From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751442AbdCSKQc (ORCPT ); Sun, 19 Mar 2017 06:16:32 -0400 Received: from saturn.retrosnub.co.uk ([178.18.118.26]:48196 "EHLO saturn.retrosnub.co.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751269AbdCSKQa (ORCPT ); Sun, 19 Mar 2017 06:16:30 -0400 Subject: Re: [PATCH v4] staging: Use buf_lock instead of mlock and Refactor code To: simran singhal , lars@metafoo.de References: <20170318184428.GA12858@singhal-Inspiron-5558> From: Jonathan Cameron Cc: Michael.Hennerich@analog.com, Hartmut Knaack , Peter Meerwald-Stadler , Greg Kroah-Hartman , linux-iio@vger.kernel.org, devel@driverdev.osuosl.org, linux-kernel@vger.kernel.org, outreachy-kernel@googlegroups.com Message-ID: <9d3c64ac-c7ae-fe6f-9afc-8cfd7931fb61@kernel.org> Date: Sun, 19 Mar 2017 10:15:56 +0000 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.8.0 MIME-Version: 1.0 In-Reply-To: <20170318184428.GA12858@singhal-Inspiron-5558> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 18/03/17 18:44, simran singhal wrote: > The IIO subsystem is redefining iio_dev->mlock to be used by > the IIO core only for protecting device operating mode changes. > ie. Changes between INDIO_DIRECT_MODE, INDIO_BUFFER_* modes. > > In this driver, mlock was being used to protect hardware state > changes. Replace it with buf_lock in the devices global data. > > As buf_lock protects both the adis16060_spi_write() and > adis16060_spi_read() functions and both are always called in > pair. First write, then read. Thus, refactor the code to have > one single function adis16060_spi_write_than_read() which is > protected by the existing buf_lock. > > Signed-off-by: simran singhal Hi Simran, A couple of minor comments and opportunity to further improve the, now simpler, code flow. Thanks, Jonathan > --- > > v4: > -Refactored code > -change commit subject > -change commit message > > drivers/staging/iio/gyro/adis16060_core.c | 37 ++++++++++++------------------- > 1 file changed, 14 insertions(+), 23 deletions(-) > > diff --git a/drivers/staging/iio/gyro/adis16060_core.c b/drivers/staging/iio/gyro/adis16060_core.c > index c9d46e7..39ddd55 100644 > --- a/drivers/staging/iio/gyro/adis16060_core.c > +++ b/drivers/staging/iio/gyro/adis16060_core.c > @@ -40,7 +40,7 @@ struct adis16060_state { > > static struct iio_dev *adis16060_iio_dev; > > -static int adis16060_spi_write(struct iio_dev *indio_dev, u8 val) > +static int adis16060_spi_write_than_read(struct iio_dev *indio_dev, u8 val, u16 *val2) val and val2 often have specific meanings in IIO. I'd prefer these to be renamed to val => conf (as it sets the configuration) and val2 => val. > { > int ret; > struct adis16060_state *st = iio_priv(indio_dev); > @@ -48,17 +48,11 @@ static int adis16060_spi_write(struct iio_dev *indio_dev, u8 val) > mutex_lock(&st->buf_lock); > st->buf[2] = val; /* The last 8 bits clocked in are latched */ > ret = spi_write(st->us_w, st->buf, 3); > - mutex_unlock(&st->buf_lock); > > - return ret; > -} > - > -static int adis16060_spi_read(struct iio_dev *indio_dev, u16 *val) > -{ > - int ret; > - struct adis16060_state *st = iio_priv(indio_dev); > - > - mutex_lock(&st->buf_lock); > + if (ret < 0) { > + mutex_unlock(&st->buf_lock); > + return ret; > + } > > ret = spi_read(st->us_r, st->buf, 3); > > @@ -67,10 +61,10 @@ static int adis16060_spi_read(struct iio_dev *indio_dev, u16 *val) > * starts to place data MSB first on the DOUT line at > * the 6th falling edge of SCLK > */ > - if (!ret) > - *val = ((st->buf[0] & 0x3) << 12) | > - (st->buf[1] << 4) | > - ((st->buf[2] >> 4) & 0xF); > + if (!ret) Please run checkpatch.pl over your patches. Looks like you ended up with spaces instead of a tab in the line above. > + *val2 = ((st->buf[0] & 0x3) << 12) | > + (st->buf[1] << 4) | > + ((st->buf[2] >> 4) & 0xF); > mutex_unlock(&st->buf_lock); > > return ret; > @@ -83,20 +77,17 @@ static int adis16060_read_raw(struct iio_dev *indio_dev, > { > u16 tval = 0; > int ret; > + struct adis16060_state *st = iio_priv(indio_dev); > > switch (mask) { > case IIO_CHAN_INFO_RAW: > /* Take the iio_dev status lock */ > - mutex_lock(&indio_dev->mlock); > - ret = adis16060_spi_write(indio_dev, chan->address); > + mutex_lock(&st->buf_lock); > + ret = adis16060_spi_write_than_read(indio_dev, chan->address, &tval); > if (ret < 0) > goto out_unlock; > > - ret = adis16060_spi_read(indio_dev, &tval); > - if (ret < 0) This ugly goto construction arguably made sense when there were two of them. Now you have only one just bring the mutex_unlock inline and return directly. > - goto out_unlock; > - > - mutex_unlock(&indio_dev->mlock); > + mutex_unlock(&st->buf_lock); > *val = tval; > return IIO_VAL_INT; > case IIO_CHAN_INFO_OFFSET: > @@ -112,7 +103,7 @@ static int adis16060_read_raw(struct iio_dev *indio_dev, > return -EINVAL; > > out_unlock: > - mutex_unlock(&indio_dev->mlock); > + mutex_unlock(&st->buf_lock); > return ret; > } > >