mm: memcontrol: use int for event/state parameter in several functions

Several functions use an enum type as parameter for an event/state, but
are called in some locations with an argument of a different enum type.
Adjust the interface of these functions to reality by changing the
parameter to int.

This fixes a ton of enum-conversion warnings that are generated when
building the kernel with clang.

[[e-mail]: also change parameter type of inc/dec/mod_memcg_page_state()]
Link: http://lkml.kernel.org/r/[e-mail]
Link: http://lkml.kernel.org/r/[e-mail]
Signed-off-by: Matthias Kaehlcke <[e-mail]>
Acked-by: Johannes Weiner <[e-mail]>
Acked-by: Michal Hocko <[e-mail]>
Cc: Vladimir Davydov <[e-mail]>
Cc: Doug Anderson <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>
Signed-off-by: Linus Torvalds <[e-mail]>

include/linux/memcontrol.h

···
 void __unlock_page_memcg(struct mem_cgroup *memcg);
 void unlock_page_memcg(struct page *page);
 
+/* idx can be of type enum memcg_stat_item or node_stat_item */
 static inline unsigned long memcg_page_state(struct mem_cgroup *memcg,
-					     enum memcg_stat_item idx)
+					     int idx)
 {
 	long val = 0;
 	int cpu;
···
 	return val;
 }
 
+/* idx can be of type enum memcg_stat_item or node_stat_item */
 static inline void __mod_memcg_state(struct mem_cgroup *memcg,
-				     enum memcg_stat_item idx, int val)
+				     int idx, int val)
 {
 	if (!mem_cgroup_disabled())
 		__this_cpu_add(memcg->stat->count[idx], val);
 }
 
+/* idx can be of type enum memcg_stat_item or node_stat_item */
 static inline void mod_memcg_state(struct mem_cgroup *memcg,
-				   enum memcg_stat_item idx, int val)
+				   int idx, int val)
 {
 	if (!mem_cgroup_disabled())
 		this_cpu_add(memcg->stat->count[idx], val);
···
  * Kernel pages are an exception to this, since they'll never move.
  */
 static inline void __mod_memcg_page_state(struct page *page,
-					  enum memcg_stat_item idx, int val)
+					  int idx, int val)
 {
 	if (page->mem_cgroup)
 		__mod_memcg_state(page->mem_cgroup, idx, val);
 }
 
 static inline void mod_memcg_page_state(struct page *page,
-					enum memcg_stat_item idx, int val)
+					int idx, int val)
 {
 	if (page->mem_cgroup)
 		mod_memcg_state(page->mem_cgroup, idx, val);
···
 		this_cpu_add(memcg->stat->events[idx], count);
 }
 
+/* idx can be of type enum memcg_stat_item or node_stat_item */
 static inline void count_memcg_page_event(struct page *page,
-					  enum memcg_stat_item idx)
+					  int idx)
 {
 	if (page->mem_cgroup)
 		count_memcg_events(page->mem_cgroup, idx, 1);
···
 }
 
 static inline unsigned long memcg_page_state(struct mem_cgroup *memcg,
-					     enum memcg_stat_item idx)
+					     int idx)
 {
 	return 0;
 }
 
 static inline void __mod_memcg_state(struct mem_cgroup *memcg,
-				     enum memcg_stat_item idx,
+				     int idx,
 				     int nr)
 {
 }
 
 static inline void mod_memcg_state(struct mem_cgroup *memcg,
-				   enum memcg_stat_item idx,
+				   int idx,
 				   int nr)
 {
 }
 
 static inline void __mod_memcg_page_state(struct page *page,
-					  enum memcg_stat_item idx,
+					  int idx,
 					  int nr)
 {
 }
 
 static inline void mod_memcg_page_state(struct page *page,
-					enum memcg_stat_item idx,
+					int idx,
 					int nr)
 {
 }
···
 }
 
 static inline void count_memcg_page_event(struct page *page,
-					  enum memcg_stat_item idx)
+					  int idx)
 {
 }
 
···
 }
 #endif /* CONFIG_MEMCG */
 
+/* idx can be of type enum memcg_stat_item or node_stat_item */
 static inline void __inc_memcg_state(struct mem_cgroup *memcg,
-				     enum memcg_stat_item idx)
+				     int idx)
 {
 	__mod_memcg_state(memcg, idx, 1);
 }
 
+/* idx can be of type enum memcg_stat_item or node_stat_item */
 static inline void __dec_memcg_state(struct mem_cgroup *memcg,
-				     enum memcg_stat_item idx)
+				     int idx)
 {
 	__mod_memcg_state(memcg, idx, -1);
 }
 
+/* idx can be of type enum memcg_stat_item or node_stat_item */
 static inline void __inc_memcg_page_state(struct page *page,
-					  enum memcg_stat_item idx)
+					  int idx)
 {
 	__mod_memcg_page_state(page, idx, 1);
 }
 
+/* idx can be of type enum memcg_stat_item or node_stat_item */
 static inline void __dec_memcg_page_state(struct page *page,
-					  enum memcg_stat_item idx)
+					  int idx)
 {
 	__mod_memcg_page_state(page, idx, -1);
 }
···
 	__mod_lruvec_page_state(page, idx, -1);
 }
 
+/* idx can be of type enum memcg_stat_item or node_stat_item */
 static inline void inc_memcg_state(struct mem_cgroup *memcg,
-				   enum memcg_stat_item idx)
+				   int idx)
 {
 	mod_memcg_state(memcg, idx, 1);
 }
 
+/* idx can be of type enum memcg_stat_item or node_stat_item */
 static inline void dec_memcg_state(struct mem_cgroup *memcg,
-				   enum memcg_stat_item idx)
+				   int idx)
 {
 	mod_memcg_state(memcg, idx, -1);
 }
 
+/* idx can be of type enum memcg_stat_item or node_stat_item */
 static inline void inc_memcg_page_state(struct page *page,
-					enum memcg_stat_item idx)
+					int idx)
 {
 	mod_memcg_page_state(page, idx, 1);
 }
 
+/* idx can be of type enum memcg_stat_item or node_stat_item */
 static inline void dec_memcg_page_state(struct page *page,
-					enum memcg_stat_item idx)
+					int idx)
 {
 	mod_memcg_page_state(page, idx, -1);
 }

mm/memcontrol.c

···
  * value, and reading all cpu value can be performance bottleneck in some
  * common workload, threshold and synchronization as vmstat[] should be
  * implemented.
+ *
+ * The parameter idx can be of type enum memcg_event_item or vm_event_item.
  */
 
 static unsigned long memcg_sum_events(struct mem_cgroup *memcg,
-				      enum memcg_event_item event)
+				      int event)
 {
 	unsigned long val = 0;
 	int cpu;