mm-fix-declarations-of-nr-delta-and-nr_pagecache_reclaimable-fix

mm-fix-declarations-of-nr-delta-and-nr_pagecache_reclaimable-fix

Make zone_pagecache_reclaimable() return ulong rather than long.  Negative
values are meainingless here and all zone_pagecache_reclaimable() callers
turn its retrun value into ulong anyway.

Cc: Vladimir Davydov <vdavydov@parallels.com>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Alexandru Moise <00moses.alexander00@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>