diff --git a/include/linux/bitmap.h b/include/linux/bitmap.h
new file mode 100644
index 0000000..4a54ae0
--- /dev/null
+++ b/include/linux/bitmap.h
@@ -0,0 +1,23 @@
+// SPDX-License-Identifier: GPL-2.0+
+#ifndef __LINUX_BITMAP_H
+#define __LINUX_BITMAP_H
+
+#include <asm/types.h>
+#include <linux/types.h>
+#include <linux/bitops.h>
+
+#define small_const_nbits(nbits) \
+	(__builtin_constant_p(nbits) && (nbits) <= BITS_PER_LONG)
+
+static inline void bitmap_zero(unsigned long *dst, int nbits)
+{
+	if (small_const_nbits(nbits)) {
+		*dst = 0UL;
+	} else {
+		int len = BITS_TO_LONGS(nbits) * sizeof(unsigned long);
+
+		memset(dst, 0, len);
+	}
+}
+
+#endif /* __LINUX_BITMAP_H */