From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 8EC6612BF02; Wed, 20 Nov 2024 15:51:59 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1732117919; cv=none; b=ui7iJBrmfy2pBZzwsVjOkPtgP2xJsD0TQ4Fu/loKTTXb5shsIAmW47hKY+9T8mraRu7tWfRs0RmLVPDG5fMe01AoGGsjCzkZk7Xi9gnhWO6Zvqn529waCyQmDCfHKChHDrulUqvZKG/QrTFgaUO9lYZH9cCycXgY5Zay1RJLezQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1732117919; c=relaxed/simple; bh=8IVlxGS65y/Z3LoG7hMZVm0036HIRMtQCt9WMX5LvSs=; h=From:To:Cc:Subject:In-Reply-To:References:Date:Message-ID: MIME-Version:Content-Type; b=gFBFIUcv6juaqshczTb9FQquEHgiZA2q/ttbrzGttK2b0N8DkWdLfa1YNb6PJnaHVEsPIgj3mv8e+J1kHYpNnrB01FNc4Nd+yzI9dL/LLtHeyWWpagcVjKRwLpGCzvIwsW0C2xoAcrd02p6p7yC3YftkCkDd/erzumJERBR4WUg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=WN9X5vHA; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="WN9X5vHA" Received: by smtp.kernel.org (Postfix) with ESMTPSA id D7B8EC4CECD; Wed, 20 Nov 2024 15:51:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1732117919; bh=8IVlxGS65y/Z3LoG7hMZVm0036HIRMtQCt9WMX5LvSs=; h=From:To:Cc:Subject:In-Reply-To:References:Date:From; b=WN9X5vHAn8EZDfk/XToTYw0qs7/N4R/AVvvRgNYbMvSfSK138ceU6Ooo6mfEEoo4Q J0tkUZxSD47qNUS8o1EiIy4yNv/7Yi2ZYvTtS3cUhCKW320koNEwfbgmD55S+vWZUo +lAv5dfK/mv5CNCPCMGYIUWWk6blMQ0/+YNXiu/ZaeAjjCHI4emtzi6+03ff7gc0Xi kTBzH+Pv2WRi+H6SeWJeHPJprq69z0l6lFrbmQ9iWTAaoODJq6I+o0MAOFxYLPIHWD +NHs2cTPRRoBKqhWNZCMcO9PIquZQYYNncBIA/+iP089JSVmCWLE9DV78JBS3ccjh5 JKyfL/8nmVicA== From: Andreas Hindborg To: "Lyude Paul" Cc: "Miguel Ojeda" , "Anna-Maria Behnsen" , "Frederic Weisbecker" , "Thomas Gleixner" , "Alex Gaynor" , "Boqun Feng" , "Gary Guo" , =?utf-8?Q?Bj=C3=B6rn?= Roy Baron , "Benno Lossin" , "Alice Ryhl" , "Trevor Gross" , , Subject: Re: [PATCH v3 11/13] rust: hrtimer: add `TimerMode` In-Reply-To: (Lyude Paul's message of "Wed, 13 Nov 2024 18:37:31 -0500") References: <20241017-hrtimer-v3-v6-12-rc2-v3-0-59a75cbb44da@kernel.org> <20241017-hrtimer-v3-v6-12-rc2-v3-11-59a75cbb44da@kernel.org> Date: Wed, 20 Nov 2024 16:51:44 +0100 Message-ID: <87r0753nu7.fsf@kernel.org> 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 "Lyude Paul" writes: > On Thu, 2024-10-17 at 15:04 +0200, Andreas Hindborg wrote: >> Allow selection of timer mode by passing a `TimerMode` variant to >> `Timer::new`. >> >> Signed-off-by: Andreas Hindborg >> --- >> rust/kernel/hrtimer.rs | 88 +++++++++++++++++++++++++++++++++++++++++++= ++++--- >> 1 file changed, 84 insertions(+), 4 deletions(-) >> >> diff --git a/rust/kernel/hrtimer.rs b/rust/kernel/hrtimer.rs >> index 2c1573e19576de93afc959d71e94173e2c1ed715..1674d1dcba39cc7ab82e1f18= 9002afa365ee9341 100644 >> --- a/rust/kernel/hrtimer.rs >> +++ b/rust/kernel/hrtimer.rs >> @@ -38,12 +38,13 @@ >> /// # Invariants >> /// >> /// * `self.timer` is initialized by `bindings::hrtimer_init`. >> -#[repr(transparent)] >> #[pin_data] >> #[repr(C)] >> pub struct Timer { >> #[pin] >> timer: Opaque, >> + // This field goes away when `bindings::hrtimer_setup` is added. >> + mode: TimerMode, >> _t: PhantomData, >> } >> >> @@ -56,7 +57,7 @@ unsafe impl Sync for Timer {} >> >> impl Timer { >> /// Return an initializer for a new timer instance. >> - pub fn new() -> impl PinInit >> + pub fn new(mode: TimerMode) -> impl PinInit >> where >> T: TimerCallback, >> { >> @@ -70,7 +71,7 @@ pub fn new() -> impl PinInit >> bindings::hrtimer_init( >> place, >> bindings::CLOCK_MONOTONIC as i32, >> - bindings::hrtimer_mode_HRTIMER_MODE_REL, >> + mode.into(), >> ); >> } >> >> @@ -83,6 +84,7 @@ pub fn new() -> impl PinInit >> // exclusive access. >> unsafe { core::ptr::write(function, Some(T::CallbackTar= get::run)) }; >> }), >> + mode: mode, >> _t: PhantomData, >> }) >> } >> @@ -330,7 +332,7 @@ unsafe fn start(self_ptr: *const Self, expires: Ktim= e) { >> Self::c_timer_ptr(self_ptr).cast_mut(), >> expires.to_ns(), >> 0, >> - bindings::hrtimer_mode_HRTIMER_MODE_REL, >> + (*Self::raw_get_timer(self_ptr)).mode.into(), >> ); >> } >> } >> @@ -362,6 +364,84 @@ fn from(value: TimerRestart) -> Self { >> } >> } >> >> +/// Operational