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
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
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