memcg: use proper type for mod_memcg_state

The memcg stats update functions can take arbitrary integer but the only
input which make sense is enum memcg_stat_item and we don't want these
functions to be called with arbitrary integer, so replace the parameter
type with enum memcg_stat_item and compiler will be able to warn if memcg
stat update functions are called with incorrect index value.

Link: https://lkml.kernel.org/r/20240501172617.678560-9-shakeel.butt@linux.dev
Signed-off-by: Shakeel Butt <shakeel.butt@linux.dev>
Reviewed-by: T.J. Mercier <tjmercier@google.com>
Reviewed-by: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Yosry Ahmed <yosryahmed@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
index ab8a6e884375d366e766965b43801f8c7b1a9d0a..030d34e9d1176fba263ad2bb07c6da28a6848f14 100644 (file)
--- a/include/linux/memcontrol.h
+++ b/include/linux/memcontrol.h
@@ -974,7 +974,8 @@ void mem_cgroup_print_oom_group(struct mem_cgroup *memcg);
 void folio_memcg_lock(struct folio *folio);
 void folio_memcg_unlock(struct folio *folio);
 
-void __mod_memcg_state(struct mem_cgroup *memcg, int idx, int val);
+void __mod_memcg_state(struct mem_cgroup *memcg, enum memcg_stat_item idx,
+                      int val);
 
 /* try to stablize folio_memcg() for all the pages in a memcg */
 static inline bool mem_cgroup_trylock_pages(struct mem_cgroup *memcg)
@@ -995,7 +996,7 @@ static inline void mem_cgroup_unlock_pages(void)
 
 /* idx can be of type enum memcg_stat_item or node_stat_item */
 static inline void mod_memcg_state(struct mem_cgroup *memcg,
-                                  int idx, int val)
+                                  enum memcg_stat_item idx, int val)
 {
        unsigned long flags;
 
@@ -1005,7 +1006,7 @@ static inline void mod_memcg_state(struct mem_cgroup *memcg,
 }
 
 static inline void mod_memcg_page_state(struct page *page,
-                                       int idx, int val)
+                                       enum memcg_stat_item idx, int val)
 {
        struct mem_cgroup *memcg;
 
@@ -1491,19 +1492,19 @@ static inline void mem_cgroup_print_oom_group(struct mem_cgroup *memcg)
 }
 
 static inline void __mod_memcg_state(struct mem_cgroup *memcg,
-                                    int idx,
+                                    enum memcg_stat_item idx,
                                     int nr)
 {
 }
 
 static inline void mod_memcg_state(struct mem_cgroup *memcg,
-                                  int idx,
+                                  enum memcg_stat_item idx,
                                   int nr)
 {
 }
 
 static inline void mod_memcg_page_state(struct page *page,
-                                       int idx, int val)
+                                       enum memcg_stat_item idx, int val)
 {
 }
 

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 87411116ec5e62c496d3fcd946d0b70c2c77c4f2..e6302f42e40f13177817e00ca6d06cead4da2f50 100644 (file)
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -955,7 +955,8 @@ static int memcg_state_val_in_pages(int idx, int val)
  * @idx: the stat item - can be enum memcg_stat_item or enum node_stat_item
  * @val: delta to add to the counter, can be negative
  */
-void __mod_memcg_state(struct mem_cgroup *memcg, int idx, int val)
+void __mod_memcg_state(struct mem_cgroup *memcg, enum memcg_stat_item idx,
+                      int val)
 {
        int i = memcg_stats_index(idx);