mm: clean up zone flags

Page reclaim tests zone_is_reclaim_dirty(), but the site that actually
sets this state does zone_set_flag(zone, ZONE_TAIL_LRU_DIRTY), sending the
reader through layers indirection just to track down a simple bit.

Remove all zone flag wrappers and just use bitops against zone->flags
directly.  It's just as readable and the lines are barely any longer.

Also rename ZONE_TAIL_LRU_DIRTY to ZONE_DIRTY to match ZONE_WRITEBACK, and
remove the zone_flags_t typedef.

Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: David Rientjes <rientjes@google.com>
Acked-by: Mel Gorman <mgorman@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
index 318df70..48bf12e 100644
--- a/include/linux/mmzone.h
+++ b/include/linux/mmzone.h
@@ -521,13 +521,13 @@
 	atomic_long_t		vm_stat[NR_VM_ZONE_STAT_ITEMS];
 } ____cacheline_internodealigned_in_smp;
 
-typedef enum {
+enum zone_flags {
 	ZONE_RECLAIM_LOCKED,		/* prevents concurrent reclaim */
 	ZONE_OOM_LOCKED,		/* zone is in OOM killer zonelist */
 	ZONE_CONGESTED,			/* zone has many dirty pages backed by
 					 * a congested BDI
 					 */
-	ZONE_TAIL_LRU_DIRTY,		/* reclaim scanning has recently found
+	ZONE_DIRTY,			/* reclaim scanning has recently found
 					 * many dirty file pages at the tail
 					 * of the LRU.
 					 */
@@ -535,52 +535,7 @@
 					 * many pages under writeback
 					 */
 	ZONE_FAIR_DEPLETED,		/* fair zone policy batch depleted */
-} zone_flags_t;
-
-static inline void zone_set_flag(struct zone *zone, zone_flags_t flag)
-{
-	set_bit(flag, &zone->flags);
-}
-
-static inline int zone_test_and_set_flag(struct zone *zone, zone_flags_t flag)
-{
-	return test_and_set_bit(flag, &zone->flags);
-}
-
-static inline void zone_clear_flag(struct zone *zone, zone_flags_t flag)
-{
-	clear_bit(flag, &zone->flags);
-}
-
-static inline int zone_is_reclaim_congested(const struct zone *zone)
-{
-	return test_bit(ZONE_CONGESTED, &zone->flags);
-}
-
-static inline int zone_is_reclaim_dirty(const struct zone *zone)
-{
-	return test_bit(ZONE_TAIL_LRU_DIRTY, &zone->flags);
-}
-
-static inline int zone_is_reclaim_writeback(const struct zone *zone)
-{
-	return test_bit(ZONE_WRITEBACK, &zone->flags);
-}
-
-static inline int zone_is_reclaim_locked(const struct zone *zone)
-{
-	return test_bit(ZONE_RECLAIM_LOCKED, &zone->flags);
-}
-
-static inline int zone_is_fair_depleted(const struct zone *zone)
-{
-	return test_bit(ZONE_FAIR_DEPLETED, &zone->flags);
-}
-
-static inline int zone_is_oom_locked(const struct zone *zone)
-{
-	return test_bit(ZONE_OOM_LOCKED, &zone->flags);
-}
+};
 
 static inline unsigned long zone_end_pfn(const struct zone *zone)
 {