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[89.64.59.159]) by smtp.gmail.com with ESMTPSA id a23sm152212ljd.20.2019.03.09.08.30.00 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Sat, 09 Mar 2019 08:30:00 -0800 (PST) Date: Sat, 9 Mar 2019 17:29:36 +0100 From: Tomasz Duszynski To: justinpopo6@gmail.com Cc: linux-iio@vger.kernel.org, linux-gpio@vger.kernel.org, bcm-kernel-feedback-list@broadcom.com, f.fainelli@gmail.com, bgolaszewski@baylibre.com, linus.walleij@linaro.org, jic23@kernel.org, knaack.h@gmx.de, lars@metafoo.de, pmeerw@pmeerw.net, linux-kernel@vger.kernel.org Subject: Re: [PATCH v5 1/2] iio: adc: ti-ads7950: Fix improper use of mlock Message-ID: <20190309162935.GC7820@arch> References: <1552082608-42603-1-git-send-email-justinpopo6@gmail.com> <1552082608-42603-2-git-send-email-justinpopo6@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <1552082608-42603-2-git-send-email-justinpopo6@gmail.com> User-Agent: Mutt/1.11.3 (2019-02-01) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Mar 08, 2019 at 02:03:27PM -0800, justinpopo6@gmail.com wrote: > From: Justin Chen > > Indio->mlock is used for protecting the different iio device modes. > It is currently not being used in this way. Replace the lock with > an internal lock specifically used for protecting the SPI transfer > buffer. > > Signed-off-by: Justin Chen > --- > drivers/iio/adc/ti-ads7950.c | 19 +++++++++++++++---- > 1 file changed, 15 insertions(+), 4 deletions(-) > > diff --git a/drivers/iio/adc/ti-ads7950.c b/drivers/iio/adc/ti-ads7950.c > index 0ad6359..1e47bef 100644 > --- a/drivers/iio/adc/ti-ads7950.c > +++ b/drivers/iio/adc/ti-ads7950.c > @@ -56,6 +56,9 @@ struct ti_ads7950_state { > struct spi_message ring_msg; > struct spi_message scan_single_msg; > > + /* Lock to protect the spi xfer buffers */ > + struct mutex slock; > + > struct regulator *reg; > unsigned int vref_mv; > > @@ -268,6 +271,7 @@ static irqreturn_t ti_ads7950_trigger_handler(int irq, void *p) > struct ti_ads7950_state *st = iio_priv(indio_dev); > int ret; > > + mutex_lock(&st->slock); > ret = spi_sync(st->spi, &st->ring_msg); > if (ret < 0) > goto out; > @@ -276,6 +280,7 @@ static irqreturn_t ti_ads7950_trigger_handler(int irq, void *p) > iio_get_time_ns(indio_dev)); > > out: > + mutex_unlock(&st->slock); > iio_trigger_notify_done(indio_dev->trig); > > return IRQ_HANDLED; > @@ -286,7 +291,7 @@ static int ti_ads7950_scan_direct(struct iio_dev *indio_dev, unsigned int ch) > struct ti_ads7950_state *st = iio_priv(indio_dev); > int ret, cmd; > > - mutex_lock(&indio_dev->mlock); > + mutex_lock(&st->slock); > > cmd = TI_ADS7950_CR_WRITE | TI_ADS7950_CR_CHAN(ch) | st->settings; > st->single_tx = cmd; > @@ -298,7 +303,7 @@ static int ti_ads7950_scan_direct(struct iio_dev *indio_dev, unsigned int ch) > ret = st->single_rx; > > out: > - mutex_unlock(&indio_dev->mlock); > + mutex_unlock(&st->slock); > > return ret; > } > @@ -432,16 +437,19 @@ static int ti_ads7950_probe(struct spi_device *spi) > if (ACPI_COMPANION(&spi->dev)) > st->vref_mv = TI_ADS7950_VA_MV_ACPI_DEFAULT; > > + mutex_init(&st->slock); > + > st->reg = devm_regulator_get(&spi->dev, "vref"); > if (IS_ERR(st->reg)) { > dev_err(&spi->dev, "Failed get get regulator \"vref\"\n"); > - return PTR_ERR(st->reg); > + ret = PTR_ERR(st->reg); > + goto error_destroy_mutex; > } > > ret = regulator_enable(st->reg); > if (ret) { > dev_err(&spi->dev, "Failed to enable regulator \"vref\"\n"); > - return ret; > + goto error_destroy_mutex; > } > > ret = iio_triggered_buffer_setup(indio_dev, NULL, > @@ -463,6 +471,8 @@ static int ti_ads7950_probe(struct spi_device *spi) > iio_triggered_buffer_cleanup(indio_dev); > error_disable_reg: > regulator_disable(st->reg); > +error_destroy_mutex: > + mutex_destroy(&st->slock); If your intention was to do resources cleanup then this is not what this api was designed for. This is actually for debugging unwanted subsequent mutex usage. > > return ret; > } > @@ -475,6 +485,7 @@ static int ti_ads7950_remove(struct spi_device *spi) > iio_device_unregister(indio_dev); > iio_triggered_buffer_cleanup(indio_dev); > regulator_disable(st->reg); > + mutex_destroy(&st->slock); > > return 0; > } > -- > 2.7.4 >