Starting with Rust 1.99.0 (expected 2026-10-01), the
`Atomic*::fetch_update` method is deprecated, with the compiler suggesting
the `try_update` alias instead:

    error: use of deprecated method `core::sync::atomic::Atomic::<u64>::fetch_update`: renamed to `try_update` for consistency
       --> rust/kernel/block/mq/request.rs:206:22
        |
    206 |     let old = target.fetch_update(Ordering::Relaxed, Ordering::Relaxed, |x| Some(op(x)));
        |                      ^^^^^^^^^^^^
        |
        = note: `-D deprecated` implied by `-D warnings`
        = help: to override `-D warnings` add `#[allow(deprecated)]`
    help: replace the use of the deprecated method
        |
    206 -     let old = target.fetch_update(Ordering::Relaxed, Ordering::Relaxed, |x| Some(op(x)));
    206 +     let old = target.try_update(Ordering::Relaxed, Ordering::Relaxed, |x| Some(op(x)));
        |

The deprecation was added in Rust 1.95.0 [1], but only triggers starting
with Rust 1.99.0.

However, we cannot use the alias since our minimum in 6.12.y is Rust
1.78.0 -- `try_update` was added in Rust 1.86.0 [2].

Thus just allow the lint.

Cc: Andreas Hindborg <a.hindborg@kernel.org>
Cc: Boqun Feng <boqun@kernel.org>
Cc: Jens Axboe <axboe@kernel.dk>
Link: https://github.com/rust-lang/rust/pull/148590 [1]
Link: https://github.com/rust-lang/rust/pull/133829 [2]
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

[ Upstream commit 28e848386b92645f93b9f2fdba5882c3ca7fb3e2 ]

Fix several issues with rustdoc formatting for the
`kernel::block::mq::Request` module, in particular:

  - An ordered list not rendering correctly, fixed by using numbers
    prefixes instead of letters.

  - Code snippets formatted as regular text, fixed by wrapping the
    code with `back-ticks`.

  - References to types missing intra-doc links, fixed by wrapping the
    types with [square brackets].

Reported-by: Miguel Ojeda <ojeda@kernel.org>
Closes: https://github.com/Rust-for-Linux/linux/issues/1108
Signed-off-by: Francesco Zardi <frazar00@gmail.com>
Acked-by: Andreas Hindborg <a.hindborg@kernel.org>
Fixes: 3253aba3408a ("rust: block: introduce `kernel::block::mq` module")
Link: https://lore.kernel.org/r/20240903173027.16732-3-frazar00@gmail.com
[ Added an extra intra-doc link. Took the chance to add some periods
  for consistency. Reworded slightly. - Miguel ]
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

Add initial abstractions for working with blk-mq.

This patch is a maintained, refactored subset of code originally published
by Wedson Almeida Filho <wedsonaf@gmail.com> [1].

[1] https://github.com/wedsonaf/linux/tree/f2cfd2fe0e2ca4e90994f96afe268bbd4382a891/rust/kernel/blk/mq.rs

Cc: Wedson Almeida Filho <wedsonaf@gmail.com>
Signed-off-by: Andreas Hindborg <a.hindborg@samsung.com>
Reviewed-by: Benno Lossin <benno.lossin@proton.me>
Link: https://lore.kernel.org/r/20240611114551.228679-2-nmi@metaspace.dk
Signed-off-by: Jens Axboe <axboe@kernel.dk>