bcachefs: per_cpu_sum()

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

fs/bcachefs/util.h

@@ -698,14 +698,19 @@ do {									\
 	}								\
 } while (0)
 
+#define per_cpu_sum(_p)							\
+({									\
+	typeof(*_p) _ret = 0;						\
+									\
+	int cpu;							\
+	for_each_possible_cpu(cpu)					\
+		_ret += *per_cpu_ptr(_p, cpu);				\
+	_ret;								\
+})
+
 static inline u64 percpu_u64_get(u64 __percpu *src)
 {
-	u64 ret = 0;
-	int cpu;
-
-	for_each_possible_cpu(cpu)
-		ret += *per_cpu_ptr(src, cpu);
-	return ret;
+	return per_cpu_sum(src);
 }
 
 static inline void percpu_u64_set(u64 __percpu *dst, u64 src)