From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-14.6 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_2 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 49F6AC433E2 for ; Thu, 17 Sep 2020 18:43:02 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C6CA221D7B for ; Thu, 17 Sep 2020 18:43:01 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1600368181; bh=CdigQ/+3mxrVUS6hZ+1nUMXkX34CWxjHp9qYy4kPe2g=; h=Date:From:To:Cc:Subject:In-Reply-To:References:List-ID:From; b=AiCE8rz9Tfv0ixVVpjq1G5Rcm7KdL+hb+PKEDFSwsBUe/u3QNmaXZa8EPmOZXbYaV 2NdUb48B7EhghBl3hcIfNfSiKhnpY57bMSS5ZadrTyXWmzIGJIXQrVe7Wzqd+y7CjS DFhxZtiQ+HdpR4v3Z9u3W+CXNlWszB2Uceq3BWZc= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726412AbgIQSm6 (ORCPT ); Thu, 17 Sep 2020 14:42:58 -0400 Received: from mail.kernel.org ([198.145.29.99]:46450 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725882AbgIQSmi (ORCPT ); Thu, 17 Sep 2020 14:42:38 -0400 Received: from archlinux (cpc149474-cmbg20-2-0-cust94.5-4.cable.virginm.net [82.4.196.95]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id DF69721D7B; Thu, 17 Sep 2020 18:42:36 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1600368157; bh=CdigQ/+3mxrVUS6hZ+1nUMXkX34CWxjHp9qYy4kPe2g=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=Yvxz1yVf9HlZKzaI5XZkJ0swb7TQ4GqZr5VoHlNGY1vEsoFTw8PnkUhgufYWgD8jz ZI+i1i20lHPi6Tz7A5APBnNcSVHKL+tK688hMge35fRAhUtLSodp4abWRjClpBk758 o++88nfw29MtbOExF3szyxHr+yM8CzlSS/vZR+u8= Date: Thu, 17 Sep 2020 19:42:33 +0100 From: Jonathan Cameron To: Alexandru Ardelean Cc: , Subject: Re: [PATCH 3/3] iio: dac: ad5592r: localize locks only where needed in ad5592r_read_raw() Message-ID: <20200917194233.57b548be@archlinux> In-Reply-To: <20200706110259.23947-3-alexandru.ardelean@analog.com> References: <20200706110259.23947-1-alexandru.ardelean@analog.com> <20200706110259.23947-3-alexandru.ardelean@analog.com> X-Mailer: Claws Mail 3.17.6 (GTK+ 2.24.32; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 6 Jul 2020 14:02:59 +0300 Alexandru Ardelean wrote: > Since there was a recently discovered issue with these locks, it probably > makes sense to cleanup the code a bit, to prevent it from being used as an > example/reference. > > This change moves the lock only where it is explicitly needed to protect > resources from potential concurrent accesses. > > It also reworks the switch statements to do direct returns vs caching the > return value on a variable. > > Signed-off-by: Alexandru Ardelean Applied these two to the togreg branch of iio.git Thanks, Jonathan > --- > drivers/iio/dac/ad5592r-base.c | 30 +++++++++++++++--------------- > 1 file changed, 15 insertions(+), 15 deletions(-) > > diff --git a/drivers/iio/dac/ad5592r-base.c b/drivers/iio/dac/ad5592r-base.c > index 7ea79e9bfa1d..f697b20efb6e 100644 > --- a/drivers/iio/dac/ad5592r-base.c > +++ b/drivers/iio/dac/ad5592r-base.c > @@ -380,32 +380,32 @@ static int ad5592r_read_raw(struct iio_dev *iio_dev, > > switch (m) { > case IIO_CHAN_INFO_RAW: > - mutex_lock(&st->lock); > - > if (!chan->output) { > + mutex_lock(&st->lock); > ret = st->ops->read_adc(st, chan->channel, &read_val); > + mutex_unlock(&st->lock); > if (ret) > - goto unlock; > + return ret; > > if ((read_val >> 12 & 0x7) != (chan->channel & 0x7)) { > dev_err(st->dev, "Error while reading channel %u\n", > chan->channel); > - ret = -EIO; > - goto unlock; > + return -EIO; > } > > read_val &= GENMASK(11, 0); > > } else { > + mutex_lock(&st->lock); > read_val = st->cached_dac[chan->channel]; > + mutex_unlock(&st->lock); > } > > dev_dbg(st->dev, "Channel %u read: 0x%04hX\n", > chan->channel, read_val); > > *val = (int) read_val; > - ret = IIO_VAL_INT; > - break; > + return IIO_VAL_INT; > case IIO_CHAN_INFO_SCALE: > *val = ad5592r_get_vref(st); > > @@ -425,11 +425,13 @@ static int ad5592r_read_raw(struct iio_dev *iio_dev, > mult = !!(st->cached_gp_ctrl & > AD5592R_REG_CTRL_ADC_RANGE); > > + mutex_unlock(&st->lock); > + > *val *= ++mult; > > *val2 = chan->scan_type.realbits; > - ret = IIO_VAL_FRACTIONAL_LOG2; > - break; > + > + return IIO_VAL_FRACTIONAL_LOG2; > case IIO_CHAN_INFO_OFFSET: > ret = ad5592r_get_vref(st); > > @@ -439,15 +441,13 @@ static int ad5592r_read_raw(struct iio_dev *iio_dev, > *val = (-34365 * 25) / ret; > else > *val = (-75365 * 25) / ret; > - ret = IIO_VAL_INT; > - break; > + > + mutex_unlock(&st->lock); > + > + return IIO_VAL_INT; > default: > return -EINVAL; > } > - > -unlock: > - mutex_unlock(&st->lock); > - return ret; > } > > static int ad5592r_write_raw_get_fmt(struct iio_dev *indio_dev,