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7f201ca18c
Adds a `debugfs::Dir` type that can be used to create and remove DebugFS directories. The `Dir` handle automatically cleans up the directory on `Drop`. Signed-off-by: Matthew Maurer <mmaurer@google.com> Tested-by: Dirk Behme <dirk.behme@de.bosch.com> Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Link: https://lore.kernel.org/r/20250904-debugfs-rust-v11-1-7d12a165685a@google.com Signed-off-by: Danilo Krummrich <dakr@kernel.org>
82 lines
2.6 KiB
Rust
82 lines
2.6 KiB
Rust
// SPDX-License-Identifier: GPL-2.0
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// Copyright (C) 2025 Google LLC.
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//! DebugFS Abstraction
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//!
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//! C header: [`include/linux/debugfs.h`](srctree/include/linux/debugfs.h)
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// When DebugFS is disabled, many parameters are dead. Linting for this isn't helpful.
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#![cfg_attr(not(CONFIG_DEBUG_FS), allow(unused_variables))]
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#[cfg(CONFIG_DEBUG_FS)]
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use crate::prelude::*;
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use crate::str::CStr;
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#[cfg(CONFIG_DEBUG_FS)]
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use crate::sync::Arc;
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#[cfg(CONFIG_DEBUG_FS)]
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mod entry;
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#[cfg(CONFIG_DEBUG_FS)]
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use entry::Entry;
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/// Owning handle to a DebugFS directory.
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///
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/// The directory in the filesystem represented by [`Dir`] will be removed when handle has been
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/// dropped *and* all children have been removed.
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// If we have a parent, we hold a reference to it in the `Entry`. This prevents the `dentry`
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// we point to from being cleaned up if our parent `Dir`/`Entry` is dropped before us.
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//
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// The `None` option indicates that the `Arc` could not be allocated, so our children would not be
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// able to refer to us. In this case, we need to silently fail. All future child directories/files
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// will silently fail as well.
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#[derive(Clone)]
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pub struct Dir(#[cfg(CONFIG_DEBUG_FS)] Option<Arc<Entry>>);
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impl Dir {
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/// Create a new directory in DebugFS. If `parent` is [`None`], it will be created at the root.
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fn create(name: &CStr, parent: Option<&Dir>) -> Self {
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#[cfg(CONFIG_DEBUG_FS)]
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{
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let parent_entry = match parent {
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// If the parent couldn't be allocated, just early-return
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Some(Dir(None)) => return Self(None),
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Some(Dir(Some(entry))) => Some(entry.clone()),
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None => None,
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};
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Self(
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// If Arc creation fails, the `Entry` will be dropped, so the directory will be
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// cleaned up.
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Arc::new(Entry::dynamic_dir(name, parent_entry), GFP_KERNEL).ok(),
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)
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}
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#[cfg(not(CONFIG_DEBUG_FS))]
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Self()
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}
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/// Create a new directory in DebugFS at the root.
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///
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/// # Examples
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///
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/// ```
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/// # use kernel::c_str;
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/// # use kernel::debugfs::Dir;
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/// let debugfs = Dir::new(c_str!("parent"));
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/// ```
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pub fn new(name: &CStr) -> Self {
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Dir::create(name, None)
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}
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/// Creates a subdirectory within this directory.
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///
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/// # Examples
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///
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/// ```
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/// # use kernel::c_str;
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/// # use kernel::debugfs::Dir;
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/// let parent = Dir::new(c_str!("parent"));
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/// let child = parent.subdir(c_str!("child"));
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/// ```
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pub fn subdir(&self, name: &CStr) -> Self {
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Dir::create(name, Some(self))
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}
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}
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