[PATCH v2 5/5] samples: rust: add in-place initialisation sample

[Wedson Almeida Filho <wedsonaf@gmail.com>]

From: Wedson Almeida Filho <walmeida@microsoft.com>

This is a modified version of rust_minimal that is initialised in-place
and has a mutex.

Signed-off-by: Wedson Almeida Filho <walmeida@microsoft.com>
---
 samples/rust/Kconfig         | 11 +++++++++
 samples/rust/Makefile        |  1 +
 samples/rust/rust_inplace.rs | 44 ++++++++++++++++++++++++++++++++++++
 3 files changed, 56 insertions(+)
 create mode 100644 samples/rust/rust_inplace.rs

diff --git a/samples/rust/Kconfig b/samples/rust/Kconfig
index b0f74a81c8f9..59f44a8b6958 100644
--- a/samples/rust/Kconfig
+++ b/samples/rust/Kconfig
@@ -20,6 +20,17 @@ config SAMPLE_RUST_MINIMAL
 
 	  If unsure, say N.
 
+config SAMPLE_RUST_INPLACE
+	tristate "Minimal in-place"
+	help
+	  This option builds the Rust minimal module with in-place
+	  initialisation.
+
+	  To compile this as a module, choose M here:
+	  the module will be called rust_inplace.
+
+	  If unsure, say N.
+
 config SAMPLE_RUST_PRINT
 	tristate "Printing macros"
 	help
diff --git a/samples/rust/Makefile b/samples/rust/Makefile
index 03086dabbea4..791fc18180e9 100644
--- a/samples/rust/Makefile
+++ b/samples/rust/Makefile
@@ -1,6 +1,7 @@
 # SPDX-License-Identifier: GPL-2.0
 
 obj-$(CONFIG_SAMPLE_RUST_MINIMAL)		+= rust_minimal.o
+obj-$(CONFIG_SAMPLE_RUST_INPLACE)		+= rust_inplace.o
 obj-$(CONFIG_SAMPLE_RUST_PRINT)			+= rust_print.o
 
 subdir-$(CONFIG_SAMPLE_RUST_HOSTPROGS)		+= hostprogs
diff --git a/samples/rust/rust_inplace.rs b/samples/rust/rust_inplace.rs
new file mode 100644
index 000000000000..0410e97a689f
--- /dev/null
+++ b/samples/rust/rust_inplace.rs
@@ -0,0 +1,44 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Rust minimal in-place sample.
+
+use kernel::prelude::*;
+use kernel::{new_mutex, sync::Mutex};
+
+module! {
+    type: RustInPlace,
+    name: "rust_inplace",
+    author: "Rust for Linux Contributors",
+    description: "Rust minimal in-place sample",
+    license: "GPL",
+}
+
+#[pin_data(PinnedDrop)]
+struct RustInPlace {
+    #[pin]
+    numbers: Mutex<Vec<i32>>,
+}
+
+impl kernel::InPlaceModule for RustInPlace {
+    fn init(_module: &'static ThisModule) -> impl PinInit<Self, Error> {
+        pr_info!("Rust in-place minimal sample (init)\n");
+        pr_info!("Am I built-in? {}\n", !cfg!(MODULE));
+        try_pin_init!(Self {
+            numbers <- {
+                let mut numbers = Vec::new();
+                numbers.push(72, GFP_KERNEL)?;
+                numbers.push(108, GFP_KERNEL)?;
+                numbers.push(200, GFP_KERNEL)?;
+                new_mutex!(numbers)
+            },
+        })
+    }
+}
+
+#[pinned_drop]
+impl PinnedDrop for RustInPlace {
+    fn drop(self: Pin<&mut Self>) {
+        pr_info!("My numbers are {:?}\n", *self.numbers.lock());
+        pr_info!("Rust minimal inplace sample (exit)\n");
+    }
+}
-- 
2.34.1