diff --git a/include/linux/compiler_attributes.h b/include/linux/compiler_attributes.h
index ea5e04e75845..c043b8d2b17b 100644
--- a/include/linux/compiler_attributes.h
+++ b/include/linux/compiler_attributes.h
@@ -210,6 +210,12 @@
 # define fallthrough                    do {} while (0)  /* fallthrough */
 #endif
 
+/*
+ * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html#Common-Function-Attributes
+ * clang: https://clang.llvm.org/docs/AttributeReference.html#flatten
+ */
+# define __flatten			__attribute__((flatten))
+
 /*
  * Note the missing underscores.
  *
diff --git a/mm/percpu.c b/mm/percpu.c
index 80f8f885a990..6596a0a4286e 100644
--- a/mm/percpu.c
+++ b/mm/percpu.c
@@ -2663,7 +2663,7 @@ early_param("percpu_alloc", percpu_alloc_setup);
  * On success, pointer to the new allocation_info is returned.  On
  * failure, ERR_PTR value is returned.
  */
-static struct pcpu_alloc_info * __init pcpu_build_alloc_info(
+static struct pcpu_alloc_info * __init __flatten pcpu_build_alloc_info(
 				size_t reserved_size, size_t dyn_size,
 				size_t atom_size,
 				pcpu_fc_cpu_distance_fn_t cpu_distance_fn)