From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mout02.posteo.de (mout02.posteo.de [185.67.36.66]) (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 B797A2ED860 for ; Fri, 10 Oct 2025 21:14:15 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=185.67.36.66 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1760130858; cv=none; b=XqL3iYGnU97byX1ofd/YgcPssYrlfsoDIXFWkowc2675LHGfqNZnIcq/fx7+MQfujWwefwWAEq4MbnSD/9h79zy//MZ0ZqKK64LKZg8JdnG/RE66N2e6saPVsmoc2jPCalBVtxahXQHyZX9Gzdog95q/6GKkbO47EE35Er0otbs= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1760130858; c=relaxed/simple; bh=tBXWf+kYSdFQSa6c+ZkdKlqIQPsi02XHseYQ0sNDpk4=; h=Message-ID:Subject:From:To:Cc:Date:In-Reply-To:References: Content-Type:MIME-Version; b=jfALKhx0MBIWRVejyGLyKUqFIulgwvkRwzy5zS3BXnwEZRCoRv6tKRVaG+W07IxteWKtIzop4N2yJ7F4OYJbcUmqE2xA5GaxRc/apqEjIuo6WAnjkAdcw/jWjDlNjJ2e6yArNow8ikPDm9HVqN38c2FOTwmx4qjX6qIRGNV54YA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=posteo.de; spf=pass smtp.mailfrom=posteo.de; dkim=pass (2048-bit key) header.d=posteo.de header.i=@posteo.de header.b=gA8RxDlW; arc=none smtp.client-ip=185.67.36.66 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=posteo.de Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=posteo.de Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=posteo.de header.i=@posteo.de header.b="gA8RxDlW" Received: from submission (posteo.de [185.67.36.169]) by mout02.posteo.de (Postfix) with ESMTPS id A5F04240101 for ; Fri, 10 Oct 2025 23:14:08 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=posteo.de; s=2017; t=1760130848; bh=tBXWf+kYSdFQSa6c+ZkdKlqIQPsi02XHseYQ0sNDpk4=; h=Message-ID:Subject:From:To:Cc:Date:Content-Type: Content-Transfer-Encoding:MIME-Version:Autocrypt:OpenPGP:From; b=gA8RxDlWhko5kmY6cjAUyfVJTF/YvN77uC/nJYnKmHXUaRcGVcduaYp3C6K2TJAM0 T0Xa3l1HCEeDUguCkqAFAU5VhWnep1yzRmpreAmu8rEXXYxcyei8QMwmjo85G2sEn1 aXOZRl1sKs6dOjnG5A4sCFQdbAovidsFvxdx6Uaw2rbnckM8SKSNFDPpxGlm4O8i8k nmNDikGfQ6xepQ6BknRQO+KBfNIF1e2ESeq557/LW17VbEZ5rYZMNOE9YGgaOYfwyf E8A6wPCF2vLjlJOuQP1vKHukJQG/zk0aixGz1gsR0DPItazYqyLYKbdS2am+ijROsn vhCRacYuTDmYw== Received: from customer (localhost [127.0.0.1]) by submission (posteo.de) with ESMTPSA id 4cjzy63dCcz9rxW; Fri, 10 Oct 2025 23:14:06 +0200 (CEST) Message-ID: Subject: Re: [PATCH v2 1/2] rust: add basic Pin> abstractions From: Markus Probst To: Alice Ryhl Cc: Danilo