[PATCH RFC 2/3] bcachefs: create framework for Rust bindings

[PATCH RFC 2/3] bcachefs: create framework for Rust bindings

[Thomas Bertschinger]

This adds infrastructure for Rust bindings, generated by bindgen, for
bcachefs internal use. The Rust code is only enabled when a new config
option, BCACHEFS_RUST, is defined. This option depends on RUST.

This change does not generate any bindings; future patches will use the
framework introduced here to add Rust code to bcachefs.

Signed-off-by: Thomas Bertschinger <tahbertschinger@gmail.com>
---
 fs/bcachefs/.gitignore                 | 3 +++
 fs/bcachefs/Kconfig                    | 6 ++++++
 fs/bcachefs/Makefile                   | 9 +++++++++
 fs/bcachefs/bindgen_parameters         | 5 +++++
 fs/bcachefs/bindings/bindings_helper.h | 3 +++
 fs/bcachefs/bindings/mod.rs            | 3 +++
 6 files changed, 29 insertions(+)
 create mode 100644 fs/bcachefs/.gitignore
 create mode 100644 fs/bcachefs/bindgen_parameters
 create mode 100644 fs/bcachefs/bindings/bindings_helper.h
 create mode 100644 fs/bcachefs/bindings/mod.rs

diff --git a/fs/bcachefs/.gitignore b/fs/bcachefs/.gitignore
new file mode 100644
index 000000000000..35be43f02195
--- /dev/null
+++ b/fs/bcachefs/.gitignore
@@ -0,0 +1,3 @@
+# SPDX-License-Identifier: GPL-2.0-only
+
+bcachefs_generated.rs
diff --git a/fs/bcachefs/Kconfig b/fs/bcachefs/Kconfig
index 5cdfef3b551a..6d40669dca00 100644
--- a/fs/bcachefs/Kconfig
+++ b/fs/bcachefs/Kconfig
@@ -33,6 +33,12 @@ config BCACHEFS_QUOTA
 	depends on BCACHEFS_FS
 	select QUOTACTL
 
+config BCACHEFS_RUST
+	bool "bcachefs Rust support"
+	depends on BCACHEFS_FS && RUST
+	help
+	This enables the internal Rust bindings for bcachefs.
+
 config BCACHEFS_ERASURE_CODING
 	bool "bcachefs erasure coding (RAID5/6) support (EXPERIMENTAL)"
 	depends on BCACHEFS_FS
diff --git a/fs/bcachefs/Makefile b/fs/bcachefs/Makefile
index 1a05cecda7cc..3f209511149c 100644
--- a/fs/bcachefs/Makefile
+++ b/fs/bcachefs/Makefile
@@ -89,4 +89,13 @@ bcachefs-y		:=	\
 	varint.o		\
 	xattr.o
 
+always-$(CONFIG_BCACHEFS_RUST)		+= bindings/bcachefs_generated.rs
+
+$(obj)/bindings/bcachefs_generated.rs: private bindgen_target_flags = \
+    $(shell grep -Ev '^#|^$$' $(srctree)/$(src)/bindgen_parameters)
+
+$(obj)/bindings/bcachefs_generated.rs: $(src)/bindings/bindings_helper.h  \
+	$(src)/bindgen_parameters FORCE
+	$(call if_changed_dep,bindgen)
+
 obj-$(CONFIG_MEAN_AND_VARIANCE_UNIT_TEST)   += mean_and_variance_test.o
diff --git a/fs/bcachefs/bindgen_parameters b/fs/bcachefs/bindgen_parameters
new file mode 100644
index 000000000000..547212bebd6e
--- /dev/null
+++ b/fs/bcachefs/bindgen_parameters
@@ -0,0 +1,5 @@
+# SPDX-License-Identifier: GPL-2.0
+
+--allowlist-function ''
+--allowlist-type ''
+--allowlist-var ''
diff --git a/fs/bcachefs/bindings/bindings_helper.h b/fs/bcachefs/bindings/bindings_helper.h
new file mode 100644
index 000000000000..f8bef3676f71
--- /dev/null
+++ b/fs/bcachefs/bindings/bindings_helper.h
@@ -0,0 +1,3 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+#include "../bcachefs.h"
diff --git a/fs/bcachefs/bindings/mod.rs b/fs/bcachefs/bindings/mod.rs
new file mode 100644
index 000000000000..19a3ae3c63c6
--- /dev/null
+++ b/fs/bcachefs/bindings/mod.rs
@@ -0,0 +1,3 @@
+// SPDX-License-Identifier: GPL-2.0
+
+include!("bcachefs_generated.rs");
-- 
2.43.0