Hi Leon,
On Thu, Nov 17, 2022 at 10:14 AM Leon Romanovsky <leon@xxxxxxxxxx> wrote:
> On Thu, Nov 17, 2022 at 09:59:55AM +0100, Geert Uytterhoeven wrote:
> > On Thu, Nov 17, 2022 at 9:58 AM Yoshihiro Shimoda
> > <yoshihiro.shimoda.uh@xxxxxxxxxxx> wrote:
> > > > From: Leon Romanovsky, Sent: Thursday, November 17, 2022 3:09 PM
> > > > > --- a/drivers/net/ethernet/renesas/rswitch.c
> > > > > +++ b/drivers/net/ethernet/renesas/rswitch.c
> > > > > @@ -1714,7 +1714,7 @@ static int rswitch_init(struct rswitch_private *priv)
> > > > > }
> > > > >
> > > > > for (i = 0; i < RSWITCH_NUM_PORTS; i++)
> > > > > - netdev_info(priv->rdev[i]->ndev, "MAC address %pMn",
> > > > > + netdev_info(priv->rdev[i]->ndev, "MAC address %pM\n",
> > > >
> > > > You can safely drop '\n' from here. It is not needed while printing one
> > > > line.
> > >
> > > Oh, I didn't know that. I'll remove '\n' from here on v2 patch.
> >
> > Please don't remove it. The convention is to have the newlines.
>
> Can you please explain why?
I'm quite sure this was discussed in the context of commits
5fd29d6ccbc98884 ("printk: clean up handling of log-levels and
newlines") and 4bcc595ccd80decb ("printk: reinstate KERN_CONT for
printing continuation lines"), but I couldn't find a pointer to an
official statement.
I did find[1], which states:
The printk subsystem will, for every printk, check
if the last printk has a newline termination and if
it doesn't and the current printk does not start with
KERN_CONT will insert a newline.
The negative to this approach is the last printk,
if it does not have a newline, is buffered and not
emitted until another printk occurs.
There is also the (now small) possibility that
multiple concurrent kernel threads or processes
could interleave printks without a terminating
newline and a different process could emit a
printk that starts with KERN_CONT and the emitted
message could be garbled.
[1] https://lore.kernel.org/all/b867ee8a02043ec6b18c9330bfe3a091d66c816c.camel@xxxxxxxxxxx
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx
In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds
