mm/vmscan.c: fix types of some locals

In zone_reclaimable_pages(), `nr' is returned by a function which is
declared as returning "unsigned long", so declare it such.  Negative
values are meaningless here.

In zone_pagecache_reclaimable() we should also declare `delta' and
`nr_pagecache_reclaimable' as being unsigned longs because they're used to
store the values returned by zone_page_state() and
zone_unmapped_file_pages() which also happen to return unsigned integers.

[akpm@linux-foundation.org: make zone_pagecache_reclaimable() return ulong rather than long]
Signed-off-by: Alexandru Moise <00moses.alexander00@gmail.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Vladimir Davydov <vdavydov@parallels.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Mel Gorman <mgorman@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm/vmscan.c

@@ -194,7 +194,7 @@ static bool sane_reclaim(struct scan_control *sc)
 
 static unsigned long zone_reclaimable_pages(struct zone *zone)
 {
-	int nr;
+	unsigned long nr;
 
 	nr = zone_page_state(zone, NR_ACTIVE_FILE) +
 	     zone_page_state(zone, NR_INACTIVE_FILE);
@@ -3693,10 +3693,10 @@ static inline unsigned long zone_unmapped_file_pages(struct zone *zone)
 }
 
 /* Work out how many page cache pages we can reclaim in this reclaim_mode */
-static long zone_pagecache_reclaimable(struct zone *zone)
+static unsigned long zone_pagecache_reclaimable(struct zone *zone)
 {
-	long nr_pagecache_reclaimable;
-	long delta = 0;
+	unsigned long nr_pagecache_reclaimable;
+	unsigned long delta = 0;
 
 	/*
 	 * If RECLAIM_UNMAP is set, then all file pages are considered