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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. Intended to land through alloc-next under the RUST [ALLOC] entry. Signed-off-by: Alice Ryhl --- Changes in v2: - Reword guarantee on `const MIN_ALIGN`. - Change formatting of if/else in kbox.rs. - Rebase on v6.17-rc1. - Link to v1: https://lore.kernel.org/r/20250715-align-min-allocator-v1-0-3e1b2a5516c0@google.com --- 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 | 13 +++++++++---- rust/kernel/sync/arc.rs | 6 +++--- 4 files changed, 28 insertions(+), 7 deletions(-) --- base-commit: 062b3e4a1f880f104a8d4b90b767788786aa7b78 change-id: 20250715-align-min-allocator-b31aee53cbda Best regards, -- Alice Ryhl