Re: [PATCH v11 04/33] counter: 104-quad-8: Return error when invalid mode during ceiling_write

From: William Breathitt Gray
Date: Wed Jun 09 2021 - 11:48:28 EST


On Wed, Jun 09, 2021 at 04:12:36PM +0100, Jonathan Cameron wrote:
> On Wed, 9 Jun 2021 10:31:07 +0900
> William Breathitt Gray <vilhelm.gray@xxxxxxxxx> wrote:
>
> > The 104-QUAD-8 only has two count modes where a ceiling value makes
> > sense: Range Limit and Modulo-N. Outside of these two modes, setting a
> > ceiling value is an invalid operation -- so let's report it as such by
> > returning -EINVAL.
> >
> > Fixes: fc069262261c ("counter: 104-quad-8: Add lock guards - generic interface")
> > Acked-by: Syed Nayyar Waris <syednwaris@xxxxxxxxx>
> > Signed-off-by: William Breathitt Gray <vilhelm.gray@xxxxxxxxx>
>
> We seem to have some inconsistency in the driver about whether
> we hold the priv->lock when calling quad8_preset_register_set()
>
> Can we look to make that consistent?

We do need to hold the lock when calling quad8_preset_register_set()
lest priv->preset goes out of sync with the device state.

Syed, if you have no objections I'll adjust this in the next version.

William Breathitt Gray

> > ---
> > drivers/counter/104-quad-8.c | 5 +++--
> > 1 file changed, 3 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/counter/104-quad-8.c b/drivers/counter/104-quad-8.c
> > index 4bb9abffae48..233a3acc1377 100644
> > --- a/drivers/counter/104-quad-8.c
> > +++ b/drivers/counter/104-quad-8.c
> > @@ -714,13 +714,14 @@ static ssize_t quad8_count_ceiling_write(struct counter_device *counter,
> > switch (priv->count_mode[count->id]) {
> > case 1:
> > case 3:
> > + mutex_unlock(&priv->lock);
>
> Probably swap this line and the next one...]
>
> > quad8_preset_register_set(priv, count->id, ceiling);
> > - break;
> > + return len;
> > }
> >
> > mutex_unlock(&priv->lock);
> >
> > - return len;
> > + return -EINVAL;
> > }
> >
> > static ssize_t quad8_count_preset_enable_read(struct counter_device *counter,
>

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