From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-10628.protonmail.ch (mail-10628.protonmail.ch [79.135.106.28]) (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 7F515D2FB; Wed, 19 Mar 2025 00:50:41 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=79.135.106.28 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1742345444; cv=none; b=FUgc2DbTKEUOzIB/RorWo+umyPboPibm56JyaYkKdACZiP0jBXmoWcB4Ks90I0p086dJPA23d9CvHg+cGCknRlFfHwVHIcElNpd9cAIrd3pFvaHLTnedeeyIpdbI0mBDFrgknmsHeXrdoa4fgpf3XdAAk4XbTEMqb5NGMuaZgK0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1742345444; c=relaxed/simple; bh=NeEU7i74gwTAa1WttGzCW7vliZqsygMpqhOWUejssws=; h=Date:To:From:Cc:Subject:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=tddNr9vtpyNDCl8baYnKEfFEMP/9EalkP33v5fMdnFw2SUfc9i+XKCtgw52AXh5WFmFYhm10/HC2CKlPDxA2zdEqfJ8CRfbcKhyURiLniE+MpPRVOduIgmNG64yyLkTo9ByqVhMxXbTf8dSNGD0r3uSXG6XISfDOoqcr5WkoDaM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=proton.me; spf=pass smtp.mailfrom=proton.me; dkim=pass (2048-bit key) header.d=proton.me header.i=@proton.me header.b=OuvlnTKG; arc=none smtp.client-ip=79.135.106.28 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=proton.me Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=proton.me Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=proton.me header.i=@proton.me header.b="OuvlnTKG" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=proton.me; s=6jba5to2fzf2tmn4smqyqpdmoq.protonmail; t=1742345439; x=1742604639; bh=VkL2Mxif+LYFPEMvRY4YuHUJQ31AetP3+c0xD9LJp+0=; h=Date:To:From:Cc:Subject:Message-ID:In-Reply-To:References: Feedback-ID:From:To:Cc:Date:Subject:Reply-To:Feedback-ID: Message-ID:BIMI-Selector:List-Unsubscribe:List-Unsubscribe-Post; b=OuvlnTKGDYLlG88upDBw7wr7g3AGCYM0aTNk3kRAoVprUuW+CF/kqquXw1cSicdLT uVn/H329nesx/xyayy2Fazl1UVyHZV/K9jTFAG2dKFAG0dRAq2X9EKmPTvy44/LhqH UHiRD60+7g1KXwgS4aJRWHPWE1eO7El1z6MIJnTGMDd/5NPPy77oQsWCNSa40MHR0S +WoI4I0EQk/x2iIHvxkVkXQ4zY4IbT36G7wYMVsFjOsIpmc8INPwpP/zzcrIZZVBJD ylra/qToQwv/F1EBGmh2weZubQEmvOe9vyQrqoJEt34Dm4R4WYR1Ork8tDUjgM+Fbl mmXzZ4qWCyItw== Date: Wed, 19 Mar 2025 00:50:29 +0000 To: Tamir Duberstein , Andrew Ballance From: Benno Lossin Cc: dakr@kernel.org, airlied@gmail.com, simona@ffwll.ch, maarten.lankhorst@linux.intel.com, mripard@kernel.org, tzimmermann@suse.de, corbet@lwn.net, ojeda@kernel.org, alex.gaynor@gmail.com, boqun.feng@gmail.com, gary@garyguo.net, bjorn3_gh@protonmail.com, a.hindborg@kernel.org, aliceryhl@google.com, tmgross@umich.edu, acourbot@nvidia.com, nouveau@lists.freedesktop.org, dri-devel@lists.freedesktop.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, rust-for-linux@vger.kernel.org Subject: Re: [PATCH v2 2/3] rust: alloc: add Vec::resize method Message-ID: In-Reply-To: References: <20250316111644.154602-1-andrewjballance@gmail.com> <20250316111644.154602-3-andrewjballance@gmail.com> Feedback-ID: 71780778:user:proton X-Pm-Message-ID: 124220e04b60981fd23d64c8176e2b18357079aa 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 On Tue Mar 18, 2025 at 9:12 PM CET, Tamir Duberstein wrote: > On Sun, Mar 16, 2025 at 7:17=E2=80=AFAM Andrew Ballance > wrote: >> + pub fn resize(&mut self, new_len: usize, value: T, flags: Flags) ->= Result<(), AllocError> { >> + if new_len > self.len() { >> + self.extend_with(new_len - self.len(), value, flags) >> + } else { >> + self.truncate(new_len); >> + Ok(()) >> + } >> + } > > You can avoid underflow checking in debug builds by using `checked_sub`: `checked_sub` doesn't only avoid underflow in debug builds, but rather in all builds. But the code below is a good suggestion. --- Cheers, Benno > match new_len.checked_sub(self.len()) { > Some(n) =3D> self.extend_with(n, value, flags), > None =3D> { > self.truncate(new_len); > Ok(()) > } > } > >> } >> >> impl Drop for Vec >> -- >> 2.48.1 >> >> > > Either way: > > Reviewed-by: Tamir Duberstein