Re: [PATCH] wan: dscc4: use msecs_to_jiffies for conversions

From: Nicholas Mc Guire
Date: Sun Jun 07 2015 - 04:32:14 EST


On Sun, 07 Jun 2015, David Miller wrote:

> From: Nicholas Mc Guire <hofrat@xxxxxxxxx>
> Date: Sat, 6 Jun 2015 10:41:06 +0200
>
> > API compliance scanning with coccinelle flagged:
> > ./drivers/net/wan/dscc4.c:1036:1-33:
> > WARNING: timeout (10) seems HZ dependent
> > ./drivers/net/wan/dscc4.c:554:2-34:
> > WARNING: timeout (10) seems HZ dependent
> > ./drivers/net/wan/dscc4.c:599:2-34:
> > WARNING: timeout (10) seems HZ dependent
> >
> > Numeric constants passed to schedule_timeout_*() make the effective
> > timeout HZ dependent which does not seem to be the intent here.
> > Fixed up by converting the constant to jiffies with msecs_to_jiffies()
> >
> > Signed-off-by: Nicholas Mc Guire <hofrat@xxxxxxxxx>
>
> Whoever wrote these things probably wanted whatever this amounts
> to when HZ=100, so that is the only valid transformation you can
> make to fix this up here.
>
> Otherwise you seriously risk breaking the driver.

I did not find dscc4 in the 2.2 series of kernels so it does not predate
configurable HZ - or do you mean simply that increasing the timeout
here should be side-effect free and thus the larger of the values
should be taken ? - though that would imply that it is possibly now
broken for HZ=1000.

Will fix it up to 10 == 100ms and fix the patch documentation.

thx!
hofrat
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