diff --git a/sys/compat/linuxkpi/common/include/asm/atomic-long.h b/sys/compat/linuxkpi/common/include/asm/atomic-long.h
--- a/sys/compat/linuxkpi/common/include/asm/atomic-long.h
+++ b/sys/compat/linuxkpi/common/include/asm/atomic-long.h
@@ -41,7 +41,7 @@
 } atomic_long_t;
 
 #define	atomic_long_add(i, v)		atomic_long_add_return((i), (v))
-#define	atomic_long_sub(i, v)		atomic_long_add_return(-(i), (v))
+#define	atomic_long_sub(i, v)		atomic_long_sub_return((i), (v))
 #define	atomic_long_inc_return(v)	atomic_long_add_return(1, (v))
 #define	atomic_long_inc_not_zero(v)	atomic_long_add_unless((v), 1, 0)
 
@@ -51,6 +51,12 @@
 	return i + atomic_fetchadd_long(&v->counter, i);
 }
 
+static inline long
+atomic_long_sub_return(long i, atomic_long_t *v)
+{
+	return atomic_fetchadd_long(&v->counter, -i) - i;
+}
+
 static inline void
 atomic_long_set(atomic_long_t *v, long i)
 {