1 files changed, 23 insertions, 0 deletions
diff --git a/scripts/atomic/fallbacks/fetch_add_unless b/scripts/atomic/fallbacks/fetch_add_unless
new file mode 100755
index 000000000..0e0b9aef1
--- /dev/null
+++ b/scripts/atomic/fallbacks/fetch_add_unless
@@ -0,0 +1,23 @@
+cat << EOF
+/**
+ * ${arch}${atomic}_fetch_add_unless - add unless the number is already a given value
+ * @v: pointer of type ${atomic}_t
+ * @a: the amount to add to v...
+ * @u: ...unless v is equal to u.
+ *
+ * Atomically adds @a to @v, so long as @v was not already @u.
+ * Returns original value of @v
+ */
+static __always_inline ${int}
+${arch}${atomic}_fetch_add_unless(${atomic}_t *v, ${int} a, ${int} u)
+{
+	${int} c = ${arch}${atomic}_read(v);
+
+	do {
+		if (unlikely(c == u))
+			break;
+	} while (!${arch}${atomic}_try_cmpxchg(v, &c, c + a));
+
+	return c;
+}
+EOF