[PATCH v5 4/9] mm/page_owner: hoist CONFIG_MEMCG to function level for print_page_owner_memcg()

[Ye Liu <ye.liu@linux.dev>]

The print_page_owner_memcg() function has CONFIG_MEMCG guarding its
entire body via #ifdef inside the function, which leaves a no-op
{ return ret; } when the config is disabled.  Hoist the #ifdef to the
top level so the real implementation and the empty stub are two clearly
separated definitions.

No functional change.

Signed-off-by: Ye Liu <ye.liu@linux.dev>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Reviewed-by: Vlastimil Babka (SUSE) <vbabka@kernel.org>
---
 mm/page_owner.c | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/mm/page_owner.c b/mm/page_owner.c
index 4e352941a6e2..fe2bf2274d8a 100644
--- a/mm/page_owner.c
+++ b/mm/page_owner.c
@@ -522,13 +522,13 @@ void pagetypeinfo_showmixedcount_print(struct seq_file *m,
 	seq_putc(m, '\n');
 }
 
+#ifdef CONFIG_MEMCG
 /*
  * Looking for memcg information and print it out
  */
 static inline int print_page_owner_memcg(char *kbuf, size_t count, int ret,
 					 struct page *page)
 {
-#ifdef CONFIG_MEMCG
 	unsigned long memcg_data;
 	struct mem_cgroup *memcg;
 	bool online;
@@ -556,10 +556,16 @@ static inline int print_page_owner_memcg(char *kbuf, size_t count, int ret,
 			name);
 out_unlock:
 	rcu_read_unlock();
-#endif /* CONFIG_MEMCG */
 
 	return ret;
 }
+#else
+static inline int print_page_owner_memcg(char *kbuf, size_t count, int ret,
+					 struct page *page)
+{
+	return ret;
+}
+#endif
 
 static ssize_t
 print_page_owner(char __user *buf, size_t count, unsigned long pfn,
-- 
2.43.0