Messages in this thread | | | From | Geert Uytterhoeven <> | Date | Tue, 4 Jul 2017 12:40:33 +0200 | Subject | Re: [PATCH RFC] iio: pressure: zpa2326: report interrupted case as failure |
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Hi Nicholas,
On Sun, May 14, 2017 at 10:43 AM, Nicholas Mc Guire <der.herr@hofr.at> 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@hofr.at> > --- > > 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
Gr{oetje,eeting}s,
Geert
-- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org
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
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