rust: helpers: Add bindings/wrappers for dma_resv_lock

This is just for basic usage in the DRM shmem abstractions for implied
locking, not intended as a full DMA Reservation abstraction yet.

Cc: Sumit Semwal <sumit.semwal@linaro.org>
Cc: Christian König <christian.koenig@amd.com>
Signed-off-by: Asahi Lina <lina+kernel@asahilina.net>
Signed-off-by: Daniel Almeida <daniel.almeida@collabora.com>
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Signed-off-by: Lyude Paul <lyude@redhat.com>
Reviewed-by: Janne Grunau <j@jannau.net>
Reviewed-by: Daniel Almeida <daniel.almeida@collabora.com>
Acked-by: David Airlie <airlied@gmail.com>
Signed-off-by: Alice Ryhl <aliceryhl@google.com>
Link: https://patch.msgid.link/20260320-gpuvm-rust-v5-2-76fd44f17a87@google.com
Signed-off-by: Danilo Krummrich <dakr@kernel.org>

MAINTAINERS

@@ -7534,6 +7534,7 @@ F:	include/linux/*fence.h
 F:	include/linux/dma-buf.h
 F:	include/linux/dma-buf/
 F:	include/linux/dma-resv.h
+F:	rust/helpers/dma-resv.c
 K:	\bdma_(?:buf|fence|resv)\b
 
 DMA GENERIC OFFLOAD ENGINE SUBSYSTEM

rust/bindings/bindings_helper.h

@@ -52,6 +52,7 @@
 #include <linux/device/faux.h>
 #include <linux/dma-direction.h>
 #include <linux/dma-mapping.h>
+#include <linux/dma-resv.h>
 #include <linux/errname.h>
 #include <linux/ethtool.h>
 #include <linux/fdtable.h>

rust/helpers/dma-resv.c

@@ -0,0 +1,14 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/dma-resv.h>
+
+__rust_helper
+int rust_helper_dma_resv_lock(struct dma_resv *obj, struct ww_acquire_ctx *ctx)
+{
+	return dma_resv_lock(obj, ctx);
+}
+
+__rust_helper void rust_helper_dma_resv_unlock(struct dma_resv *obj)
+{
+	dma_resv_unlock(obj);
+}

rust/helpers/helpers.c

@@ -28,6 +28,7 @@
 #include "cred.c"
 #include "device.c"
 #include "dma.c"
+#include "dma-resv.c"
 #include "drm.c"
 #include "err.c"
 #include "irq.c"