Received: by 2002:a25:8b91:0:0:0:0:0 with SMTP id j17csp3352006ybl; Sun, 15 Dec 2019 08:02:44 -0800 (PST) X-Google-Smtp-Source: APXvYqzIuK20FqXk1KFVhq9qaryFFg1KHNjQDRNyMn4ardoIgvvatVShoos+FU5QYNzG4rDvqiJC X-Received: by 2002:a9d:73c8:: with SMTP id m8mr27769415otk.34.1576425764729; Sun, 15 Dec 2019 08:02:44 -0800 (PST) ARC-Seal: i=1; a=rsa-sha256; t=1576425764; cv=none; d=google.com; s=arc-20160816; b=yRVQVFxR+AGdz88M9Ci5SQB6W/FYLkirTjSQrt1r0Rbb3dlSa/NhoDCOYXqgCgow5d 5+vOuVCkWstuqlm5rYLHzYv7PgvmvlkgmP2j4avHZnbTv/1a+X6r8Pav5rnHygolOetf c7Ph3o2wE/AsJBBukRVFBzoaCA7ZVfMDPOdYLG4UzMdnB7DIZSRVG42wvHyZfrh5odwM iQdU66C2zGV+qF6Ob4hCqCwHUoSrOf/n6/gHcl3bwZCD9sXSlNbXhti5S999B4jzTvg2 68CrdNO0W2h6XumBHuGF9jNn9NU39TAYqft2cpShBeNaPtqKMOlvJ34HFDTYnqmiTs10 iTYA== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:sender:content-transfer-encoding:mime-version :references:in-reply-to:message-id:subject:cc:to:from:date; bh=45uEdhoudfa2S4uxasEYd85QBSg92DktBrbGqRy0IMU=; b=fsvoPoeMo4xfE5g6HDfJeGOUaPTcjJarsTojsoQqoy9WJdOVmsfRRSxewAXW2RchGv k+Ay+Ph06BBLM7xEE8+8O/1tPcF3oCb51+aB4f66rlsuxYJOT6k3uAwj82GuNpGk4Gbm lUZIRDiEtSQIDQkPepvsogBVIVS+zsAapOL5I1iu6MBgMx3oPzgIrtQ1nuDMtkE6sgnI IzNXdp+BXa8T6RX66rFYY6acTLnIeRrv9iAVVqWNIqiU5F3JNd67sP9QS3zecHVNKiVP xHp/6zsj4SzW68fOlzZJmHdc89GbrC2F67qzFnPGmkqpNWkER+6BtKjTvGwCVksxueGO PkUg== ARC-Authentication-Results: i=1; mx.google.com; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Return-Path: Received: from vger.kernel.org (vger.kernel.org. [209.132.180.67]) by mx.google.com with ESMTP id x207si8590827oif.30.2019.12.15.08.02.33; Sun, 15 Dec 2019 08:02:44 -0800 (PST) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726818AbfLOQB2 (ORCPT + 99 others); Sun, 15 Dec 2019 11:01:28 -0500 Received: from saturn.retrosnub.co.uk ([46.235.226.198]:44502 "EHLO saturn.retrosnub.co.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726481AbfLOQBU (ORCPT ); Sun, 15 Dec 2019 11:01:20 -0500 Received: from archlinux (cpc149474-cmbg20-2-0-cust94.5-4.cable.virginm.net [82.4.196.95]) by saturn.retrosnub.co.uk (Postfix; Retrosnub mail submission) with ESMTPSA id B7B3B9E76A6; Sun, 15 Dec 2019 15:55:08 +0000 (GMT) Date: Sun, 15 Dec 2019 15:55:07 +0000 From: Jonathan Cameron To: Sasha Levin Cc: linux-kernel@vger.kernel.org, stable@vger.kernel.org, Alexandru Ardelean , Jonathan Cameron , linux-iio@vger.kernel.org Subject: Re: [PATCH AUTOSEL 5.4 117/350] iio: dac: ad7303: replace mlock with own lock Message-ID: <20191215155507.08026268@archlinux> In-Reply-To: <20191210210735.9077-78-sashal@kernel.org> References: <20191210210735.9077-1-sashal@kernel.org> <20191210210735.9077-78-sashal@kernel.org> X-Mailer: Claws Mail 3.17.4 (GTK+ 2.24.32; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 10 Dec 2019 16:03:42 -0500 Sasha