On Tue, 4 Jul 2017 12:40:33 +0200
Geert Uytterhoeven <geert@xxxxxxxxxxxxxx> wrote:
> Hi Nicholas,
>
> On Sun, May 14, 2017 at 10:43 AM, Nicholas Mc Guire <der.herr@xxxxxxx> wrote:
> > If the timeout-case prints a warning message then probably the interrupted
> > case should also. Further, wait_for_completion_interruptible_timeout()
> > returns long not int.
> >
> > Fixes: commit 03b262f2bbf4 ("iio:pressure: initial zpa2326 barometer support")
> > Signed-off-by: Nicholas Mc Guire <der.herr@xxxxxxx>
> > ---
> >
> > The original control-flow was technically not wrong just confusing and a bit
> > complicated. Not clear if reporting the interrupted case actually is useful,
> > but given that the timeout is relatively long (200ms) it is not that unlikely
> > so differentiating the cases seems helpful.
> >
> > Patch was compile-tested with: x86_64_defconfig + CONFIG_IIO=m, CONFIG_ZPA2326=m
> >
> > Patch is against v4.11 (localversion-next is next-20170512)
> >
> > drivers/iio/pressure/zpa2326.c | 17 ++++++++++-------
> > 1 file changed, 10 insertions(+), 7 deletions(-)
> >
> > diff --git a/drivers/iio/pressure/zpa2326.c b/drivers/iio/pressure/zpa2326.c
> > index e58a0ad..617926f 100644
> > --- a/drivers/iio/pressure/zpa2326.c
> > +++ b/drivers/iio/pressure/zpa2326.c
> > @@ -867,12 +867,13 @@ static int zpa2326_wait_oneshot_completion(const struct iio_dev *indio_dev,
> > {
> > int ret;
> > unsigned int val;
> > + long timeout;
> >
> > zpa2326_dbg(indio_dev, "waiting for one shot completion interrupt");
> >
> > - ret = wait_for_completion_interruptible_timeout(
> > + timeout = wait_for_completion_interruptible_timeout(
> > &private->data_ready, ZPA2326_CONVERSION_JIFFIES);
> > - if (ret > 0)
> > + if (timeout > 0)
>
> Check for strict positive timeout.
>
> > /*
> > * Interrupt handler completed before timeout: return operation
> > * status.
> > @@ -882,13 +883,15 @@ static int zpa2326_wait_oneshot_completion(const struct iio_dev *indio_dev,
> > /* Clear all interrupts just to be sure. */
> > regmap_read(private->regmap, ZPA2326_INT_SOURCE_REG, &val);
> >
> > - if (!ret)
> > + if (!timeout) {
>
> Check for zero timeout.
>
> > /* Timed out. */
> > + zpa2326_warn(indio_dev, "no one shot interrupt occurred (%ld)",
> > + timeout);
> > ret = -ETIME;
> > -
> > - if (ret != -ERESTARTSYS)
> > - zpa2326_warn(indio_dev, "no one shot interrupt occurred (%d)",
> > - ret);
> > + } else if (timeout < 0) {
>
> So if we get here, timeout is always strict negative, so the check can
> be removed.
>
> > + zpa2326_warn(indio_dev, "wait for one shot interrupt canceled");
> > + ret = -ERESTARTSYS;
> > + }
> >
> > return ret;
>
> But gcc-4.1.2 is not smart enough:
>
> drivers/iio/pressure/zpa2326.c:868: warning: ‘ret’ may be used
> uninitialized in this function
Good analysis. Care to send the obvious patch?
J
>
> 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
> --
> To unsubscribe from this list: send the line "unsubscribe linux-iio" in
> the body of a message to majordomo@xxxxxxxxxxxxxxx
> More majordomo info at http://vger.kernel.org/majordomo-info.html
--
To unsubscribe from this list: send the line "unsubscribe linux-iio" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
