From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 E6DE1246BCD for ; Fri, 17 Jul 2026 20:31:51 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784320312; cv=none; b=HstAw/defSHuF2uF4QnTZOgz0jWrZVFNwfxC7CVBQfaepBqSn7lohyzayxeWyulwQHYl7g6DidJnPgFHy5yelgAEO3lFEQnQE3HTl51rRLjkaSA7BS2YBFEEtvj1OH6nFzKCEBodgY6D8IF7sYyhqeX5aTT+O2Xwz7cRv/tYDCA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784320312; c=relaxed/simple; bh=A6Wo54h7aA/q5dNpBpmr8zM1B2DQhlJE3d4IGWU43os=; h=From:To:Cc:Subject:In-Reply-To:References:Date:Message-ID: MIME-Version:Content-Type; b=fDhv6iCkO078723kzMrLTq0R5NaGIQMN/7GqOQQzw/dkpbJAmuv+ELkrJqZ93K00MfqqexgnMu/OgHdYDHegeW7a3b5M4kDubOoqJp1nVv7Otc/JlEotxFUK2U/5MG3c2WMpfc2c61+XVMFQ2NIH348Wg1pmC6twjpXIhvU0Z04= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=nPfLpCPz; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="nPfLpCPz" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9F62E1F00A3A; Fri, 17 Jul 2026 20:31:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1784320311; bh=A6Wo54h7aA/q5dNpBpmr8zM1B2DQhlJE3d4IGWU43os=; h=From:To:Cc:Subject:In-Reply-To:References:Date; b=nPfLpCPz0KMWhgV+0ddgwspFN4OOLQBEXY/+19uMqOQ4tlwzU1h9MCIC/orFbA7zJ m4A0tVUdLlDa82Sv+5KkzcSUuJOYdjpE80Ox24iadXYOdtJ8XNX4ImdwpXUqkCv4ka htuOb1fxJIsIsRWs+xo4AzjRZTL/1H8cAdQTwaUaDU/8/3JUMwQpjzwgWdIbpIAy+Y FXRaovkgUXR9CBmA3H7Y9CXQqgeZ3qx2u4E5GxFgW1uSUL85xM5AohPt5OhHkRr/cn iPNdEfOtMKZEwBCHPZ1+0Redw/NjidLAIEraTUacsF7LkgxxhMM811MadZ/dIfP5s0 ZIl7X/+mYaAfw== From: Andreas Hindborg To: FUJITA Tomonori , ojeda@kernel.org Cc: acourbot@nvidia.com, aliceryhl@google.com, anna-maria@linutronix.de, bjorn3_gh@protonmail.com, boqun@kernel.org, dakr@kernel.org, daniel.almeida@collabora.com, frederic@kernel.org, gary@garyguo.net, jstultz@google.com, lossin@kernel.org, lyude@redhat.com, sboyd@kernel.org, tamird@kernel.org, tglx@kernel.org, tmgross@umich.edu, work@onurozkan.dev, rust-for-linux@vger.kernel.org, FUJITA Tomonori Subject: Re: [PATCH v1] rust: time: fix as_micros_ceil() to round correctly for negative Delta In-Reply-To: <20260713225235.3243480-1-tomo@flapping.org> References: <20260713225235.3243480-1-tomo@flapping.org> Date: Fri, 17 Jul 2026 22:26:33 +0200 Message-ID: <877bmtgy6e.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 "FUJITA Tomonori" writes: > From: FUJITA Tomonori > > The ceiling-division idiom `(n + d - 1) / d` only produces the > correct result when `n` is non-negative. > > For example, if n = -1000 (exactly -1us), the old code computed (-1000 > + 999) / 1000 == 0 instead of -1. > > For negative n, truncating division already rounds towards positive > infinity, so no bias is needed in that case. > > Fixes: fae0cdc12340 ("rust: time: Introduce Delta type") > Signed-off-by: FUJITA Tomonori Acked-by: Andreas Hindborg @Miguel, can you take this with rust fixes? Best regards, Andreas Hindborg