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 816CFC4332F for ; Mon, 17 Oct 2022 12:01:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229963AbiJQMBM (ORCPT ); Mon, 17 Oct 2022 08:01:12 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54494 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229977AbiJQMA7 (ORCPT ); Mon, 17 Oct 2022 08:00:59 -0400 Received: from mail-wr1-x42d.google.com (mail-wr1-x42d.google.com [IPv6:2a00:1450:4864:20::42d]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B4F781580F for ; Mon, 17 Oct 2022 05:00:58 -0700 (PDT) Received: by mail-wr1-x42d.google.com with SMTP id a3so18185112wrt.0 for ; Mon, 17 Oct 2022 05:00:58 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=content-transfer-encoding:content-language:in-reply-to:mime-version :user-agent:date:message-id:from:references:cc:to:subject:from:to:cc :subject:date:message-id:reply-to; bh=ZQjdJoe4vEi5m/yPvqEKdDmDRBjEwza9oxlp08KcxmU=; b=cn4w53qiJZgKdTaw35xWqNbueWk5afGvwFShqHZEDDe7QPQt3UVnjCXhfjPlWyohWU h7c70XCcTUqretwtT5BzikWXar2NLkVlocb1K12d+f7RncO9v5tJV3HLGH38duuZCXAi 8T7pQnyFpovFnXIZn6RF+Rlaf2o5AQmbYPvCVUkOsnQUPh3dOBJE2TaNEdW6rithfYM6 zNiVMaEyLbyx1m4LMPw1qXfrV/DrWM36ha3jvctUzV0QqOPFut1n5TGcIsY2EyDJnvqM n2ptc1VcIU+/77TEgn9WLb1X0dUNE7l7djLsCCCvLAaLz8NvQid/GxjXrtD3Eba2QBR7 P8+Q== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=content-transfer-encoding:content-language:in-reply-to:mime-version :user-agent:date:message-id:from:references:cc:to:subject :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=ZQjdJoe4vEi5m/yPvqEKdDmDRBjEwza9oxlp08KcxmU=; b=SOs/kz6jJmaB1+Gvdwbyh9wJi49IHIdvX/rxjAiXZw2i8hce0CdivSq96nkP0Q9CQF pfI7KlfBFaKMrW7M+fDT1QnVg0RSkTHl3Dn72PiIl4V/0alzS9t4SOogUuyH9kuaDT2q 8NEBZ1caRtUbRogsQraFsnmQ5YfbNf1Sb4x2iu56nnZQQNwu1JAwonSJvCpMNjrBb+BC tkioBfXW42JzNP+EAdjiLw2ScWRlN57jifgaqU+xQGuQDO4i7WbAVMf6t4mpwUe8GehT sC5JmlPgLKA5ZTQZlEuKVkENZxdalecJieQUebRcsbMSk0PFq73Fs0PhGqO7cwg5DIwF 4sKQ== X-Gm-Message-State: ACrzQf12UxBWyxop0tSB0T2y2zkJ8LjbgwzXXMC4agfyYc+BQfHHXCXF QNSMOi3Sz+SQr9KY+acOjDI= X-Google-Smtp-Source: AMsMyM4Zv8PtKEoHHFhs4qb2XAXW21Qm3XyQehmTsj4nQmBjHCisix+DyIUw64WyP0T5Fjch8gGXpg== X-Received: by 2002:a5d:5744:0:b0:22d:9b90:a8fe with SMTP id q4-20020a5d5744000000b0022d9b90a8femr5910097wrw.144.1666008057147; Mon, 17 Oct 2022 05:00:57 -0700 (PDT) Received: from [192.168.1.122] (cpc159313-cmbg20-2-0-cust161.5-4.cable.virginm.net. [82.0.78.162]) by smtp.gmail.com with ESMTPSA id l19-20020a05600c089300b003c409244bb0sm9837270wmp.6.2022.10.17.05.00.56 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 17 Oct 2022 05:00:56 -0700 (PDT) Subject: Re: [RFC PATCH net-next 1/3] netlink: add support for formatted extack messages To: Jiri Pirko , ecree@xilinx.com Cc: netdev@vger.kernel.org, linux-net-drivers@amd.com, davem@davemloft.net, kuba@kernel.org, pabeni@redhat.com, edumazet@google.com, habetsm.xilinx@gmail.com, johannes@sipsolutions.net, marcelo.leitner@gmail.com References: From: Edward Cree Message-ID: <43513470-fd59-4d18-f66e-0aecfcfc8404@gmail.com> Date: Mon, 17 Oct 2022 13:00:55 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.14.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-GB Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On 13/10/2022 13:55, Jiri Pirko wrote: > Fri, Oct 07, 2022 at 03:25:12PM CEST, ecree@xilinx.com wrote: >> #define NL_SET_ERR_MSG_MOD(extack, msg) \ >> NL_SET_ERR_MSG((extack), KBUILD_MODNAME ": " msg) >> >> +#define NL_SET_ERR_MSG_FMT_MOD(extack, fmt, args...) \ > > I wonder, wouldn't it be better to just have NL_SET_ERR_MSG_MOD which > accepts format string and that's it. I understand there is an extra > overhead for the messages that don't use formatting, but do we care? > This is no fastpath and usually happens only seldom. The API towards > the driver would be more simple. Could do, but this way a fixed string isn't limited to NETLINK_MAX_FMTMSG_LEN like it would be if we tried to stuff it in _msg_buf. Unless you're suggesting some kind of macro magic that detects whether args is empty and chooses which implementation to use, but that seems like excessive hidden cleverness — better to have driver authors aware of the limitations of each choice. > I like this a lot! :)