rust: add bindings for bitops.h

Makes atomic set_bit and clear_bit inline functions as well as the
non-atomic variants __set_bit and __clear_bit available to Rust.
Adds a new MAINTAINERS section BITOPS API BINDINGS [RUST].

Suggested-by: Alice Ryhl <aliceryhl@google.com>
Suggested-by: Yury Norov <yury.norov@gmail.com>
Signed-off-by: Burak Emir <bqe@google.com>
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Acked-by: Yury Norov (NVIDIA) <yury.norov@gmail.com>
Signed-off-by: Yury Norov (NVIDIA) <yury.norov@gmail.com>

MAINTAINERS

@@ -4316,6 +4316,11 @@ F:	include/linux/bitops.h
 F:	lib/test_bitops.c
 F:	tools/*/bitops*
 
+BITOPS API BINDINGS [RUST]
+M:	Yury Norov <yury.norov@gmail.com>
+S:	Maintained
+F:	rust/helpers/bitops.c
+
 BLINKM RGB LED DRIVER
 M:	Jan-Simon Moeller <jansimon.moeller@gmx.de>
 S:	Maintained

rust/helpers/bitops.c

@@ -0,0 +1,23 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/bitops.h>
+
+void rust_helper___set_bit(unsigned long nr, unsigned long *addr)
+{
+	__set_bit(nr, addr);
+}
+
+void rust_helper___clear_bit(unsigned long nr, unsigned long *addr)
+{
+	__clear_bit(nr, addr);
+}
+
+void rust_helper_set_bit(unsigned long nr, volatile unsigned long *addr)
+{
+	set_bit(nr, addr);
+}
+
+void rust_helper_clear_bit(unsigned long nr, volatile unsigned long *addr)
+{
+	clear_bit(nr, addr);
+}

rust/helpers/helpers.c

@@ -9,6 +9,7 @@
 
 #include "auxiliary.c"
 #include "bitmap.c"
+#include "bitops.c"
 #include "blk.c"
 #include "bug.c"
 #include "build_assert.c"