From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 45C0FC7EE43 for ; Fri, 9 Jun 2023 06:54:39 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229796AbjFIGyh (ORCPT ); Fri, 9 Jun 2023 02:54:37 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56688 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S238568AbjFIGyV (ORCPT ); Fri, 9 Jun 2023 02:54:21 -0400 Received: from aer-iport-8.cisco.com (aer-iport-8.cisco.com [173.38.203.70]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5E7A930F9 for ; Thu, 8 Jun 2023 23:54:18 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=cisco.com; i=@cisco.com; l=4943; q=dns/txt; s=iport; t=1686293658; x=1687503258; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=pgRmeFAK+IKfdHZ8c7lK4GY/I3z0zva/9EkiPDh+X1Q=; b=dahBm6xw9xOOZr//cG6BGKsIXM1L9tOjCelM9XI6wWo4aYLKA09EES6I uja9jptiTfMIAKZSi/aSseSCZZC1lKVbnkw0Xv94qsmAjIBy80Pn1rmJb rTikTvn2T20BjX4eJeRkDRexu4qItodbFxtauubhW/Q2Z37lNBg/sIrl+ w=; X-IronPort-AV: E=Sophos;i="6.00,228,1681171200"; d="scan'208";a="5220555" Received: from aer-iport-nat.cisco.com (HELO aer-core-5.cisco.com) ([173.38.203.22]) by aer-iport-8.cisco.com with ESMTP/TLS/DHE-RSA-SEED-SHA; 09 Jun 2023 06:31:39 +0000 Received: from archlinux-cisco.cisco.com ([10.61.198.236]) (authenticated bits=0) by aer-core-5.cisco.com (8.15.2/8.15.2) with ESMTPSA id 3596VID3055061 (version=TLSv1.2 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=NO); Fri, 9 Jun 2023 06:31:38 GMT From: Ariel Miculas To: rust-for-linux@vger.kernel.org Cc: Ariel Miculas Subject: [PATCH 09/80] rust: kernel: backport the delay module from the rust branch Date: Fri, 9 Jun 2023 09:30:07 +0300 Message-Id: <20230609063118.24852-10-amiculas@cisco.com> X-Mailer: git-send-email 2.40.1 In-Reply-To: <20230609063118.24852-1-amiculas@cisco.com> References: <20230609063118.24852-1-amiculas@cisco.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Authenticated-User: amiculas X-Outbound-SMTP-Client: 10.61.198.236, [10.61.198.236] X-Outbound-Node: aer-core-5.cisco.com Precedence: bulk List-ID: X-Mailing-List: rust-for-linux@vger.kernel.org Signed-off-by: Ariel Miculas --- rust/kernel/delay.rs | 104 +++++++++++++++++++++++++++++++++++++++++++ rust/kernel/lib.rs | 1 + 2 files changed, 105 insertions(+) create mode 100644 rust/kernel/delay.rs diff --git a/rust/kernel/delay.rs b/rust/kernel/delay.rs new file mode 100644 index 000000000000..d28d45ec2e57 --- /dev/null +++ b/rust/kernel/delay.rs @@ -0,0 +1,104 @@ +// SPDX-License-Identifier: GPL-2.0 + +//! Delay functions for operations like sleeping. +//! +//! C header: [`include/linux/delay.h`](../../../../include/linux/delay.h) + +use crate::bindings; +use core::{cmp::min, time::Duration}; + +const MILLIS_PER_SEC: u64 = 1_000; + +fn coarse_sleep_conversion(duration: Duration) -> core::ffi::c_uint { + let milli_as_nanos = Duration::MILLISECOND.subsec_nanos(); + + // Rounds the nanosecond component of `duration` up to the nearest millisecond. + let nanos_as_millis = duration.subsec_nanos().wrapping_add(milli_as_nanos - 1) / milli_as_nanos; + + // Saturates the second component of `duration` to `c_uint::MAX`. + let seconds_as_millis = min( + duration.as_secs().saturating_mul(MILLIS_PER_SEC), + u64::from(core::ffi::c_uint::MAX), + ) as