mode of [`Timer`]. >> +#[derive(Clone, Copy)] >> +pub enum TimerMode { >> + /// Timer expires at the given expiration time. >> + Absolute, >> + /// Timer expires after the given expiration time interpreted as a = duration from now. >> + Relative, >> + /// Timer does not move between CPU cores. >> + Pinned, >> + /// Timer handler is executed in soft irq context. >> + Soft, >> + /// Timer handler is executed in hard irq context. >> + Hard, >> + /// Timer expires at the given expiration time. >> + /// Timer does not move between CPU cores. >> + AbsolutePinned, >> + /// Timer expires after the given expiration time interpreted as a = duration from now. >> + /// Timer does not move between CPU cores. >> + RelativePinned, >> + /// Timer expires at the given expiration time. >> + /// Timer handler is executed in soft irq context. >> + AbsoluteSoft, >> + /// Timer expires after the given expiration time interpreted as a = duration from now. >> + /// Timer handler is executed in soft irq context. >> + RelativeSoft, >> + /// Timer expires at the given expiration time. >> + /// Timer does not move between CPU cores. >> + /// Timer handler is executed in soft irq context. >> + AbsolutePinnedSoft, >> + /// Timer expires after the given expiration time interpreted as a = duration from now. >> + /// Timer does not move between CPU cores. >> + /// Timer handler is executed in soft irq context. >> + RelativePinnedSoft, >> + /// Timer expires at the given expiration time. >> + /// Timer handler is executed in hard irq context. >> + AbsoluteHard, >> + /// Timer expires after the given expiration time interpreted as a = duration from now. >> + /// Timer handler is executed in hard irq context. >> + RelativeHard, >> + /// Timer expires at the given expiration time. >> + /// Timer does not move between CPU cores. >> + /// Timer handler is executed in hard irq context. >> + AbsolutePinnedHard, >> + /// Timer expires after the given expiration time interpreted as a = duration from now. >> + /// Timer does not move between CPU cores. >> + /// Timer handler is executed in hard irq context. >> + RelativePinnedHard, >> +} >> + >> +impl From for bindings::hrtimer_mode { >> + fn from(value: TimerMode) -> Self { >> + use bindings::*; >> + match value { >> + TimerMode::Absolute =3D> hrtimer_mode_HRTIMER_MODE_ABS, >> + TimerMode::Relative =3D> hrtimer_mode_HRTIMER_MODE_REL, >> + TimerMode::Pinned =3D> hrtimer_mode_HRTIMER_MODE_PINNED, >> + TimerMode::Soft =3D> hrtimer_mode_HRTIMER_MODE_SOFT, >> + TimerMode::Hard =3D> hrtimer_mode_HRTIMER_MODE_HARD, >> + TimerMode::AbsolutePinned =3D> hrtimer_mode_HRTIMER_MODE_AB= S_PINNED, >> + TimerMode::RelativePinned =3D> hrtimer_mode_HRTIMER_MODE_RE= L_PINNED, >> + TimerMode::AbsoluteSoft =3D> hrtimer_mode_HRTIMER_MODE_ABS_= SOFT, >> + TimerMode::RelativeSoft =3D> hrtimer_mode_HRTIMER_MODE_REL_= SOFT, >> + TimerMode::AbsolutePinnedSoft =3D> hrtimer_mode_HRTIMER_MOD= E_ABS_PINNED_SOFT, >> + TimerMode::RelativePinnedSoft =3D> hrtimer_mode_HRTIMER_MOD= E_REL_PINNED_SOFT, >> + TimerMode::AbsoluteHard =3D> hrtimer_mode_HRTIMER_MODE_ABS_= HARD, >> + TimerMode::RelativeHard =3D> hrtimer_mode_HRTIMER_MODE_REL_= HARD, >> + TimerMode::AbsolutePinnedHard =3D> hrtimer_mode_HRTIMER_MOD= E_ABS_PINNED_HARD, >> + TimerMode::RelativePinnedHard =3D> hrtimer_mode_HRTIMER_MOD= E_REL_PINNED_HARD, >> + } >> + } >> +} > > Are we sure we actually need to explicitly convert it like this? You shou= ld be > able to use #[repr(=E2=80=A6)] to indicate that the enum is the same type= as the > actual C constant, and then we can just assign the value of each C consta= nt as > the discriminant for each enum value in TimerMode. > Some combinations of modes are illegal. With this approach, it is not possible to name the illegal combinations. Interesting discussion is happening on Zulip regarding a possible solution for enums like this [1]. Best regards, Andreas Hindborg [1] https://rust-for-linux.zulipchat.com/#narrow/channel/291565-Help/topic/= Best.20way.20to.20handle.20enum.2Fflags.20situation