linux-kernel - Re: pr_* versus dev

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <1269967960.4558.162.camel@Joe-Laptop.home>
Date:	Tue, 30 Mar 2010 09:52:40 -0700
From:	Joe Perches <joe@...ches.com>
To:	Neshama Parhoti <pneshama@...il.com>
Cc:	linux-kernel@...r.kernel.org
Subject: Re: pr_* versus dev_*

On Tue, 2010-03-30 at 19:07 +0300, Neshama Parhoti wrote:
> Which set of macros should I use in my driver ?
> 
> pr_info, pr_err, etc...  or dev_info, dev_err,    etc. ?

Possibly all of them.

> what are the advantages of the dev_* macros over the pr_* macros
> (why does it take the device pointer as an argument) ?
> 
> obviously I don't have access to my device pointer in all my functions..
> so pr_info is easier to use..
> but if it's wanted, obviously I can arrange to have my device pointer
> accessible..

You should also use dev_<level> where possible.
You should also use netdev_<level> and netif_<level> if your
device is a networking driver.
You should #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
to have a standard prefix for your driver.

Function	Benefit

pr_<level>:	Slightly shorter than printk(KERN_<LEVEL>)
		Gets a standard prefix with pr_fmt
dev_<level>:	Standardized device information:
		dev_driver_string, then dev_name
		dev_driver_string is the device's driver's name
		if it is bound to a device.  If the device is not
		bound to a device, the name of the bus it is
		attached to.  If it is not attached to a bus but
		has a class, the class name.
		If no class, you'll find an empty dance card.
netdev_<level>:	Appends struct net_device.name to dev_<level> prefix
		Use dev_<level> until alloc_netdev or alloc_etherdev
		has been called successfully.
netif_<level>:	Test network interface message level (netif_msg_<foo>)
		before calling netdev_<level>

Message logging with KERN_DEBUG levels are a bit more complicated:

These calls are optimized away and never printed unless
DEBUG is #defined or CONFIG_DYNAMIC_DEBUG is enabled.

pr_debug
dev_dbg
netdev_dbg
netif_dbg

To always have these emitted, use the appropriate printk calls

printk(KERN_DEBUG	this does not get a standard prefix
			use printk(KERN_DEBUG pr_fmt(fmt) if desired
dev_printk(KERN_DEBUG
netdev_printk(KERN_DEBUG
netif_printk(priv, msg, KERN_DEBUG

There are  _vdbg variants for even more verbose output if
VERBOSE_DEBUG is #defined.

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/