1 files changed, 134 insertions, 0 deletions
diff --git a/samples/rust/rust_debugfs_scoped.rs b/samples/rust/rust_debugfs_scoped.rs
new file mode 100644
index 000000000000..b0c4e76b123e
--- /dev/null
+++ b/samples/rust/rust_debugfs_scoped.rs
@@ -0,0 +1,134 @@
+// SPDX-License-Identifier: GPL-2.0
+
+// Copyright (C) 2025 Google LLC.
+
+//! Sample DebugFS exporting platform driver that demonstrates the use of
+//! `Scope::dir` to create a variety of files without the need to separately
+//! track them all.
+
+use core::sync::atomic::AtomicUsize;
+use kernel::debugfs::{Dir, Scope};
+use kernel::prelude::*;
+use kernel::sync::Mutex;
+use kernel::{c_str, new_mutex, str::CString};
+
+module! {
+    type: RustScopedDebugFs,
+    name: "rust_debugfs_scoped",
+    authors: ["Matthew Maurer"],
+    description: "Rust Scoped DebugFS usage sample",
+    license: "GPL",
+}
+
+fn remove_file_write(
+    mod_data: &ModuleData,
+    reader: &mut kernel::uaccess::UserSliceReader,
+) -> Result {
+    let mut buf = [0u8; 128];
+    if reader.len() >= buf.len() {
+        return Err(EINVAL);
+    }
+    let n = reader.len();
+    reader.read_slice(&mut buf[..n])?;
+
+    let s = core::str::from_utf8(&buf[..n]).map_err(|_| EINVAL)?.trim();
+    let nul_idx = s.len();
+    buf[nul_idx] = 0;
+    let to_remove = CStr::from_bytes_with_nul(&buf[..nul_idx + 1]).map_err(|_| EINVAL)?;
+    mod_data
+        .devices
+        .lock()
+        .retain(|device| device.name.as_bytes() != to_remove.as_bytes());
+    Ok(())
+}
+
+fn create_file_write(
+    mod_data: &ModuleData,
+    reader: &mut kernel::uaccess::UserSliceReader,
+) -> Result {
+    let mut buf = [0u8; 128];
+    if reader.len() > buf.len() {
+        return Err(EINVAL);
+    }
+    let n = reader.len();
+    reader.read_slice(&mut buf[..n])?;
+
+    let mut nums = KVec::new();
+
+    let s = core::str::from_utf8(&buf[..n]).map_err(|_| EINVAL)?.trim();
+    let mut items = s.split_whitespace();
+    let name_str = items.next().ok_or(EINVAL)?;
+    let name = CString::try_from_fmt(fmt!("{name_str}"))?;
+    let file_name = CString::try_from_fmt(fmt!("{name_str}"))?;
+    for sub in items {
+        nums.push(
+            AtomicUsize::new(sub.parse().map_err(|_| EINVAL)?),
+            GFP_KERNEL,
+        )?;
+    }
+
+    let scope = KBox::pin_init(
+        mod_data
+            .device_dir
+            .scope(DeviceData { name, nums }, &file_name, |dev_data, dir| {
+                for (idx, val) in dev_data.nums.iter().enumerate() {
+                    let Ok(name) = CString::try_from_fmt(fmt!("{idx}")) else {
+                        return;
+                    };
+                    dir.read_write_file(&name, val);
+                }
+            }),
+        GFP_KERNEL,
+    )?;
+    (*mod_data.devices.lock()).push(scope, GFP_KERNEL)?;
+
+    Ok(())
+}
+
+struct RustScopedDebugFs {
+    _data: Pin<KBox<Scope<ModuleData>>>,
+}
+
+#[pin_data]
+struct ModuleData {
+    device_dir: Dir,
+    #[pin]
+    devices: Mutex<KVec<Pin<KBox<Scope<DeviceData>>>>>,
+}
+
+impl ModuleData {
+    fn init(device_dir: Dir) -> impl PinInit<Self> {
+        pin_init! {
+            Self {
+                device_dir: device_dir,
+                devices <- new_mutex!(KVec::new())
+            }
+        }
+    }
+}
+
+struct DeviceData {
+    name: CString,
+    nums: KVec<AtomicUsize>,
+}
+
+fn init_control(base_dir: &Dir, dyn_dirs: Dir) -> impl PinInit<Scope<ModuleData>> + '_ {
+    base_dir.scope(
+        ModuleData::init(dyn_dirs),
+        c_str!("control"),
+        |data, dir| {
+            dir.write_only_callback_file(c_str!("create"), data, &create_file_write);
+            dir.write_only_callback_file(c_str!("remove"), data, &remove_file_write);
+        },
+    )
+}
+
+impl kernel::Module for RustScopedDebugFs {
+    fn init(_module: &'static kernel::ThisModule) -> Result<Self> {
+        let base_dir = Dir::new(c_str!("rust_scoped_debugfs"));
+        let dyn_dirs = base_dir.subdir(c_str!("dynamic"));
+        Ok(Self {
+            _data: KBox::pin_init(init_control(&base_dir, dyn_dirs), GFP_KERNEL)?,
+        })
+    }
+}