Krummrich , Miguel Ojeda , Alex Gaynor , Lee Jones , Pavel Machek , Lorenzo Stoakes , Vlastimil Babka , "Liam R. Howlett" , Uladzislau Rezki , Boqun Feng , Gary Guo , bjorn3_gh@protonmail.com, Benno Lossin , Andreas Hindborg , Trevor Gross , rust-for-linux@vger.kernel.org, linux-kernel@vger.kernel.org, linux-leds@vger.kernel.org Date: Fri, 10 Oct 2025 21:14:07 +0000 In-Reply-To: References: <20251009181203.248471-1-markus.probst@posteo.de> <20251009181203.248471-2-markus.probst@posteo.de> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Precedence: bulk X-Mailing-List: linux-leds@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Autocrypt: addr=markus.probst@posteo.de; prefer-encrypt=mutual; keydata=xsFNBGiDvXgBEADAXUceKafpl46S35UmDh2wRvvx+UfZbcTjeQOlSwKP7YVJ4JOZrVs93qReNLkO WguIqPBxR9blQ4nyYrqSCV+MMw/3ifyXIm6Pw2YRUDg+WTEOjTixRCoWDgUj1nOsvJ9tVAm76Ww+ /pAnepVRafMID0rqEfD9oGv1YrfpeFJhyE2zUw3SyyNLIKWD6QeLRhKQRbSnsXhGLFBXCqt9k5JA RhgQof9zvztcCVlT5KVvuyfC4H+HzeGmu9201BVyihJwKdcKPq+n/aY5FUVxNTgtI9f8wIbmfAja oT1pjXSp+dszakA98fhONM98pOq723o/1ZGMZukyXFfsDGtA3BB79HoopHKujLGWAGskzClwTjRQ xBqxh/U/lL1pc+0xPWikTNCmtziCOvv0KA0arDOMQlyFvImzX6oGVgE4ksKQYbMZ3Ikw6L1Rv1J+ FvN0aNwOKgL2ztBRYscUGcQvA0Zo1fGCAn/BLEJvQYShWKeKqjyncVGoXFsz2AcuFKe1pwETSsN6 OZncjy32e4ktgs07cWBfx0v62b8md36jau+B6RVnnodaA8++oXl3FRwiEW8XfXWIjy4umIv93tb8 8ekYsfOfWkTSewZYXGoqe4RtK80ulMHb/dh2FZQIFyRdN4HOmB4FYO5sEYFr9YjHLmDkrUgNodJC XCeMe4BO4iaxUQARAQABzRdtYXJrdXMucHJvYnN0QHBvc3Rlby5kZcLBkQQTAQgAOxYhBIJ0GMT0 rFjncjDEczR2H/jnrUPSBQJog714AhsDBQsJCAcCAiICBhUKCQgLAgQWAgMBAh4HAheAAAoJEDR2 H/jnrUPSgdkQAISaTk2D345ehXEkn5z2yUEjaVjHIE7ziqRaOgn/QanCgeTUinIv6L6QXUFvvIfH 1OLPwQ1hfvEg9NnNLyFezWSy6jvoVBTIPqicD/r3FkithnQ1IDkdSjrarPMxJkvuh3l7XZHo49GV HQ8i5zh5w4YISrcEtE99lJisvni2Jqx7we5tey9voQFDyM8jxlSWv3pmoUTCtBkX/eKHJXosgsuS B4TGDCVPOjla/emI5c9MhMG7O4WEEmoSdPbmraPw66YZD6uLyhV4DPHbiDWRzXWnClHSyjB9rky9 lausFxogvu4l9H+KDsXIadNDWdLdu1/enS/wDd9zh5S78rY2jeXaG4mnf4seEKamZ7KQ6FIHrcyP ezdDzssPQcTQcGRMQzCn6wP3tlGk7rsfmyHMlFqdRoNNv+ZER/OkmZFPW655zRfbMi0vtrqK2Awm 9ggobb1oktfd9PPNXMUY+DNVlgR2G7jLnenSoQausLUm0pHoNE8TWFv851Y6SOYnvn488sP1Tki5 F3rKwclawQFHUXTCQw+QSh9ay8xgnNZfH+u9NY7w3gPoeKBOAFcBc2BtzcgekeWS8qgEmm2/oNFV G0ivPQbRx8FjRKbuF7g3YhgNZZ0ac8FneuUtJ2PkSIFTZhaAiC0utvxk0ndmWFiW4acEkMZGrLaM L2zWNjrqwsD2zsFNBGiDvXgBEADCXQy1n7wjRxG12DOVADawjghKcG+5LtEf31WftHKLFbp/HArj BhkT6mj+CCI1ClqY+FYU5CK/s0ScMfLxRGLZ0Ktzawb78vOgBVFT3yB1yWBTewsAXdqNqRooaUNo 