From nobody Fri Dec 19 20:52:36 2025 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) (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 7111D25229C for ; Tue, 15 Apr 2025 19:50:44 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.133.124 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1744746646; cv=none; b=qaTw4dEd5jnXkfUQhqFn8tijD/DXq2wwZs51fP0NL4RirG8piG3hw6oKzyNjcKAp08OneuUuaJfM8LmhH8NrO3BrTf93UOMAHiM7UHS/1RS77H+eUnQl8KF1FW2yh9VYe78FhYnORZwmCXxAiegu45kRNvEaqNC92uc5vWAyJLo= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1744746646; c=relaxed/simple; bh=BbdWQ0YbkE2htZOld0PCHaFrACpyTKErMgewUedBg3U=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=Iz2eT/YNFsGmm1F0ccb+/RtENyTVOIL4E2+UdQgJWayYiSPqDN89kubDfP4d5IPUAGz7nCh2SZ6sWThD4UKhZqgIfet1IZI3Zvvu/bTirun0vv23WkBxgLn5ZjA9M/aSYkCt5USGLK5TM2urC95EqbqA0w3Q+iOYmC0MhVJ05aM= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=gNG4ImVw; arc=none smtp.client-ip=170.10.133.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="gNG4ImVw" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1744746643; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=9caeaEvOrQMjWI6dFVaM+47fZcpqeIYiQQAHDs+mWKA=; b=gNG4ImVwQbOzxpXLWNS+82DcrsR5c/PP9g2Obd6Fk7/A++9mPDHLisyLoRjToUDGrxCsWD SX9Zu/DDwe8FJ/uDzLCUq55j80CmSuKag6DkJ647o6gP3VaUxPqwQ8llG4SK5wjUVrfbd+ B+hNU7UemMevgOH00R0fcBZmW+2/29Y= Received: from mx-prod-mc-08.mail-002.prod.us-west-2.aws.redhat.com (ec2-35-165-154-97.us-west-2.compute.amazonaws.com [35.165.154.97]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-446-K2_kQgv8NMaDj3e4fNMfLw-1; Tue, 15 Apr 2025 15:50:39 -0400 X-MC-Unique: K2_kQgv8NMaDj3e4fNMfLw-1 X-Mimecast-MFC-AGG-ID: K2_kQgv8NMaDj3e4fNMfLw_1744746637 Received: from mx-prod-int-04.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-04.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.40]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-08.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 0C3D518007E1; Tue, 15 Apr 2025 19:50:37 +0000 (UTC) Received: from chopper.redhat.com (unknown [10.22.88.101]) by mx-prod-int-04.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id 924A519560AD; Tue, 15 Apr 2025 19:50:32 +0000 (UTC) From: Lyude Paul To: rust-for-linux@vger.kernel.org, Andreas Hindborg , linux-kernel@vger.kernel.org Cc: Boqun Feng , FUJITA Tomonori , Frederic Weisbecker , Thomas Gleixner , Anna-Maria Behnsen , John Stultz , Stephen Boyd , Miguel Ojeda , Alex Gaynor , Gary Guo , =?UTF-8?q?Bj=C3=B6rn=20Roy=20Baron?= , Benno Lossin , Alice Ryhl , Trevor Gross , Danilo Krummrich Subject: [PATCH v2 2/8] rust: hrtimer: Add HrTimer::raw_forward() and forward() Date: Tue, 15 Apr 2025 15:48:23 -0400 Message-ID: <20250415195020.413478-3-lyude@redhat.com> In-Reply-To: <20250415195020.413478-1-lyude@redhat.com> References: <20250415195020.413478-1-lyude@redhat.com> Precedence: bulk X-Mailing-List: linux-kernel@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-Scanned-By: MIMEDefang 3.0 on 10.30.177.40 Within the hrtimer API there are quite a number of functions that can only be safely called from one of two contexts: * When we have exclusive access to the hrtimer and the timer is not active. * When we're within the hrtimer's callback context as it is being executed. This commit adds bindings for hrtimer_forward() for the first such context, along with HrTimer::raw_forward() for later use in implementing the hrtimer_forward() in the latter context. Since we can only retrieve a &mut reference to an HrTimer in contexts where it is not possible for the timer to be accessed by others or currently executing (e.g. a UniqueArc), a &mut is actually enough of a guarantee to safely fulfill the C API requirements here. Signed-off-by: Lyude Paul --- rust/kernel/time/hrtimer.rs | 36 +++++++++++++++++++++++++++++++++++- 1 file changed, 35 insertions(+), 1 deletion(-) diff --git a/rust/kernel/time/hrtimer.rs b/rust/kernel/time/hrtimer.rs index bfe0e25f5abd0..aadae8666f7ea 100644 --- a/rust/kernel/time/hrtimer.rs +++ b/rust/kernel/time/hrtimer.rs @@ -68,7 +68,11 @@ //! `start` operation. =20 use super::ClockId; -use crate::{prelude::*, time::Instant, types::Opaque}; +use crate::{ + prelude::*, + time::{Delta, Instant}, + types::Opaque, +}; use core::marker::PhantomData; use pin_init::PinInit; =20 @@ -164,6 +168,36 @@ pub(crate) unsafe fn raw_cancel(this: *const Self) -> = bool { // handled on the C side. unsafe { bindings::hrtimer_cancel(c_timer_ptr) !=3D 0 } } + + /// Forward the timer expiry for a given timer pointer. + /// + /// # Safety + /// + /// `self_ptr` must point to a valid `Self`. + unsafe fn raw_forward(self_ptr: *mut Self, now: Instant, interval: Del= ta) -> u64 { + // SAFETY: + // * The C API requirements for this function are fulfilled by our= safety contract. + // * `self_ptr` is guaranteed to point to a valid `Self` via our s= afety contract + unsafe { + bindings::hrtimer_forward(Self::raw_get(self_ptr), now.as_nano= s(), interval.as_nanos()) + } + } + + /// Forward the timer expiry so it expires at `duration` after `now`. + /// + /// This is mainly useful for timer types that can start off providing= a mutable reference (e.g. + /// `Pin>`) before the timer is started. + /// + /// Note that this does not requeue the timer, it simply updates its e= xpiry value. It returns + /// the number of overruns that have occurred as a result of the expir= y change. + pub fn forward(&mut self, now: Instant, duration: Delta) -> u64 { + // SAFETY: + // - Self is a mutable reference and thus always points to a valid= `HrTimer` + // - The only way we could hold a mutable reference to a `HrTimer<= T>` is if we have + // exclusive access to it, which means the timer is either idle = or we're within the + // timer callback context - fulfilling the requirements of the C= API. + unsafe { Self::raw_forward(self, now, duration) } + } } =20 /// Implemented by pointer types that point to structs that contain a [`Hr= Timer`]. --=20 2.48.1