mm/compaction: call list_is_{first}/{last} more intuitively in move_freelist_{head}/{tail}

We use move_freelist_head after list_for_each_entry_reverse to skip recent
pages.  And there is no need to do actual move if all freepages are
searched in list_for_each_entry_reverse, e.g.  freepage point to first
page in freelist.  It's more intuitively to call list_is_first with list
entry as the first argument and list head as the second argument to check
if list entry is the first list entry instead of call list_is_last with
list entry and list head passed in reverse.

Similarly, call list_is_last in move_freelist_tail is more intuitively.

Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Kemeng Shi <[email protected]>
Reviewed-by: Baolin Wang <[email protected]>
Acked-by: Mel Gorman <[email protected]>
Cc: David Hildenbrand <[email protected]>
Cc: Matthew Wilcox (Oracle) <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

Author: Kemeng Shi

mm/compaction.c

@@ -1395,7 +1395,7 @@ move_freelist_head(struct list_head *freelist, struct page *freepage)
 {
 	LIST_HEAD(sublist);
 
-	if (!list_is_last(freelist, &freepage->buddy_list)) {
+	if (!list_is_first(&freepage->buddy_list, freelist)) {
 		list_cut_before(&sublist, freelist, &freepage->buddy_list);
 		list_splice_tail(&sublist, freelist);
 	}
@@ -1412,7 +1412,7 @@ move_freelist_tail(struct list_head *freelist, struct page *freepage)
 {
 	LIST_HEAD(sublist);
 
-	if (!list_is_first(freelist, &freepage->buddy_list)) {
+	if (!list_is_last(&freepage->buddy_list, freelist)) {
 		list_cut_position(&sublist, freelist, &freepage->buddy_list);
 		list_splice_tail(&sublist, freelist);
 	}