linux-kernel - [PATCH v2 1/4] rust: device: implement Device::parent()

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20250320222823.16509-2-dakr@kernel.org>
Date: Thu, 20 Mar 2025 23:27:43 +0100
From: Danilo Krummrich <dakr@...nel.org>
To: bhelgaas@...gle.com,
	gregkh@...uxfoundation.org,
	rafael@...nel.org,
	ojeda@...nel.org,
	alex.gaynor@...il.com,
	boqun.feng@...il.com,
	gary@...yguo.net,
	bjorn3_gh@...tonmail.com,
	benno.lossin@...ton.me,
	a.hindborg@...nel.org,
	aliceryhl@...gle.com,
	tmgross@...ch.edu
Cc: linux-pci@...r.kernel.org,
	rust-for-linux@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	Danilo Krummrich <dakr@...nel.org>
Subject: [PATCH v2 1/4] rust: device: implement Device::parent()

Device::parent() returns a reference to the device' parent device, if
any.

Reviewed-by: Alice Ryhl <aliceryhl@...gle.com>
Signed-off-by: Danilo Krummrich <dakr@...nel.org>
---
 rust/kernel/device.rs | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/rust/kernel/device.rs b/rust/kernel/device.rs
index 21b343a1dc4d..f6bdc2646028 100644
--- a/rust/kernel/device.rs
+++ b/rust/kernel/device.rs
@@ -65,6 +65,21 @@ pub(crate) fn as_raw(&self) -> *mut bindings::device {
         self.0.get()
     }
 
+    /// Returns a reference to the parent device, if any.
+    pub fn parent<'a>(&self) -> Option<&'a Self> {
+        // SAFETY:
+        // - By the type invariant `self.as_raw()` is always valid.
+        // - The parent device is only ever set at device creation.
+        let parent = unsafe { (*self.as_raw()).parent };
+
+        if parent.is_null() {
+            None
+        } else {
+            // SAFETY: Since `parent` is not NULL, it must be a valid pointer to a `struct device`.
+            Some(unsafe { Self::as_ref(parent) })
+        }
+    }
+
     /// Convert a raw C `struct device` pointer to a `&'a Device`.
     ///
     /// # Safety
-- 
2.48.1