core::ffi::c_uint; + + seconds_as_millis.saturating_add(nanos_as_millis) +} + +/// Sleeps safely even with waitqueue interruptions. +/// +/// This function forwards the call to the C side `msleep` function. As a result, +/// `duration` will be rounded up to the nearest millisecond if granularity less +/// than a millisecond is provided. Any [`Duration`] that exceeds +/// [`c_uint::MAX`][core::ffi::c_uint::MAX] in milliseconds is saturated. +/// +/// # Examples +/// +// Keep these in sync with `test_coarse_sleep_examples`. +/// ``` +/// # use core::time::Duration; +/// # use kernel::delay::coarse_sleep; +/// coarse_sleep(Duration::ZERO); // Equivalent to `msleep(0)`. +/// coarse_sleep(Duration::from_nanos(1)); // Equivalent to `msleep(1)`. +/// +/// coarse_sleep(Duration::from_nanos(1_000_000)); // Equivalent to `msleep(1)`. +/// coarse_sleep(Duration::from_nanos(1_000_001)); // Equivalent to `msleep(2)`. +/// coarse_sleep(Duration::from_nanos(1_999_999)); // Equivalent to `msleep(2)`. +/// +/// coarse_sleep(Duration::from_millis(1)); // Equivalent to `msleep(1)`. +/// coarse_sleep(Duration::from_millis(2)); // Equivalent to `msleep(2)`. +/// +/// coarse_sleep(Duration::from_secs(1)); // Equivalent to `msleep(1000)`. +/// coarse_sleep(Duration::new(1, 1)); // Equivalent to `msleep(1001)`. +/// coarse_sleep(Duration::new(1, 2)); // Equivalent to `msleep(1001)`. +/// ``` +pub fn coarse_sleep(duration: Duration) { + // SAFETY: msleep is safe for all values of an `unsigned int`. + unsafe { bindings::msleep(coarse_sleep_conversion(duration)) } +} + +#[cfg(test)] +mod tests { + use super::{coarse_sleep_conversion, MILLIS_PER_SEC}; + use core::time::Duration; + + #[test] + fn test_coarse_sleep_examples() { + // Keep these in sync with `coarse_sleep`'s `# Examples` section. + + assert_eq!(coarse_sleep_conversion(Duration::ZERO), 0); + assert_eq!(coarse_sleep_conversion(Duration::from_nanos(1)), 1); + + assert_eq!(coarse_sleep_conversion(Duration::from_nanos(1_000_000)), 1); + assert_eq!(coarse_sleep_conversion(Duration::from_nanos(1_000_001)), 2); + assert_eq!(coarse_sleep_conversion(Duration::from_nanos(1_999_999)), 2); + + assert_eq!(coarse_sleep_conversion(Duration::from_millis(1)), 1); + assert_eq!(coarse_sleep_conversion(Duration::from_millis(2)), 2); + + assert_eq!(coarse_sleep_conversion(Duration::from_secs(1)), 1000); + assert_eq!(coarse_sleep_conversion(Duration::new(1, 1)), 1001); + assert_eq!(coarse_sleep_conversion(Duration::new(1, 2)), 1001); + } + + #[test] + fn test_coarse_sleep_saturation() { + assert!( + coarse_sleep_conversion(Duration::new( + core::ffi::c_uint::MAX as u64 / MILLIS_PER_SEC, + 0 + )) < core::ffi::c_uint::MAX + ); + assert_eq!( + coarse_sleep_conversion(Duration::new( + core::ffi::c_uint::MAX as u64 / MILLIS_PER_SEC, + 999_999_999 + )), + core::ffi::c_uint::MAX + ); + + assert_eq!( + coarse_sleep_conversion(Duration::MAX), + core::ffi::c_uint::MAX + ); + } +} diff --git a/rust/kernel/lib.rs b/rust/kernel/lib.rs index dd9c39071391..9dc9124a5bd7 100644 --- a/rust/kernel/lib.rs +++ b/rust/kernel/lib.rs @@ -35,6 +35,7 @@ mod allocator; mod build_assert; pub mod cred; +pub mod delay; pub mod error; pub mod file; pub mod fs; -- 2.40.1