mm: memcontrol: constify the reclaim protection helpers

mem_cgroup_protection(), mem_cgroup_unprotected(), mem_cgroup_below_low(),
and mem_cgroup_below_min() only read the protection state.  Constify them.

Link: https://lore.kernel.org/20260915-folio_memcg-const-v3-7-c239a6010b58@columbia.edu
Signed-off-by: Tal Zussman <tz2294@columbia.edu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Muchun Song <muchun.song@linux.dev>
Acked-by: Shakeel Butt <shakeel.butt@linux.dev>
Acked-by: Lorenzo Stoakes (ARM) <ljs@kernel.org>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Baoquan He <baoquan.he@linux.dev>
Cc: Barry Song <baohua@kernel.org>
Cc: Chris Li <chrisl@kernel.org>
Cc: David Hildenbrand <david@kernel.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Kairui Song <kasong@tencent.com>
Cc: Kemeng Shi <shikemeng@huaweicloud.com>
Cc: Liam R. Howlett <liam@infradead.org>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Nhat Pham <nphamcs@gmail.com>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Cc: Wei Xu <weixugc@google.com>
Cc: Yuanchu Xie <yuanchu@google.com>

1 files changed, 16 insertions, 16 deletions

diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
index 01f74413fc79..22067899eb6c 100644
--- a/include/linux/memcontrol.h
+++ b/include/linux/memcontrol.h
@@ -570,8 +570,8 @@ static inline bool mem_cgroup_disabled(void)
 	return !cgroup_subsys_enabled(memory_cgrp_subsys);
 }
 
-static inline void mem_cgroup_protection(struct mem_cgroup *root,
-					 struct mem_cgroup *memcg,
+static inline void mem_cgroup_protection(const struct mem_cgroup *root,
+					 const struct mem_cgroup *memcg,
 					 unsigned long *min,
 					 unsigned long *low,
 					 unsigned long *usage)
@@ -625,8 +625,8 @@ static inline void mem_cgroup_protection(struct mem_cgroup *root,
 void mem_cgroup_calculate_protection(struct mem_cgroup *root,
 				     struct mem_cgroup *memcg);
 
-static inline bool mem_cgroup_unprotected(struct mem_cgroup *target,
-					  struct mem_cgroup *memcg)
+static inline bool mem_cgroup_unprotected(const struct mem_cgroup *target,
+					  const struct mem_cgroup *memcg)
 {
 	/*
 	 * The root memcg doesn't account charges, and doesn't support
@@ -637,8 +637,8 @@ static inline bool mem_cgroup_unprotected(struct mem_cgroup *target,
 		memcg == target;
 }
 
-static inline bool mem_cgroup_below_low(struct mem_cgroup *target,
-					struct mem_cgroup *memcg)
+static inline bool mem_cgroup_below_low(const struct mem_cgroup *target,
+					const struct mem_cgroup *memcg)
 {
 	if (mem_cgroup_unprotected(target, memcg))
 		return false;
@@ -647,8 +647,8 @@ static inline bool mem_cgroup_below_low(struct mem_cgroup *target,
 		page_counter_read(&memcg->memory);
 }
 
-static inline bool mem_cgroup_below_min(struct mem_cgroup *target,
-					struct mem_cgroup *memcg)
+static inline bool mem_cgroup_below_min(const struct mem_cgroup *target,
+					const struct mem_cgroup *memcg)
 {
 	if (mem_cgroup_unprotected(target, memcg))
 		return false;
@@ -1149,8 +1149,8 @@ static inline void memcg_memory_event_mm(struct mm_struct *mm,
 {
 }
 
-static inline void mem_cgroup_protection(struct mem_cgroup *root,
-					 struct mem_cgroup *memcg,
+static inline void mem_cgroup_protection(const struct mem_cgroup *root,
+					 const struct mem_cgroup *memcg,
 					 unsigned long *min,
 					 unsigned long *low,
 					 unsigned long *usage)
@@ -1163,19 +1163,19 @@ static inline void mem_cgroup_calculate_protection(struct mem_cgroup *root,
 {
 }
 
-static inline bool mem_cgroup_unprotected(struct mem_cgroup *target,
-					  struct mem_cgroup *memcg)
+static inline bool mem_cgroup_unprotected(const struct mem_cgroup *target,
+					  const struct mem_cgroup *memcg)
 {
 	return true;
 }
-static inline bool mem_cgroup_below_low(struct mem_cgroup *target,
-					struct mem_cgroup *memcg)
+static inline bool mem_cgroup_below_low(const struct mem_cgroup *target,
+					const struct mem_cgroup *memcg)
 {
 	return false;
 }
 
-static inline bool mem_cgroup_below_min(struct mem_cgroup *target,
-					struct mem_cgroup *memcg)
+static inline bool mem_cgroup_below_min(const struct mem_cgroup *target,
+					const struct mem_cgroup *memcg)
 {
 	return false;
 }