From: Andreas Hindborg <a.hindborg@kernel.org>
Date: Thu, 12 Jun 2025 13:09:44 +0000 (+0200)
Subject: rust: types: require `ForeignOwnable::into_foreign` return non-null
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=a68a6bef0e75fb9e5aea1399d8538f4e3584dab1;p=thirdparty%2Fkernel%2Flinux.git

rust: types: require `ForeignOwnable::into_foreign` return non-null

The intended implementations of `ForeignOwnable` will not return null
pointers from `into_foreign`, as this would render the implementation of
`try_from_foreign` useless. Current users of `ForeignOwnable` rely on
`into_foreign` returning non-null pointers. So require `into_foreign` to
return non-null pointers.

Suggested-by: Benno Lossin <lossin@kernel.org>
Suggested-by: Alice Ryhl <aliceryhl@google.com>
Signed-off-by: Andreas Hindborg <a.hindborg@kernel.org>
Reviewed-by: Benno Lossin <lossin@kernel.org>
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Link: https://lore.kernel.org/r/20250612-pointed-to-v3-2-b009006d86a1@kernel.org
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
---

diff --git a/rust/kernel/types.rs b/rust/kernel/types.rs
index c156808a78d3c..63a2559a545f7 100644
--- a/rust/kernel/types.rs
+++ b/rust/kernel/types.rs
@@ -43,6 +43,7 @@ pub unsafe trait ForeignOwnable: Sized {
     /// # Guarantees
     ///
     /// - Minimum alignment of returned pointer is [`Self::FOREIGN_ALIGN`].
+    /// - The returned pointer is not null.
     ///
     /// [`from_foreign`]: Self::from_foreign
     /// [`try_from_foreign`]: Self::try_from_foreign