pages() failure
  * - the caller of read_cache_pages() may have set PG_private or PG_fscache
@@ -64,7 +62,7 @@ static void read_cache_pages_invalidate_pages(struct address_space *mapping,
 	struct page *victim;
 
 	while (!list_empty(pages)) {
-		victim = list_to_page(pages);
+		victim = lru_to_page(pages);
 		list_del(&victim->lru);
 		read_cache_pages_invalidate_page(mapping, victim);
 	}
@@ -87,7 +85,7 @@ int read_cache_pages(struct address_space *mapping, struct list_head *pages,
 	int ret = 0;
 
 	while (!list_empty(pages)) {
-		page = list_to_page(pages);
+		page = lru_to_page(pages);
 		list_del(&page->lru);
 		if (add_to_page_cache_lru(page, mapping, page->index,
 				mapping_gfp_constraint(mapping, GFP_KERNEL))) {
@@ -125,7 +123,7 @@ static int read_pages(struct address_space *mapping, struct file *filp,
 	}
 
 	for (page_idx = 0; page_idx < nr_pages; page_idx++) {
-		struct page *page = list_to_page(pages);
+		struct page *page = lru_to_page(pages);
 		list_del(&page->lru);
 		if (!add_to_page_cache_lru(page, mapping, page->index,
 				mapping_gfp_constraint(mapping, GFP_KERNEL))) {

mm/vmscan.c

@@ -106,8 +106,6 @@ struct scan_control {
 	unsigned long nr_reclaimed;
 };
 
-#define lru_to_page(_head) (list_entry((_head)->prev, struct page, lru))
-
 #ifdef ARCH_HAS_PREFETCH
 #define prefetch_prev_lru_page(_page, _base, _field)			\
 	do {								\