8cG/NNJLjhccH/7PO/FWX5qftOVUJ/AIsAhKQJ18Tc8Ik73v427EDxuKb9mTAnYQFA3Ev3hAiVbO 6Rv39amVOfJ8sqwiSUGidj2Fctg2aB5JbeMln0KCUbTD1LhEFepeKypfofAXQbGwaCjAhmkWy/q3 IT1mUrPxOngbxdRoOx1tGUC0HCMUW1sFaJgQPMmDcR0JGPOpgsKnitsSnN7ShcCr1buel7vLnUMD +TAZ5opdoF6HjAvAnBQaijtK6minkrM0seNXnCg0KkV8xhMNa6zCs1rq4GgjNLJue2EmuyHooHA4 7JMoLVHcxVeuNTp6K2+XRx0Pk4e2Lj8IVy9yEYyrywEOC5XRW37KJjsiOAsumi1rkvM7QREWgUDe Xs0+RpxI3QrrANh71fLMRo7LKRF3Gvw13NVCCC9ea20P4PwhgWKStkwO2NO+YJsAoS1QycMi/vKu 0EHhknYXamaSV50oZzHKmX56vEeJHTcngrM8R1SwJCYopCx9gkz90bTVYlitJa5hloWTYeMD7FNj Y6jfVSzgM/K4gMgUNDW/PPGeMwARAQABwsF2BBgBCAAgFiEEgnQYxPSsWOdyMMRzNHYf+OetQ9IF AmiDvXgCGwwACgkQNHYf+OetQ9LHDBAAhk+ab8+WrbS/b1/gYW3q1KDiXU719nCtfkUVXKidW5Ec Idlr5HGt8ilLoxSWT2Zi368iHCXS0WenGgPwlv8ifvB7TOZiiTDZROZkXjEBmU4nYjJ7GymawpWv oQwjMsPuq6ysbzWtOZ7eILx7cI0FjQeJ/Q2baRJub0uAZNwBOxCkAS6lpk5Fntd2u8CWmDQo4SYp xeuQ+pwkp0yEP30RhN2BO2DXiBEGSZSYh+ioGbCHQPIV3iVj0h6lcCPOqopZqyeCfigeacBI0nvN jHWz/spzF3+4OS+3RJvoHtAQmProxyGib8iVsTxgZO3UUi4TSODeEt0i0kHSPY4sCciOyXfAyYoD DFqhRjOEwBBxhr+scU4C1T2AflozvDwq3VSONjrKJUkhd8+WsdXxMdPFgBQuiKKwUy11mz6KQfcR wmDehF3UaUoxa+YIhWPbKmycxuX/D8SvnqavzAeAL1OcRbEI/HsoroVlEFbBRNBZLJUlnTPs8ZcU 4+8rq5YX1GUrJL3jf6SAfSgO7UdkEET3PdcKFYtS+ruV1Cp5V0q4kCfI5jk25iiz8grM2wOzVSsc l1mEkhiEPH87HP0whhb544iioSnumd3HJKL7dzhRegsMizatupp8D65A2JziW0WKopa1iw9fti3A aBeNN4ijKZchBXHPgVx+YtWRHfcm4l8= OpenPGP: url=https://posteo.de/keys/markus.probst@posteo.de.asc; preference=encrypt I might be wrong here, but as far as I know, it is not possible to get a `Pin<&mut Vec>` from a `&mut Pin>`, only a `&mut Pin<&mut [T, A]>` which is not usable by any of these methods. Thanks - Markus Probst On Fri, 2025-10-10 at 11:33 +0000, Alice Ryhl wrote: > On Thu, Oct 09, 2025 at 06:12:33PM +0000, Markus Probst wrote: > > Implement core Pin> abstractions, including > > =C2=A0* `Vec::pin` and `Vec::into_pin` for constructing a `Pin > A>>`. > > =C2=A0=C2=A0 If T does not implement `Unpin`, its values will never be = moved. > > =C2=A0* an extension for `Pin>` allowing PinInit to be > > initialied on a > > =C2=A0=C2=A0 Pin, as well as truncating and popping values from th= e Vec > >=20 > > Signed-off-by: Markus Probst > > --- > > =C2=A0rust/kernel/alloc.rs=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 |=C2=A0 1 + > > =C2=A0rust/kernel/alloc/kvec.rs | 86 > > +++++++++++++++++++++++++++++++++++++++ > > =C2=A0rust/kernel/prelude.rs=C2=A0=C2=A0=C2=A0 |=C2=A0 2 +- > > =C2=A03 files changed, 88 insertions(+), 1 deletion(-) > >=20 > > diff --git a/rust/kernel/alloc.rs b/rust/kernel/alloc.rs > > index a2c49e5494d3..9c129eaf0625 100644 > > --- a/rust/kernel/alloc.rs > > +++ b/rust/kernel/alloc.rs > > @@ -24,6 +24,7 @@ > > =C2=A0pub use self::kvec::KVec; > > =C2=A0pub use self::kvec::VVec; > > =C2=A0pub use self::kvec::Vec; > > +pub use self::kvec::PinnedVecExt; > > =C2=A0 > > =C2=A0/// Indicates an allocation error. > > =C2=A0#[derive(Copy, Clone, PartialEq, Eq, Debug)] > > diff --git a/rust/kernel/alloc/kvec.rs b/rust/kernel/alloc/kvec.rs > > index 3c72e0bdddb8..d5582a7f17e9 100644 > > --- a/rust/kernel/alloc/kvec.rs > > +++ b/rust/kernel/alloc/kvec.rs > > @@ -16,11 +16,13 @@ > > =C2=A0=C2=A0=C2=A0=C2=A0 ops::DerefMut, > > =C2=A0=C2=A0=C2=A0=C2=A0 ops::Index, > > =C2=A0=C2=A0=C2=A0=C2=A0 ops::IndexMut, > > +=C2=A0=C2=A0=C2=A0 pin::Pin, > > =C2=A0=C2=A0=C2=A0=C2=A0 ptr, > > =C2=A0=C2=A0=C2=A0=C2=A0 ptr::NonNull, > > =C2=A0=C2=A0=C2=A0=C2=A0 slice, > > =C2=A0=C2=A0=C2=A0=C2=A0 slice::SliceIndex, > > =C2=A0}; > > +use pin_init::PinInit; > > =C2=A0 > > =C2=A0mod errors; > > =C2=A0pub use self::errors::{InsertError, PushError, RemoveError}; > > @@ -109,6 +111,21 @@ pub struct Vec { > > =C2=A0=C2=A0=C2=A0=C2=A0 _p: PhantomData, > > =C2=A0} > > =C2=A0 > > +/// Extension for Pin> > > +pub trait PinnedVecExt { > > +=C2=A0=C2=A0=C2=A0 /// Pin-initializes P and appends it to the back of= the > > [`Vec`] instance without reallocating. > > +=C2=A0=C2=A0=C2=A0 fn push_pin_init>, P: PinInit<= T, E>>(&mut > > self, init: P) -> Result<(), E>; > > + > > +=C2=A0=C2=A0=C2=A0 /// Shortens the vector, setting the length to `len= ` and drops > > the removed values. > > +=C2=A0=C2=A0=C2=A0 /// If `len` is greater than or equal to the curren= t length, > > this does nothing. > > +=C2=A0=C2=A0=C2=A0 /// > > +=C2=A0=C2=A0=C2=A0 /// This has no effect on the capacity and will not= allocate. > > +=C2=A0=C2=A0=C2=A0 fn truncate(&mut self, len: usize); > > + > > +=C2=A0=C2=A0=C2=A0 /// Removes the last element from a vector and drop= s it > > returning true, or false if it is empty. > > +=C2=A0=C2=A0=C2=A0 fn pop(&mut self) -> bool; > > +} >=20 > Please no extension traits just for this. Just provide `self: > Pin<&mut Self>` > methods on Vec. >=20 > Alice