Levin wrote: > From: Alexandru Ardelean > > [ Upstream commit c991bf9b650f39481cf3c1137092d4754a2c75de ] > > This change replaces indio_dev's mlock with the driver's own lock. The lock > is mostly needed to protect state when changing the `dac_cache` info. > The lock has been extended to `ad7303_read_raw()`, to make sure that the > cache is updated if an SPI-write is already in progress. This is not a fix. It's undoing some slightly nasty layer violations that we are trying to drive out of IIO, but as far as I know there is no actual bug with what was there before. I won't do any harm though other than adding noise. Jonathan > > Signed-off-by: Alexandru Ardelean > Signed-off-by: Jonathan Cameron > Signed-off-by: Sasha Levin > --- > drivers/iio/dac/ad7303.c | 13 +++++++++---- > 1 file changed, 9 insertions(+), 4 deletions(-) > > diff --git a/drivers/iio/dac/ad7303.c b/drivers/iio/dac/ad7303.c > index 8de9f40226e62..14bbac6bee982 100644 > --- a/drivers/iio/dac/ad7303.c > +++ b/drivers/iio/dac/ad7303.c > @@ -41,6 +41,7 @@ struct ad7303_state { > struct regulator *vdd_reg; > struct regulator *vref_reg; > > + struct mutex lock; > /* > * DMA (thus cache coherency maintenance) requires the > * transfer buffers to live in their own cache lines. > @@ -79,7 +80,7 @@ static ssize_t ad7303_write_dac_powerdown(struct iio_dev *indio_dev, > if (ret) > return ret; > > - mutex_lock(&indio_dev->mlock); > + mutex_lock(&st->lock); > > if (pwr_down) > st->config |= AD7303_CFG_POWER_DOWN(chan->channel); > @@ -90,7 +91,7 @@ static ssize_t ad7303_write_dac_powerdown(struct iio_dev *indio_dev, > * mode, so just write one of the DAC channels again */ > ad7303_write(st, chan->channel, st->dac_cache[chan->channel]); > > - mutex_unlock(&indio_dev->mlock); > + mutex_unlock(&st->lock); > return len; > } > > @@ -116,7 +117,9 @@ static int ad7303_read_raw(struct iio_dev *indio_dev, > > switch (info) { > case IIO_CHAN_INFO_RAW: > + mutex_lock(&st->lock); > *val = st->dac_cache[chan->channel]; > + mutex_unlock(&st->lock); > return IIO_VAL_INT; > case IIO_CHAN_INFO_SCALE: > vref_uv = ad7303_get_vref(st, chan); > @@ -144,11 +147,11 @@ static int ad7303_write_raw(struct iio_dev *indio_dev, > if (val >= (1 << chan->scan_type.realbits) || val < 0) > return -EINVAL; > > - mutex_lock(&indio_dev->mlock); > + mutex_lock(&st->lock); > ret = ad7303_write(st, chan->address, val); > if (ret == 0) > st->dac_cache[chan->channel] = val; > - mutex_unlock(&indio_dev->mlock); > + mutex_unlock(&st->lock); > break; > default: > ret = -EINVAL; > @@ -211,6 +214,8 @@ static int ad7303_probe(struct spi_device *spi) > > st->spi = spi; > > + mutex_init(&st->lock); > + > st->vdd_reg = devm_regulator_get(&spi->dev, "Vdd"); > if (IS_ERR(st->vdd_reg)) > return PTR_ERR(st->vdd_reg);