Re: [Outreachy kernel] [PATCH v6] staging: Use buf_lock instead of mlock and Refactor code

[SIMRAN SINGHAL]

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.
>
>> 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.

I am still using mlock but now locking it and performing both write and
read and than unlocking.

So, now have a single safe function.

>
>>
>> Removed nested locks as the function adis16060_read_raw call
>> a lock on >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(>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(>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(>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(>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(_dev->mlock);
>> - ret = adis16060_spi_write(indio_dev, chan->address);
>> + mutex_lock(>buf_lock);
>> + ret = adis16060_spi_write_than_read(indio_dev,
>> + chan->address, );
>> + mutex_unlock(>buf_lock);
>>   if (ret < 0)
>> - goto out_unlock;
>> + return ret;
>>
>> - ret = adis16060_spi_read(indio_dev, );
>> - if (ret < 0)
>> - goto out_unlock;
>> -
>> - mutex_unlock(_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(_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 
>> 

Re: [Outreachy kernel] [PATCH v6] staging: Use buf_lock instead of mlock and Refactor code

[SIMRAN SINGHAL]

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.
>
>> 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.

I am still using mlock but now locking it and performing both write and
read and than unlocking.

So, now have a single safe function.

>
>>
>> Removed nested locks as the function adis16060_read_raw call
>> a lock on >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(>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(>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(>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(>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(_dev->mlock);
>> - ret = adis16060_spi_write(indio_dev, chan->address);
>> + mutex_lock(>buf_lock);
>> + ret = adis16060_spi_write_than_read(indio_dev,
>> + chan->address, );
>> + mutex_unlock(>buf_lock);
>>   if (ret < 0)
>> - goto out_unlock;
>> + return ret;
>>
>> - ret = adis16060_spi_read(indio_dev, );
>> - if (ret < 0)
>> - goto out_unlock;
>> -
>> - mutex_unlock(_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(_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 

Re: [Outreachy kernel] [PATCH v6] staging: Use buf_lock instead of mlock and Refactor code

[Alison Schofield]

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 >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(>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(>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(>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(>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(_dev->mlock);
> >> - ret = adis16060_spi_write(indio_dev, chan->address);
> >> + mutex_lock(>buf_lock);
> >> + ret = adis16060_spi_write_than_read(indio_dev,
> >> + chan->address, );
> >> + mutex_unlock(>buf_lock);
> >>   if (ret < 0)
> >> - goto out_unlock;
> >> + return ret;
> >>
> >> - ret = adis16060_spi_read(indio_dev, );
> >> - if (ret < 0)
> >> - goto out_unlock;
> >> -
> >> - mutex_unlock(_dev->mlock);
> >> 

Re: [Outreachy kernel] [PATCH v6] staging: Use buf_lock instead of mlock and Refactor code

[Alison Schofield]

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 >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(>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(>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(>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(>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(_dev->mlock);
> >> - ret = adis16060_spi_write(indio_dev, chan->address);
> >> + mutex_lock(>buf_lock);
> >> + ret = adis16060_spi_write_than_read(indio_dev,
> >> + chan->address, );
> >> + mutex_unlock(>buf_lock);
> >>   if (ret < 0)
> >> - goto out_unlock;
> >> + return ret;
> >>
> >> - ret = adis16060_spi_read(indio_dev, );
> >> - if (ret < 0)
> >> - goto out_unlock;
> >> -
> >> - mutex_unlock(_dev->mlock);
> >>   *val = tval;
> >>   return 

Re: [Outreachy kernel] [PATCH v6] staging: Use buf_lock instead of mlock and Refactor code

[SIMRAN SINGHAL]

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.

>
>> 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 >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(>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(>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(>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(>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(_dev->mlock);
>> - ret = adis16060_spi_write(indio_dev, chan->address);
>> + mutex_lock(>buf_lock);
>> + ret = adis16060_spi_write_than_read(indio_dev,
>> + chan->address, );
>> + mutex_unlock(>buf_lock);
>>   if (ret < 0)
>> - goto out_unlock;
>> + return ret;
>>
>> - ret = adis16060_spi_read(indio_dev, );
>> - if (ret < 0)
>> - goto out_unlock;
>> -
>> - mutex_unlock(_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(_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 

Re: [Outreachy kernel] [PATCH v6] staging: Use buf_lock instead of mlock and Refactor code

[SIMRAN SINGHAL]

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.

>
>> 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 >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(>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(>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(>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(>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(_dev->mlock);
>> - ret = adis16060_spi_write(indio_dev, chan->address);
>> + mutex_lock(>buf_lock);
>> + ret = adis16060_spi_write_than_read(indio_dev,
>> + chan->address, );
>> + mutex_unlock(>buf_lock);
>>   if (ret < 0)
>> - goto out_unlock;
>> + return ret;
>>
>> - ret = adis16060_spi_read(indio_dev, );
>> - if (ret < 0)
>> - goto out_unlock;
>> -
>> - mutex_unlock(_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(_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 

Re: [Outreachy kernel] [PATCH v6] staging: Use buf_lock instead of mlock and Refactor code

[Alison Schofield]

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.

> 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 >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(>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(>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(>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(>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(_dev->mlock);
> - ret = adis16060_spi_write(indio_dev, chan->address);
> + mutex_lock(>buf_lock);
> + ret = adis16060_spi_write_than_read(indio_dev,
> + chan->address, );
> + mutex_unlock(>buf_lock);
>   if (ret < 0)
> - goto out_unlock;
> + return ret;
>  
> - ret = adis16060_spi_read(indio_dev, );
> - if (ret < 0)
> - goto out_unlock;
> -
> - mutex_unlock(_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(_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+unsubscr...@googlegroups.com.
> To post to this group, send email to outreachy-ker...@googlegroups.com.
> To view this discussion on the web visit 
> 

Re: [Outreachy kernel] [PATCH v6] staging: Use buf_lock instead of mlock and Refactor code

[Alison Schofield]

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.

> 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 >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(>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(>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(>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(>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(_dev->mlock);
> - ret = adis16060_spi_write(indio_dev, chan->address);
> + mutex_lock(>buf_lock);
> + ret = adis16060_spi_write_than_read(indio_dev,
> + chan->address, );
> + mutex_unlock(>buf_lock);
>   if (ret < 0)
> - goto out_unlock;
> + return ret;
>  
> - ret = adis16060_spi_read(indio_dev, );
> - if (ret < 0)
> - goto out_unlock;
> -
> - mutex_unlock(_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(_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+unsubscr...@googlegroups.com.
> To post to this group, send email to outreachy-ker...@googlegroups.com.
> To view this discussion on the web visit 
>