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a=openpgp; fpr=49F6C1FAA74960F43A5B86A1EE7A392FDE96209F X-Developer-Signature: v=1; a=openpgp-sha256; l=1282; i=aliceryhl@google.com; h=from:subject:message-id; bh=s5VZOQklE5Yi2oixqgin8j2KWQ7Dx7YJloRvpywwTVg=; b=owEBbQKS/ZANAwAKAQRYvu5YxjlGAcsmYgBodlvAW1uGuI8VV3ZaJchh2qeFswg3h6xxEFN0n suh4FlodWKJAjMEAAEKAB0WIQSDkqKUTWQHCvFIvbIEWL7uWMY5RgUCaHZbwAAKCRAEWL7uWMY5 RrhVD/9DIS3lODYHGPRiJdnhlQFerkUldW6WwGQGSQVZyaqFAx+mEPq7UBTzvVukZqQzzSNkV0A MY4NiNOXuwIeZ5Kk16GUQvHIIwM/8ZZ4tBnDNbiR358aVa2lS0HphIGuarJzAZvna/pGe/m+xTj ED5z3d6N3n1oxYYKW5mRISfd1jF8ewf4LbCybuwlqdLRqE6OozzWsYP6SVpZuuFkBFmu3MCqLQe jfWa8W2yhYjesdbo7dbW6ZF984uVRUG8LQwQcWVWiN91mDXpS8lhlKyzAAObHsfQqD2okMcKYR/ ggr2MpmwfPCzS8AUVCkW+YYw5xg4PljuvobVyPj4BD9BeOCQ8pn3N17mhKzqKk1+P8zpSls83Qv HWhKZ20SYCs5tnFzu7tdt02bXoPH7wnPJKoVrYTVDeYR5/wVxvRFMgKtBSoqxNexAeFFj+dh+EA ED6D4fU4QsgjoeUrnk1dWz7cI774/JaPygvPfWBQFs8NM9Co0Wg7erQFxS7Ffadte0Yevg694+L EPT1IXDUU2ebPDH1RVfrGknLZV7IM7kg9Kql3zwd5I2LQzNQqiwL4FUCuPzvIybwlAKejVbEXs7 kfrXxQ03tcjjar+PJmF9nAzAkpFi8JfDw8O6pOZe9kHJ1sHubj9/svP/x5891LyHrH+1RvEVtns bUrSKkt5laGpPfg== X-Mailer: b4 0.14.2 Message-ID: <20250715-align-min-allocator-v1-0-3e1b2a5516c0@google.com> Subject: [PATCH 0/2] Take ARCH_KMALLOC_MINALIGN into account for build-time XArray check From: Alice Ryhl To: Lorenzo Stoakes , "Liam R. Howlett" , Andrew Morton , Danilo Krummrich , Matthew Wilcox , Tamir Duberstein , Andreas Hindborg , Miguel Ojeda Cc: Boqun Feng , Gary Guo , "=?utf-8?q?Bj=C3=B6rn_Roy_Baron?=" , Benno Lossin , Trevor Gross , linux-mm@kvack.org, rust-for-linux@vger.kernel.org, linux-kernel@vger.kernel.org, Alice Ryhl Content-Type: text/plain; charset="utf-8" The Rust bindings for XArray include a build-time check to ensure that you can only use the XArray with pointers that are 4-byte aligned. Because of that, there is currently a build failure if you attempt to create an XArray> where T is a 1-byte or 2-byte aligned type. However, this error is incorrect as KBox<_> is guaranteed to be a pointer that comes from kmalloc, and kmalloc always produces pointers that are at least 4-byte aligned. To fix this, we augment the compile-time logic that computes the alignment of KBox<_> to take the minimum alignment of its allocator into account. This series is based on top of rust-next. Signed-off-by: Alice Ryhl --- Alice Ryhl (2): rust: alloc: specify the minimum alignment of each allocator rust: alloc: take the allocator into account for FOREIGN_ALIGN rust/kernel/alloc.rs | 8 ++++++++ rust/kernel/alloc/allocator.rs | 8 ++++++++ rust/kernel/alloc/kbox.rs | 15 +++++++++++---- rust/kernel/sync/arc.rs | 6 +++--- 4 files changed, 30 insertions(+), 7 deletions(-) --- base-commit: a68a6bef0e75fb9e5aea1399d8538f4e3584dab1 change-id: 20250715-align-min-allocator-b31aee53cbda Best regards, -- Alice Ryhl