Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752448AbdGDTJA convert rfc822-to-8bit (ORCPT ); Tue, 4 Jul 2017 15:09:00 -0400 Received: from mail.kernel.org ([198.145.29.99]:56616 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752053AbdGDTI6 (ORCPT ); Tue, 4 Jul 2017 15:08:58 -0400 DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 257F022B54 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=jic23@kernel.org Date: Tue, 4 Jul 2017 20:08:53 +0100 From: Jonathan Cameron To: Geert Uytterhoeven Cc: Nicholas Mc Guire , Hartmut Knaack , Lars-Peter Clausen , Peter Meerwald-Stadler , simran singhal , Arnd Bergmann , Gregor Boirie , linux-iio@vger.kernel.org, "linux-kernel@vger.kernel.org" Subject: Re: [PATCH RFC] iio: pressure: zpa2326: report interrupted case as failure Message-ID: <20170704200853.16dc9e3a@kernel.org> In-Reply-To: References: <1494751435-14189-1-git-send-email-der.herr@hofr.at> X-Mailer: Claws Mail 3.15.0-dirty (GTK+ 2.24.31; x86_64-unknown-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3755 Lines: 99 On Tue, 4 Jul 2017 12:40:33 +0200 Geert Uytterhoeven wrote: > 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 Good analysis. Care to send the obvious patch? J > > 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 > -- > To unsubscribe from this list: send the line "unsubscribe linux-iio" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html