[PATCH 1/7] mm: fix return type for functions nr_free_*_pages

[Zhang Yanfei <zhangyanfei@xxxxxxxxxxxxxx>]

Currently, the amount of RAM that functions nr_free_*_pages return
is held in unsigned int. But in machines with big memory (exceeding
16TB), the amount may be incorrect because of overflow, so fix it.

Signed-off-by: Zhang Yanfei <zhangyanfei@xxxxxxxxxxxxxx>
---
 include/linux/swap.h |    4 ++--
 mm/page_alloc.c      |    8 ++++----
 2 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/include/linux/swap.h b/include/linux/swap.h
index 68df9c1..c238323 100644
--- a/include/linux/swap.h
+++ b/include/linux/swap.h
@@ -216,8 +216,8 @@ struct swap_list_t {
 extern unsigned long totalram_pages;
 extern unsigned long totalreserve_pages;
 extern unsigned long dirty_balance_reserve;
-extern unsigned int nr_free_buffer_pages(void);
-extern unsigned int nr_free_pagecache_pages(void);
+extern unsigned long nr_free_buffer_pages(void);
+extern unsigned long nr_free_pagecache_pages(void);
 
 /* Definition of global_page_state not available yet */
 #define nr_free_pages() global_page_state(NR_FREE_PAGES)
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index df2022f..4acf733 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -2785,13 +2785,13 @@ void free_pages_exact(void *virt, size_t size)
 }
 EXPORT_SYMBOL(free_pages_exact);
 
-static unsigned int nr_free_zone_pages(int offset)
+static unsigned long nr_free_zone_pages(int offset)
 {
 	struct zoneref *z;
 	struct zone *zone;
 
 	/* Just pick one node, since fallback list is circular */
-	unsigned int sum = 0;
+	unsigned long sum = 0;
 
 	struct zonelist *zonelist = node_zonelist(numa_node_id(), GFP_KERNEL);
 
@@ -2808,7 +2808,7 @@ static unsigned int nr_free_zone_pages(int offset)
 /*
  * Amount of free RAM allocatable within ZONE_DMA and ZONE_NORMAL
  */
-unsigned int nr_free_buffer_pages(void)
+unsigned long nr_free_buffer_pages(void)
 {
 	return nr_free_zone_pages(gfp_zone(GFP_USER));
 }
@@ -2817,7 +2817,7 @@ EXPORT_SYMBOL_GPL(nr_free_buffer_pages);
 /*
  * Amount of free RAM allocatable within all zones
  */
-unsigned int nr_free_pagecache_pages(void)
+unsigned long nr_free_pagecache_pages(void)
 {
 	return nr_free_zone_pages(gfp_zone(GFP_HIGHUSER_MOVABLE));
 }
-- 
1.7.1

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