[PATCH] mm/bpf_memcontrol: mark BPF memcg kfuncs static

[JP Kobryn]

The kfuncs in bpf_memcontrol.c are not called by in-kernel C code. They are
only referenced by BPF programs and resolved through BTF.

Since no external linkage is needed, mark these functions static.

Fixes: 5904db9891f8 ("mm: introduce BPF kfuncs to deal with memcg pointers")
Fixes: 5c7db3239c9f ("mm: introduce bpf_get_root_mem_cgroup() BPF kfunc")
Fixes: 99430ab8b804 ("mm: introduce BPF kfuncs to access memcg statistics and events")
Reported-by: kernel test robot <lkp@xxxxxxxxx>
Closes: https://lore.kernel.org/oe-kbuild-all/202606150332.Xy4Egd9s-lkp@xxxxxxxxx/
Signed-off-by: JP Kobryn <jp.kobryn@xxxxxxxxx>
---
 mm/bpf_memcontrol.c | 21 +++++++++++----------
 1 file changed, 11 insertions(+), 10 deletions(-)

diff --git a/mm/bpf_memcontrol.c b/mm/bpf_memcontrol.c
index 716df49d7647..eff79bb2c758 100644
--- a/mm/bpf_memcontrol.c
+++ b/mm/bpf_memcontrol.c
@@ -20,7 +20,7 @@ __bpf_kfunc_start_defs();
  *
  * Return: A pointer to the root memory cgroup.
  */
-__bpf_kfunc struct mem_cgroup *bpf_get_root_mem_cgroup(void)
+__bpf_kfunc static struct mem_cgroup *bpf_get_root_mem_cgroup(void)
 {
 	if (mem_cgroup_disabled())
 		return NULL;
@@ -41,7 +41,7 @@ __bpf_kfunc struct mem_cgroup *bpf_get_root_mem_cgroup(void)
  * Return: A pointer to a mem_cgroup structure after bumping
  * the corresponding css's reference counter.
  */
-__bpf_kfunc struct mem_cgroup *
+__bpf_kfunc static struct mem_cgroup *
 bpf_get_mem_cgroup(struct cgroup_subsys_state *css)
 {
 	struct mem_cgroup *memcg = NULL;
@@ -75,7 +75,7 @@ bpf_get_mem_cgroup(struct cgroup_subsys_state *css)
  * Releases a previously acquired memcg reference.
  * Implements KF_RELEASE semantics.
  */
-__bpf_kfunc void bpf_put_mem_cgroup(struct mem_cgroup *memcg)
+__bpf_kfunc static void bpf_put_mem_cgroup(struct mem_cgroup *memcg)
 {
 	css_put(&memcg->css);
 }
@@ -89,8 +89,8 @@ __bpf_kfunc void bpf_put_mem_cgroup(struct mem_cgroup *memcg)
  *
  * Return: The current value of the corresponding events counter.
  */
-__bpf_kfunc unsigned long bpf_mem_cgroup_vm_events(struct mem_cgroup *memcg,
-						   enum vm_event_item event)
+__bpf_kfunc static unsigned long
+bpf_mem_cgroup_vm_events(struct mem_cgroup *memcg, enum vm_event_item event)
 {
 	if (unlikely(!memcg_vm_event_item_valid(event)))
 		return (unsigned long)-1;
@@ -110,7 +110,7 @@ __bpf_kfunc unsigned long bpf_mem_cgroup_vm_events(struct mem_cgroup *memcg,
  *
  * Return: The current memory cgroup size in bytes.
  */
-__bpf_kfunc unsigned long bpf_mem_cgroup_usage(struct mem_cgroup *memcg)
+__bpf_kfunc static unsigned long bpf_mem_cgroup_usage(struct mem_cgroup *memcg)
 {
 	return page_counter_read(&memcg->memory) * PAGE_SIZE;
 }
@@ -122,8 +122,8 @@ __bpf_kfunc unsigned long bpf_mem_cgroup_usage(struct mem_cgroup *memcg)
  *
  * Return: The current value of the memory event counter.
  */
-__bpf_kfunc unsigned long bpf_mem_cgroup_memory_events(struct mem_cgroup *memcg,
-						       enum memcg_memory_event event)
+__bpf_kfunc static unsigned long
+bpf_mem_cgroup_memory_events(struct mem_cgroup *memcg, enum memcg_memory_event event)
 {
 	if (unlikely(event >= MEMCG_NR_MEMORY_EVENTS))
 		return (unsigned long)-1;
@@ -140,7 +140,8 @@ __bpf_kfunc unsigned long bpf_mem_cgroup_memory_events(struct mem_cgroup *memcg,
  *
  * Return: The value of the page state counter in bytes.
  */
-__bpf_kfunc unsigned long bpf_mem_cgroup_page_state(struct mem_cgroup *memcg, int idx)
+__bpf_kfunc static unsigned long
+bpf_mem_cgroup_page_state(struct mem_cgroup *memcg, int idx)
 {
 	if (unlikely(!memcg_stat_item_valid(idx)))
 		return (unsigned long)-1;
@@ -154,7 +155,7 @@ __bpf_kfunc unsigned long bpf_mem_cgroup_page_state(struct mem_cgroup *memcg, in
  *
  * Propagate memory cgroup's statistics up the cgroup tree.
  */
-__bpf_kfunc void bpf_mem_cgroup_flush_stats(struct mem_cgroup *memcg)
+__bpf_kfunc static void bpf_mem_cgroup_flush_stats(struct mem_cgroup *memcg)
 {
 	mem_cgroup_flush_stats(memcg);
 }
-- 
2.54.0