linux-kernel - Re: [PATCH v5] printk: Userspace format enumeration support

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Date:   Mon, 19 Apr 2021 11:53:37 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     Petr Mladek <pmladek@...e.com>
Cc:     Rasmus Villemoes <linux@...musvillemoes.dk>,
        Chris Down <chris@...isdown.name>,
        linux-kernel@...r.kernel.org,
        Sergey Senozhatsky <sergey.senozhatsky@...il.com>,
        John Ogness <john.ogness@...utronix.de>,
        Johannes Weiner <hannes@...xchg.org>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Steven Rostedt <rostedt@...dmis.org>,
        Kees Cook <keescook@...omium.org>, kernel-team@...com
Subject: Re: [PATCH v5] printk: Userspace format enumeration support

On Mon, Apr 19, 2021 at 11:16:43AM +0200, Petr Mladek wrote:
> On Mon 2021-04-19 09:27:43, Rasmus Villemoes wrote:
> > On 16/04/2021 15.56, Chris Down wrote:
> > > Hey Petr, Rasmus,
> > 
> > >> This is great point! There are many other subsystem specific wrappers,
> > >> e,g, ata_dev_printk(), netdev_printk(), snd_printk(), dprintk().
> > >> We should make it easy to index them as well.
> > > 
> > > These would be nice to have, but we should agree about how we store
> > > things internally.
> > > 
> > > For example, in printk we typically store the level inline as part of
> > > the format string at compile time. However, for `dev_printk`, it's
> > > passed entirely separately from the format string after preprocessing is
> > > already concluded (or at least, not in a way we can easily parse it the
> > > same way we do for printk()):
> > > 
> > >     void dev_printk(const char *level, const struct device *dev, const
> > > char *fmt, ...)
> > 
> > Hm, yeah, for "naked" dev_printk() calls there's no easy way to grab the
> > level, for dev_err and friends it's somewhat easier as you could just
> > hook into the definition of the dev_err macro. I'm not saying you need
> > to handle everything at once, but doing dev_err and netdev_err would get
> > you a very long way
> 
> It is true that there are many messages printed using
> dev_printk(). For example, these rough numbers:
> 
> $> git grep pr_err | wc -l
> 19885
> $> git grep dev_err | wc -l
> 58153

You need "-w" :)

And I bet most of those pr_err() should be turned into dev_err(), if
they live in drivers/.

Hm, 12734 of the pr_err() calls do live in drivers/, so most of those
should be dev_err().  Might be something good to throw at interns...

thanks,

greg k-h