From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from lindbergh.monkeyblade.net (lindbergh.monkeyblade.net [23.128.96.19]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 0C083156D3 for ; Wed, 19 Jul 2023 14:21:34 +0000 (UTC) Received: from mail-4322.protonmail.ch (mail-4322.protonmail.ch [185.70.43.22]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6093D270E for ; Wed, 19 Jul 2023 07:21:05 -0700 (PDT) Date: Wed, 19 Jul 2023 14:20:57 +0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=proton.me; s=protonmail; t=1689776463; x=1690035663; bh=ocaw+Jg23eMbqrHzK2iWdBrvi4VvFs/SPBCP4KfLQJI=; h=Date:To:From:Cc:Subject:Message-ID:In-Reply-To:References: Feedback-ID:From:To:Cc:Date:Subject:Reply-To:Feedback-ID: Message-ID:BIMI-Selector; b=gK1ISIfeWnjFtMpoaYRH7GnrQ1vT8LMld6UrLQmh9V7bcBAA6Bn2dtmYxpZrTSclX oT7nEDYzQXAJMcvgCJ3c1GPr5LVwaiYcvuZeAPgbWWlXEyZNTQNK1t632sK8JtBm89 AsPMCN4Z3uN/lJR9oDe9RYcluSFZy696clmyjDdgfHZX7AExnKP5pqooI2+zDO9iLY oZG0w0GZ48nKTfoo8BKV/2dvfMsZx7Z3SngYAydmsNQ7Rmzf8woa3OP2f9BwUMxI2q Dt0v5ZK1F11b7pL5nf9sFhV5e61Y7Ub0HeMpTKtPnpY6Lr93AoDDwYBegH2d/MJGJZ IbVZL2LIyggnQ== To: Miguel Ojeda , Wedson Almeida Filho , Alex Gaynor From: Benno Lossin Cc: Boqun Feng , Gary Guo , =?utf-8?Q?Bj=C3=B6rn_Roy_Baron?= , Benno Lossin , Alice Ryhl , Andreas Hindborg , rust-for-linux@vger.kernel.org, linux-kernel@vger.kernel.org, Asahi Lina Subject: [PATCH v2 07/12] rust: init: Add functions to create array initializers Message-ID: <20230719141918.543938-8-benno.lossin@proton.me> In-Reply-To: <20230719141918.543938-1-benno.lossin@proton.me> References: <20230719141918.543938-1-benno.lossin@proton.me> Feedback-ID: 71780778:user:proton Precedence: bulk X-Mailing-List: rust-for-linux@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable X-Spam-Status: No, score=-2.1 required=5.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,RCVD_IN_DNSWL_BLOCKED, RCVD_IN_MSPIKE_H5,RCVD_IN_MSPIKE_WL,SPF_HELO_PASS,SPF_PASS, T_SCC_BODY_TEXT_LINE,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Add two functions `pin_init_array_from_fn` and `init_array_from_fn` that take a function that generates initializers for `T` from usize, the added functions then return an initializer for `[T; N]` where every element is initialized by an element returned from the generator function. Suggested-by: Asahi Lina Reviewed-by: Bj=C3=B6rn Roy Baron Signed-off-by: Benno Lossin --- v1 -> v2: * fix warnings and errors in doctests * replace dropping loop with `drop_in_place` and `slice_from_raw_parts_mut` inside of `{pin_}init_array_from_fn` functions rust/kernel/init.rs | 86 +++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 86 insertions(+) diff --git a/rust/kernel/init.rs b/rust/kernel/init.rs index 460f808ebf84..fa1ebdbf5f4b 100644 --- a/rust/kernel/init.rs +++ b/rust/kernel/init.rs @@ -875,6 +875,92 @@ pub fn uninit() -> impl Init, E> = { unsafe { init_from_closure(|_| Ok(())) } } =20 +/// Initializes an array by initializing each element via the provided ini= tializer. +/// +/// # Examples +/// +/// ```rust +/// use kernel::{error::Error, init::init_array_from_fn}; +/// let array: Box<[usize; 1_000_000_000]>=3D Box::init::(init_arra= y_from_fn(|i| i)).unwrap(); +/// pr_info!("{array:?}"); +/// ``` +pub fn init_array_from_fn( + mut make_init: impl FnMut(usize) -> I, +) -> impl Init<[T; N], E> +where + I: Init, +{ + let init =3D move |slot: *mut [T; N]| { + let slot =3D slot.cast::(); + for i in 0..N { + let init =3D make_init(i); + // SAFETY: since 0 <=3D `i` < N, it is still in bounds of `[T;= N]`. + let ptr =3D unsafe { slot.add(i) }; + // SAFETY: The pointer is derived from `slot` and thus satisfi= es the `__init` + // requirements. + match unsafe { init.__init(ptr) } { + Ok(()) =3D> {} + Err(e) =3D> { + // We now free every element that has been initialized= before: + // SAFETY: The loop initialized exactly the values fro= m 0..i and since we + // return `Err` below, the caller will consider the me= mory at `slot` as + // uninitialized. + unsafe { ptr::drop_in_place(ptr::slice_from_raw_parts_= mut(slot, i)) }; + return Err(e); + } + } + } + Ok(()) + }; + // SAFETY: The initializer above initializes every element of the arra= y. On failure it drops + // any initialized elements and returns `Err`. + unsafe { init_from_closure(init) } +} + +/// Initializes an array by initializing each element via the provided ini= tializer. +/// +/// # Examples +/// +/// ```rust +/// use kernel::{sync::{Arc, Mutex}, init::pin_init_array_from_fn, new_mut= ex}; +/// let array: Arc<[Mutex; 1_000_000_000]>=3D +/// Arc::pin_init(pin_init_array_from_fn(|i| new_mutex!(i))).unwrap(); +/// pr_info!("{}", array.len()); +/// ``` +pub fn pin_init_array_from_fn( + mut make_init: impl FnMut(usize) -> I, +) -> impl PinInit<[T; N], E> +where + I: PinInit, +{ + let init =3D move |slot: *mut [T; N]| { + let slot =3D slot.cast::(); + for i in 0..N { + let init =3D make_init(i); + // SAFETY: since 0 <=3D `i` < N, it is still in bounds of `[T;= N]`. + let ptr =3D unsafe { slot.add(i) }; + // SAFETY: The pointer is derived from `slot` and thus satisfi= es the `__pinned_init` + // requirements. + match unsafe { init.__pinned_init(ptr) } { + Ok(()) =3D> {} + Err(e) =3D> { + // We now have to free every element that has been ini= tialized before, since we + // have to abide by the drop guarantee. + // SAFETY: The loop initialized exactly the values fro= m 0..i and since we + // return `Err` below, the caller will consider the me= mory at `slot` as + // uninitialized. + unsafe { ptr::drop_in_place(ptr::slice_from_raw_parts_= mut(slot, i)) }; + return Err(e); + } + } + } + Ok(()) + }; + // SAFETY: The initializer above initializes every element of the arra= y. On failure it drops + // any initialized elements and returns `Err`. + unsafe { pin_init_from_closure(init) } +} + // SAFETY: Every type can be initialized by-value. unsafe impl Init for T { unsafe fn __init(self, slot: *mut T) -> Result<(), E> { --=20 2.41.0