Linux-Block Archive on lore.kernel.org
 help / color / Atom feed
From: "André Almeida" <andrealmeid@collabora.com>
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,
	"André Almeida" <andrealmeid@collabora.com>
Subject: [PATCH v2 4/4] coding-style: add explanation about pr_fmt macro
Date: Fri, 13 Sep 2019 19:03:00 -0300
Message-ID: <20190913220300.422869-5-andrealmeid@collabora.com> (raw)
In-Reply-To: <20190913220300.422869-1-andrealmeid@collabora.com>

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 <andrealmeid@collabora.com>
Cc: Jonathan Corbet <corbet@lwn.net>
---
Changes from v1:
- Add Jonathan as explict Cc
- Replace "include/printk.h" by "#include <linux/kernel.h>
- Add note about #undef
- Replace hardcore string by KBUILD_MODNAME at the example
---
 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..1a33a933fbd3 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, <linux/printk.h> 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 ``#include <linux/kernel.h>``, to avoid compiler warning about
+redefinitions, or just use ``#undef pr_fmt``. 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) KBUILD_MODNAME ": " 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


  parent reply index

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-09-13 22:02 [PATCH v2 0/4] null_blk: fixes around nr_devices and log improvements André Almeida
2019-09-13 22:02 ` [PATCH v2 1/4] null_blk: do not fail the module load with zero devices André Almeida
2019-09-13 22:15   ` Chaitanya Kulkarni
2019-09-13 22:17   ` Bart Van Assche
2019-09-13 22:37     ` Chaitanya Kulkarni
2019-09-13 22:02 ` [PATCH v2 2/4] null_blk: match the type of parameter nr_devices André Almeida
2019-09-13 22:15   ` Chaitanya Kulkarni
2019-09-13 22:02 ` [PATCH v2 3/4] null_blk: format pr_* logs with pr_fmt André Almeida
2019-09-13 22:16   ` Chaitanya Kulkarni
2019-09-13 22:03 ` André Almeida [this message]
2019-09-13 22:18   ` [PATCH v2 4/4] coding-style: add explanation about pr_fmt macro Chaitanya Kulkarni
2019-09-14  7:50   ` Jonathan Corbet
2019-09-16 13:38     ` André Almeida

Reply instructions:

You may reply publically to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20190913220300.422869-5-andrealmeid@collabora.com \
    --to=andrealmeid@collabora.com \
    --cc=axboe@kernel.dk \
    --cc=corbet@lwn.net \
    --cc=kernel@collabora.com \
    --cc=krisman@collabora.com \
    --cc=linux-block@vger.kernel.org \
    --cc=linux-doc@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

Linux-Block Archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lore.kernel.org/linux-block/0 linux-block/git/0.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 linux-block linux-block/ https://lore.kernel.org/linux-block \
		linux-block@vger.kernel.org linux-block@archiver.kernel.org
	public-inbox-index linux-block


Newsgroup available over NNTP:
	nntp://nntp.lore.kernel.org/org.kernel.vger.linux-block


AGPL code for this site: git clone https://public-inbox.org/ public-inbox