mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/herbert/cryptodev-2.6.git
synced 2026-04-23 05:56:14 -04:00
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>
62 lines
2.1 KiB
Rust
62 lines
2.1 KiB
Rust
// SPDX-License-Identifier: GPL-2.0
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// Copyright (C) 2025 Google LLC.
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use crate::str::CStr;
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use crate::sync::Arc;
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/// Owning handle to a DebugFS entry.
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///
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/// # Invariants
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///
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/// The wrapped pointer will always be `NULL`, an error, or an owned DebugFS `dentry`.
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pub(crate) struct Entry {
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entry: *mut bindings::dentry,
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// If we were created with an owning parent, this is the keep-alive
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_parent: Option<Arc<Entry>>,
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}
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// SAFETY: [`Entry`] is just a `dentry` under the hood, which the API promises can be transferred
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// between threads.
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unsafe impl Send for Entry {}
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// SAFETY: All the C functions we call on the `dentry` pointer are threadsafe.
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unsafe impl Sync for Entry {}
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impl Entry {
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pub(crate) fn dynamic_dir(name: &CStr, parent: Option<Arc<Self>>) -> Self {
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let parent_ptr = match &parent {
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Some(entry) => entry.as_ptr(),
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None => core::ptr::null_mut(),
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};
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// SAFETY: The invariants of this function's arguments ensure the safety of this call.
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// * `name` is a valid C string by the invariants of `&CStr`.
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// * `parent_ptr` is either `NULL` (if `parent` is `None`), or a pointer to a valid
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// `dentry` by our invariant. `debugfs_create_dir` handles `NULL` pointers correctly.
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let entry = unsafe { bindings::debugfs_create_dir(name.as_char_ptr(), parent_ptr) };
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Entry {
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entry,
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_parent: parent,
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}
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}
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/// Returns the pointer representation of the DebugFS directory.
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///
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/// # Guarantees
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///
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/// Due to the type invariant, the value returned from this function will always be an error
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/// code, NULL, or a live DebugFS directory. If it is live, it will remain live at least as
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/// long as this entry lives.
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pub(crate) fn as_ptr(&self) -> *mut bindings::dentry {
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self.entry
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}
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}
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impl Drop for Entry {
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fn drop(&mut self) {
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// SAFETY: `debugfs_remove` can take `NULL`, error values, and legal DebugFS dentries.
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// `as_ptr` guarantees that the pointer is of this form.
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unsafe { bindings::debugfs_remove(self.as_ptr()) }
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}
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}
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