mm/mmap_lock: fix warning when CONFIG_TRACING is not defined

Fix the warning: [-Wunused-function]
mm/mmap_lock.c:157:20: warning: `get_mm_memcg_path' defined but not used
 static const char *get_mm_memcg_path(struct mm_struct *mm)
                    ^~~~~~~~~~~~~~~~~

Move get_mm_memcg_path() into #ifdef CONFIG_TRACING.

Link: https://lkml.kernel.org/r/20210531033426.74031-1-cuibixuan@huawei.com
Signed-off-by: Bixuan Cui <cuibixuan@huawei.com>
Acked-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Yang Shi <shy828301@gmail.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Dan Streetman <ddstreet@ieee.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: Michal Hocko <mhocko@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>

diff --git a/mm/mmap_lock.c b/mm/mmap_lock.c
index 03ee85c696ef03b78cdd84f6b7246db4f4028bea..29e99af7314464e8c5224f0f960f7c9087c72656 100644 (file)
--- a/mm/mmap_lock.c
+++ b/mm/mmap_lock.c
@@ -142,6 +142,37 @@ static inline void put_memcg_path_buf(void)
        rcu_read_unlock();
 }
 
+#define TRACE_MMAP_LOCK_EVENT(type, mm, ...)                                   \
+       do {                                                                   \
+               const char *memcg_path;                                        \
+               preempt_disable();                                             \
+               memcg_path = get_mm_memcg_path(mm);                            \
+               trace_mmap_lock_##type(mm,                                     \
+                                      memcg_path != NULL ? memcg_path : "",   \
+                                      ##__VA_ARGS__);                         \
+               if (likely(memcg_path != NULL))                                \
+                       put_memcg_path_buf();                                  \
+               preempt_enable();                                              \
+       } while (0)
+
+#else /* !CONFIG_MEMCG */
+
+int trace_mmap_lock_reg(void)
+{
+       return 0;
+}
+
+void trace_mmap_lock_unreg(void)
+{
+}
+
+#define TRACE_MMAP_LOCK_EVENT(type, mm, ...)                                   \
+       trace_mmap_lock_##type(mm, "", ##__VA_ARGS__)
+
+#endif /* CONFIG_MEMCG */
+
+#ifdef CONFIG_TRACING
+#ifdef CONFIG_MEMCG
 /*
  * Write the given mm_struct's memcg path to a percpu buffer, and return a
  * pointer to it. If the path cannot be determined, or no buffer was available
@@ -175,37 +206,8 @@ out_put:
 out:
        return buf;
 }
-
-#define TRACE_MMAP_LOCK_EVENT(type, mm, ...)                                   \
-       do {                                                                   \
-               const char *memcg_path;                                        \
-               preempt_disable();                                             \
-               memcg_path = get_mm_memcg_path(mm);                            \
-               trace_mmap_lock_##type(mm,                                     \
-                                      memcg_path != NULL ? memcg_path : "",   \
-                                      ##__VA_ARGS__);                         \
-               if (likely(memcg_path != NULL))                                \
-                       put_memcg_path_buf();                                  \
-               preempt_enable();                                              \
-       } while (0)
-
-#else /* !CONFIG_MEMCG */
-
-int trace_mmap_lock_reg(void)
-{
-       return 0;
-}
-
-void trace_mmap_lock_unreg(void)
-{
-}
-
-#define TRACE_MMAP_LOCK_EVENT(type, mm, ...)                                   \
-       trace_mmap_lock_##type(mm, "", ##__VA_ARGS__)
-
 #endif /* CONFIG_MEMCG */
 
-#ifdef CONFIG_TRACING
 /*
  * Trace calls must be in a separate file, as otherwise there's a circular
  * dependency between linux/mmap_lock.h and trace/events/mmap_lock.h.