Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752816AbdGDKkj (ORCPT ); Tue, 4 Jul 2017 06:40:39 -0400 Received: from mail-io0-f195.google.com ([209.85.223.195]:34364 "EHLO mail-io0-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752268AbdGDKkf (ORCPT ); Tue, 4 Jul 2017 06:40:35 -0400 MIME-Version: 1.0 In-Reply-To: <1494751435-14189-1-git-send-email-der.herr@hofr.at> References: <1494751435-14189-1-git-send-email-der.herr@hofr.at> From: Geert Uytterhoeven Date: Tue, 4 Jul 2017 12:40:33 +0200 X-Google-Sender-Auth: cIgxKxRy18DzrXjCXPxQxgQrrJc Message-ID: Subject: Re: [PATCH RFC] iio: pressure: zpa2326: report interrupted case as failure To: Nicholas Mc Guire Cc: Jonathan Cameron , Hartmut Knaack , Lars-Peter Clausen , Peter Meerwald-Stadler , simran singhal , Arnd Bergmann , Gregor Boirie , linux-iio@vger.kernel.org, "linux-kernel@vger.kernel.org" Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: 8bit X-MIME-Autoconverted: from quoted-printable to 8bit by mail.home.local id v64AekHH010725 Content-Length: 3233 Lines: 89 Hi Nicholas, On Sun, May 14, 2017 at 10:43 AM, Nicholas Mc Guire 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 > --- > > 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