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 X-Spam-Level: X-Spam-Status: No, score=-10.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 9EF3BC4CEC8 for ; Fri, 13 Sep 2019 18:59:23 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 79D9F2081B for ; Fri, 13 Sep 2019 18:59:23 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388220AbfIMS7V (ORCPT ); Fri, 13 Sep 2019 14:59:21 -0400 Received: from bhuna.collabora.co.uk ([46.235.227.227]:59214 "EHLO bhuna.collabora.co.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726822AbfIMS7N (ORCPT ); Fri, 13 Sep 2019 14:59:13 -0400 Received: from turingmachine.home (unknown [IPv6:2804:431:c7f4:5bfc:5711:794d:1c68:5ed3]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) (Authenticated sender: tonyk) by bhuna.collabora.co.uk (Postfix) with ESMTPSA id 62B5928F197; Fri, 13 Sep 2019 19:59:08 +0100 (BST) From: =?UTF-8?q?Andr=C3=A9=20Almeida?= To: linux-block@vger.kernel.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org Cc: corbet@lwn.net, axboe@kernel.dk, kernel@collabora.com, krisman@collabora.com, =?UTF-8?q?Andr=C3=A9=20Almeida?= Subject: [PATCH 4/4] coding-style: add explanation about pr_fmt macro Date: Fri, 13 Sep 2019 15:57:46 -0300 Message-Id: <20190913185746.337429-5-andrealmeid@collabora.com> X-Mailer: git-send-email 2.23.0 In-Reply-To: <20190913185746.337429-1-andrealmeid@collabora.com> References: <20190913185746.337429-1-andrealmeid@collabora.com> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The pr_fmt macro is useful to format log messages printed by pr_XXXX() functions. Add text to explain the purpose of it, how to use and an example. Signed-off-by: André Almeida --- Documentation/process/coding-style.rst | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-) diff --git a/Documentation/process/coding-style.rst b/Documentation/process/coding-style.rst index f4a2198187f9..276787bc2ff2 100644 --- a/Documentation/process/coding-style.rst +++ b/Documentation/process/coding-style.rst @@ -819,7 +819,15 @@ which you should use to make sure messages are matched to the right device and driver, and are tagged with the right level: dev_err(), dev_warn(), dev_info(), and so forth. For messages that aren't associated with a particular device, defines pr_notice(), pr_info(), -pr_warn(), pr_err(), etc. +pr_warn(), pr_err(), etc. It's possible to format pr_XXX() messages using the +macro pr_fmt() to prevent rewriting the style of messages. It should be +defined before including ``include/printk.h``, to avoid compiler warning about +redefinitions. This is particularly useful for adding the name of the module at +the beginning of the message, for instance: + +.. code-block:: c + + #define pr_fmt(fmt) "module_name: " fmt Coming up with good debugging messages can be quite a challenge; and once you have them, they can be a huge help for remote troubleshooting. However -- 2.23.0