Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933580AbdCURrY (ORCPT ); Tue, 21 Mar 2017 13:47:24 -0400 Received: from mail-pg0-f65.google.com ([74.125.83.65]:33766 "EHLO mail-pg0-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757455AbdCURrT (ORCPT ); Tue, 21 Mar 2017 13:47:19 -0400 Date: Tue, 21 Mar 2017 10:47:06 -0700 From: Alison Schofield To: SIMRAN SINGHAL Cc: Lars-Peter Clausen , Michael Hennerich , Jonathan Cameron , Hartmut Knaack , Peter Meerwald-Stadler , Greg Kroah-Hartman , linux-iio@vger.kernel.org, devel@driverdev.osuosl.org, linux-kernel@vger.kernel.org, outreachy-kernel Subject: Re: [Outreachy kernel] [PATCH v6] staging: Use buf_lock instead of mlock and Refactor code Message-ID: <20170321174706.GE2793@d830.WORKGROUP> References: <20170319200621.GA21295@singhal-Inspiron-5558> <20170321164812.GA2793@d830.WORKGROUP> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 5960 Lines: 158 On Tue, Mar 21, 2017 at 10:34:01PM +0530, SIMRAN SINGHAL wrote: > On Tue, Mar 21, 2017 at 10:18 PM, Alison Schofield wrote: > > On Mon, Mar 20, 2017 at 01:36:21AM +0530, simran singhal wrote: > > > > Hi Simran, > > > > I going to ask for a v7 without looking at the code ;) > > Subject line needs subsystem and driver. > > Subject and log message can be improved. > > Hi Alison, > I have already sent v7 with changed subject. Simran, I see v7. Needs subsystem (iio) and to nitpick, driver name is "adis16060" ;) Other comments still apply. Please append all version histories below the --- for review. v7: v6: . . v2: thanks, alisons > > > > >> 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. > > ^^^^^^^^^^^ this was not done > >> > >> 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. > > This was done. So, you were able to obsolete the need for mlock > > by creating the paired function. > > > >> > >> Removed nested locks as the function adis16060_read_raw call > >> a lock on &st->buf_lock and then calls the function > >> adis16060_spi_write which again tries to get hold > >> of the same lock. > > ^^^^ this was not done. Yes, you avoided nested locks through > > proper coding, but we don't want to give the impression in the > > log message that there was a pre-existing nested lock issue. > > > > I did checkpatch & compile it...but looked no further yet. > > > > alisons > >> > >> Signed-off-by: simran singhal > >> --- > >> > >> v6: > >> -Change commit message > >> -Remove nested lock > >> > >> drivers/staging/iio/gyro/adis16060_core.c | 40 ++++++++++--------------------- > >> 1 file changed, 13 insertions(+), 27 deletions(-) > >> > >> diff --git a/drivers/staging/iio/gyro/adis16060_core.c b/drivers/staging/iio/gyro/adis16060_core.c > >> index c9d46e7..1c6de46 100644 > >> --- a/drivers/staging/iio/gyro/adis16060_core.c > >> +++ b/drivers/staging/iio/gyro/adis16060_core.c > >> @@ -40,25 +40,17 @@ 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 conf, u16 *val) > >> { > >> int ret; > >> struct adis16060_state *st = iio_priv(indio_dev); > >> > >> - mutex_lock(&st->buf_lock); > >> - st->buf[2] = val; /* The last 8 bits clocked in are latched */ > >> + st->buf[2] = conf; /* 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) > >> + return ret; > >> > >> ret = spi_read(st->us_r, st->buf, 3); > >> > >> @@ -69,8 +61,8 @@ static int adis16060_spi_read(struct iio_dev *indio_dev, u16 *val) > >> */ > >> if (!ret) > >> *val = ((st->buf[0] & 0x3) << 12) | > >> - (st->buf[1] << 4) | > >> - ((st->buf[2] >> 4) & 0xF); > >> + (st->buf[1] << 4) | > >> + ((st->buf[2] >> 4) & 0xF); > >> mutex_unlock(&st->buf_lock); > >> > >> return ret; > >> @@ -83,20 +75,18 @@ 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); > >> + mutex_unlock(&st->buf_lock); > >> if (ret < 0) > >> - goto out_unlock; > >> + return ret; > >> > >> - ret = adis16060_spi_read(indio_dev, &tval); > >> - if (ret < 0) > >> - goto out_unlock; > >> - > >> - mutex_unlock(&indio_dev->mlock); > >> *val = tval; > >> return IIO_VAL_INT; > >> case IIO_CHAN_INFO_OFFSET: > >> @@ -110,10 +100,6 @@ static int adis16060_read_raw(struct iio_dev *indio_dev, > >> } > >> > >> return -EINVAL; > >> - > >> -out_unlock: > >> - mutex_unlock(&indio_dev->mlock); > >> - return ret; > >> } > >> > >> static const struct iio_info adis16060_info = { > >> -- > >> 2.7.4 > >> > >> -- > >> You received this message because you are subscribed to the Google Groups "outreachy-kernel" group. > >> To unsubscribe from this group and stop receiving emails from it, send an email to outreachy-kernel+unsubscribe@googlegroups.com. > >> To post to this group, send email to outreachy-kernel@googlegroups.com. > >> To view this discussion on the web visit https://groups.google.com/d/msgid/outreachy-kernel/20170319200621.GA21295%40singhal-Inspiron-5558. > >> For more options, visit https://groups.google.com/d/optout.