Hi Geert,
(thanks for adding Joe to Cc:, I noticed that when I wanted to add him
myself :-)
On Sun, Dec 18, 2011 at 11:32:21AM +0100, Geert Uytterhoeven wrote:
> 2011/12/17 Uwe Kleine-König <u.kleine-koe...@pengutronix.de>:
> > Using pr_crit in an header results in funny messages. Consider
> >
> > #define pr_fmt(fmt) "mydriver: " fmt
> > #include <linux/hardirq.h>
> >
> > which makes the message from ack_bad_irq
> >
> > mydriver: unexpected IRQ trap...
> >
> > so better use plain printk with KERN_CRIT directly.
>
> Yep, that's expected behavior, as defining pr_fmt() modifies all kernel
> messages
> generated from that module.
I'm aware it is expected, I only wondered if it is also desirable to
have messages in headers modified depending on the module the header is
included in.
> > This fixes a build problem on m68k with aufs3 en passant because the
> > latter builds with
> >
> > ccflags-y +=
> > -D'pr_fmt(fmt)=AUFS_NAME"\040%s:%d:%s[%d]:\040"fmt,__func__,__LINE__,current->comm,current->pid'
> >
> > without providing AUFS_NAME early enough for ack_bad_irq (which is the
> > problem of aufs).
>
> Isn't this a problem with (out of tree) aufs?
> Why does it put a define that relies on an (apparently sometimes still
> undefined)
> variable on the build command line?
This is definitily a bug in aufs that needs fixing independant of the
issue of using or not using pr_... in headers.
> Any header may contain calls to pr_*().
>
> > Cc: Thorsten Glaser <t...@debian.org>
> > Signed-off-by: Uwe Kleine-König <u.kleine-koe...@pengutronix.de>
> > ---
> > arch/m68k/include/asm/hardirq.h | 2 +-
> > 1 files changed, 1 insertions(+), 1 deletions(-)
> >
> > diff --git a/arch/m68k/include/asm/hardirq.h
> > b/arch/m68k/include/asm/hardirq.h
> > index db30ed2..1f652e0 100644
> > --- a/arch/m68k/include/asm/hardirq.h
> > +++ b/arch/m68k/include/asm/hardirq.h
> > @@ -20,7 +20,7 @@
> >
> > static inline void ack_bad_irq(unsigned int irq)
> > {
> > - pr_crit("unexpected IRQ trap at vector %02x\n", irq);
> > + printk(KERN_CRIT "unexpected IRQ trap at vector %02x\n", irq);
>
> Nack. Nowadays pr_crit(...) is recommended over "printk(KERN_CRIT ...)".
I know that, I just wonder if the proponents of this recommendation are
aware of the issue when using pr_* in headers. Joe?
> Besides, there are (albeit not that many yet) other callers of pr_*() in
> header files. Do you plan to revert them to printk(), too?
That depends on the outcome of this discussion.
> Please fix aufs instead. Thanks!
I already provided a patch for that, too. (Currently only on the Debian
kernel ML.)
Best regards
Uwe
--
Pengutronix e.K. | Uwe Kleine-König |
Industrial Linux Solutions | http://www.pengutronix.de/ |
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