mm: reuse pageblock_start/end_pfn() macro

Move pageblock_start_pfn/pageblock_end_pfn() into pageblock-flags.h, then
they could be used somewhere else, not only in compaction, also use
ALIGN_DOWN() instead of round_down() to be pair with ALIGN(), which should
be same for pageblock usage.

Link: https://lkml.kernel.org/r/[e-mail]
Signed-off-by: Kefeng Wang <[e-mail]>
Acked-by: Mike Rapoport <[e-mail]>
Reviewed-by: David Hildenbrand <[e-mail]>
Cc: Oscar Salvador <[e-mail]>
Cc: Vlastimil Babka <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>

include/linux/pageblock-flags.h

···
 #endif /* CONFIG_HUGETLB_PAGE */
 
 #define pageblock_nr_pages	(1UL << pageblock_order)
+#define pageblock_start_pfn(pfn)	ALIGN_DOWN((pfn), pageblock_nr_pages)
+#define pageblock_end_pfn(pfn)		ALIGN((pfn) + 1, pageblock_nr_pages)
 
 /* Forward declaration */
 struct page;

mm/compaction.c

···
 
 #define block_start_pfn(pfn, order)	round_down(pfn, 1UL << (order))
 #define block_end_pfn(pfn, order)	ALIGN((pfn) + 1, 1UL << (order))
-#define pageblock_start_pfn(pfn)	block_start_pfn(pfn, pageblock_order)
-#define pageblock_end_pfn(pfn)		block_end_pfn(pfn, pageblock_order)
 
 /*
  * Page order with-respect-to which proactive compaction

mm/memblock.c

···
 		 * presume that there are no holes in the memory map inside
 		 * a pageblock
 		 */
-		start = round_down(start, pageblock_nr_pages);
+		start = pageblock_start_pfn(start);
 
 		/*
 		 * If we had a previous bank, and there is a space

mm/page_alloc.c

···
 #ifdef CONFIG_SPARSEMEM
 	pfn &= (PAGES_PER_SECTION-1);
 #else
-	pfn = pfn - round_down(page_zone(page)->zone_start_pfn, pageblock_nr_pages);
+	pfn = pfn - pageblock_start_pfn(page_zone(page)->zone_start_pfn);
 #endif /* CONFIG_SPARSEMEM */
 	return (pfn >> pageblock_order) * NR_PAGEBLOCK_BITS;
 }
···
 	unsigned long block_start_pfn = zone->zone_start_pfn;
 	unsigned long block_end_pfn;
 
-	block_end_pfn = ALIGN(block_start_pfn + 1, pageblock_nr_pages);
+	block_end_pfn = pageblock_end_pfn(block_start_pfn);
 	for (; block_start_pfn < zone_end_pfn(zone);
 			block_start_pfn = block_end_pfn,
 			 block_end_pfn += pageblock_nr_pages) {
···
 		*num_movable = 0;
 
 	pfn = page_to_pfn(page);
-	start_pfn = pfn & ~(pageblock_nr_pages - 1);
-	end_pfn = start_pfn + pageblock_nr_pages - 1;
+	start_pfn = pageblock_start_pfn(pfn);
+	end_pfn = pageblock_end_pfn(pfn) - 1;
 
 	/* Do not cross zone boundaries */
 	if (!zone_spans_pfn(zone, start_pfn))
···
 	u64 pgcnt = 0;
 
 	for (pfn = spfn; pfn < epfn; pfn++) {
-		if (!pfn_valid(ALIGN_DOWN(pfn, pageblock_nr_pages))) {
-			pfn = ALIGN_DOWN(pfn, pageblock_nr_pages)
-				+ pageblock_nr_pages - 1;
+		if (!pfn_valid(pageblock_start_pfn(pfn))) {
+			pfn = pageblock_end_pfn(pfn) - 1;
 			continue;
 		}
 		__init_single_page(pfn_to_page(pfn), pfn, zone, node);

mm/page_isolation.c

···
 	struct zone *zone = page_zone(page);
 	unsigned long pfn;
 
-	VM_BUG_ON(ALIGN_DOWN(start_pfn, pageblock_nr_pages) !=
-		  ALIGN_DOWN(end_pfn - 1, pageblock_nr_pages));
+	VM_BUG_ON(pageblock_start_pfn(start_pfn) !=
+		  pageblock_start_pfn(end_pfn - 1));
 
 	if (is_migrate_cma_page(page)) {
 		/*
···
 	 * to avoid redundant checks.
 	 */
 	check_unmovable_start = max(page_to_pfn(page), start_pfn);
-	check_unmovable_end = min(ALIGN(page_to_pfn(page) + 1, pageblock_nr_pages),
+	check_unmovable_end = min(pageblock_end_pfn(page_to_pfn(page)),
 				  end_pfn);
 
 	unmovable = has_unmovable_pages(check_unmovable_start, check_unmovable_end,
···
 	unsigned long pfn;
 	struct page *page;
 	/* isolation is done at page block granularity */
-	unsigned long isolate_start = ALIGN_DOWN(start_pfn, pageblock_nr_pages);
+	unsigned long isolate_start = pageblock_start_pfn(start_pfn);
 	unsigned long isolate_end = ALIGN(end_pfn, pageblock_nr_pages);
 	int ret;
 	bool skip_isolation = false;
···
 {
 	unsigned long pfn;
 	struct page *page;
-	unsigned long isolate_start = ALIGN_DOWN(start_pfn, pageblock_nr_pages);
+	unsigned long isolate_start = pageblock_start_pfn(start_pfn);
 	unsigned long isolate_end = ALIGN(end_pfn, pageblock_nr_pages);
-
 
 	for (pfn = isolate_start;
 	     pfn < isolate_end;

mm/page_owner.c

···
 			continue;
 		}
 
-		block_end_pfn = ALIGN(pfn + 1, pageblock_nr_pages);
+		block_end_pfn = pageblock_end_pfn(pfn);
 		block_end_pfn = min(block_end_pfn, end_pfn);
 
 		pageblock_mt = get_pageblock_migratetype(page);
···
 			continue;
 		}
 
-		block_end_pfn = ALIGN(pfn + 1, pageblock_nr_pages);
+		block_end_pfn = pageblock_end_pfn(pfn);
 		block_end_pfn = min(block_end_pfn, end_pfn);
 
 		for (; pfn < block_end_pfn; pfn++) {