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 A9E95C83003 for ; Fri, 9 Jun 2023 13:15:08 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S241141AbjFINPG (ORCPT ); Fri, 9 Jun 2023 09:15:06 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38596 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S241128AbjFINPF (ORCPT ); Fri, 9 Jun 2023 09:15:05 -0400 Received: from mail-yb1-xb49.google.com (mail-yb1-xb49.google.com [IPv6:2607:f8b0:4864:20::b49]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1A26C132 for ; Fri, 9 Jun 2023 06:15:04 -0700 (PDT) Received: by mail-yb1-xb49.google.com with SMTP id 3f1490d57ef6-bbad78c36d6so2324727276.1 for ; Fri, 09 Jun 2023 06:15:04 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20221208; t=1686316503; x=1688908503; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=r/XZ6SC2BfwM1Yl5yWo3TP60rpG2To/FFxUz60d/enM=; b=v2B2JCU60YU5jdpuYXWNKaYC8T1/AJ+Dx6iVUh33Ky7qKj2+X9AQp9F+dPEEY3F9bj N52pdfzb1ayxQWdQGeupWCgNlnRxU2ms2K5idF9v3ZCU5lQ5fowyKMT1SUWKx5UhW2XB 24mFv44qpwwSzUCYGZ6LZPl5zY5j/IU4izrntufUZr10RQy3+Stk1LWUAE8xzOWc2boy STyesmoPpOoN0+zLl6UHfO/XULFRZYAzd9x9G+L1Z5NOlzVd0/FMhGauU8z+8nBgi3hi EIU9awx0VUIQQ0t68nWjPd3R8FD2vpOqsS2mR6hpK1/RivhZdJ0EMPegtrQFySQP/Tyi pDIQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1686316503; x=1688908503; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=r/XZ6SC2BfwM1Yl5yWo3TP60rpG2To/FFxUz60d/enM=; b=cGFTnqfAc8hlapBSjtwhAVGwL68LfzsSVwIY36oqU7ugw2Vux2zDerlYzkG73QoL6T zwgxNu6R0w5KtX8s988JIg3UHE3QwWXY5+7N7HivLqN8DyeRRJEzgnnaMAE7lXam1V53 G6i64ZPYXaZzey7txuWCaaGpfoVRAOoKdgFue17dq+7TIJh2iKANSZN/7fFbjg5aztbm CfsM64qOQF4kGkJZVKelhyyce3oGbfR2lJyTaiCE3saIKPcChi/qqXogJurEso0p019x /SO7C0CsXXePJTH9GdOTzTOAe06nN8gcZfRkUKLe9gpPFbCXFmCoY+r2TUpIXud5Qj1l U5WQ== X-Gm-Message-State: AC+VfDy5Hr1V+xS/ECVeaW6bUZJ20lZGRYu8U8DhsJjJwHcOhiZUvhot 8W+0L4L9aiXaVYng9GZVIW8jf2ERqoSRXaY= X-Google-Smtp-Source: ACHHUZ57dtXYPY0QY0nIS78c5VZsBuHMMmgAId1O6LPBqj+tK+B17YCRV3xZMCaXMIsGn4RPWUfckLqW6acZtIw= X-Received: from aliceryhl.c.googlers.com ([fda3:e722:ac3:cc00:31:98fb:c0a8:6c8]) (user=aliceryhl job=sendgmr) by 2002:a25:fb05:0:b0:bc1:dfa5:83a8 with SMTP id j5-20020a25fb05000000b00bc1dfa583a8mr307882ybe.10.1686316503324; Fri, 09 Jun 2023 06:15:03 -0700 (PDT) Date: Fri, 9 Jun 2023 13:15:00 +0000 In-Reply-To: <20230604124735.1378859-1-aliceryhl@google.com> Mime-Version: 1.0 References: <20230604124735.1378859-1-aliceryhl@google.com> X-Mailer: git-send-email 2.41.0.162.gfafddb0af9-goog Message-ID: <20230609131500.1646742-1-aliceryhl@google.com> Subject: Re: [PATCH 1/5] rust: core abstractions for network device drivers From: Alice Ryhl To: aliceryhl@google.com Cc: fujita.tomonori@gmail.com, rust-for-linux@vger.kernel.org, tomo@exabit.dev Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: rust-for-linux@vger.kernel.org FUJITA Tomonori writes: > On Thu, 8 Jun 2023 07:38:07 +0000 > Alice Ryhl wrote: > >>>>> + const DEVICE_OPS: bindings::net_device_ops = bindings::net_device_ops { >>>>> + ndo_init: if ::HAS_INIT { >>>>> + Some(Self::init_callback) >>>>> + } else { >>>>> + None >>>>> + }, >>>>> + ndo_uninit: if ::HAS_UNINIT { >>>>> + Some(Self::uninit_callback) >>>>> + } else { >>>>> + None >>>>> + }, >>>>> + ndo_open: if ::HAS_OPEN { >>>>> + Some(Self::open_callback) >>>>> + } else { >>>>> + None >>>>> + }, >>>>> + ndo_stop: if ::HAS_STOP { >>>>> + Some(Self::stop_callback) >>>>> + } else { >>>>> + None >>>>> + }, >>>>> + ndo_start_xmit: if ::HAS_START_XMIT { >>>>> + Some(Self::start_xmit_callback) >>>>> + } else { >>>>> + None >>>>> + }, >>>>> + ndo_features_check: None, >>>>> + ndo_select_queue: None, >>>>> + ndo_change_rx_flags: None, >>>>> + ndo_set_rx_mode: None, >>>>> + ndo_set_mac_address: None, >>>> >>>> Bindgen is set up to generate `Default` implementations for these types, >>>> so you can do this to omit the remaining fields: >>> >>> It can work with const? >> >> Ah, no, good point. >> >> However, you could use `unsafe { mem::zeroed() }` instead. > > I can't figure out a way to make mem::zeroed() with const but looks > like the following similar way works. > > const DEVICE_OPS: bindings::net_device_ops = { > let mut ops = unsafe { > core::mem::MaybeUninit::::zeroed().assume_init() }; > > if ::HAS_UNINIT { > ops.ndo_init = Some(Self::init_callback); > } > ops > }; > > thanks, You can also write: ``` const DEVICE_OPS: bindings::net_device_ops = bindings::net_device_ops { ndo_init: if ::HAS_INIT { Some(Self::init_callback) } else { None }, ndo_uninit: if ::HAS_UNINIT { Some(Self::uninit_callback) } else { None }, ndo_open: if ::HAS_OPEN { Some(Self::open_callback) } else { None }, ndo_stop: if ::HAS_STOP { Some(Self::stop_callback) } else { None }, ndo_start_xmit: if ::HAS_START_XMIT { Some(Self::start_xmit_callback) } else { None }, ..unsafe { core::mem::MaybeUninit::::zeroed().assume_init() } }; ``` Alice