[PATCH v8] staging: adis16060: Remove iio_dev mlock and refactor code

[PATCH v8] staging: adis16060: Remove iio_dev mlock and refactor code

[simran singhal]

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.

In the driver, buf_lock protects both the adis16060_spi_write() and
adis16060_spi_read() functions and both are always called in
pair. First write, then read. Refactor the code to have
one single function adis16060_spi_write_than_read() and remove
the use of mlock as adis16060_read_raw() does not require an
iio_dev->mlock for reads.

Signed-off-by: simran singhal <singhalsimran0@gmail.com>
---

 v8:
   -change subject
   -change commit message
 v7:
   -Change subject
   -Remove lock from read_raw instead from
    function adis16060_spi_write_than_read().
 v6:
   -Change commit message
   -Remove nested lock
 v5:
   -Rename val in adis16060_spi_write_than_read() to conf.
   -Rename val2 in adis16060_spi_write_than_read() to val.
   -Corrected Checkpatch issues.
   -Removed goto from adis16060_read_raw().
 v4:
   -Refactored code
   -change commit subject
   -change commit message
 v3:
   -Removed new lock to reuse the existing lock
 v2:
   -Fixed compilation error

 drivers/staging/iio/gyro/adis16060_core.c | 33 ++++++++-----------------------
 1 file changed, 8 insertions(+), 25 deletions(-)

diff --git a/drivers/staging/iio/gyro/adis16060_core.c b/drivers/staging/iio/gyro/adis16060_core.c
index c9d46e7..e96fce5 100644
--- a/drivers/staging/iio/gyro/adis16060_core.c
+++ b/drivers/staging/iio/gyro/adis16060_core.c
@@ -40,25 +40,18 @@ 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);
 
@@ -86,17 +79,11 @@ static int adis16060_read_raw(struct iio_dev *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);
+		ret = adis16060_spi_write_than_read(indio_dev,
+						    chan->address, &tval);
 		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 +97,6 @@ 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

Re: [PATCH v8] staging: adis16060: Remove iio_dev mlock and refactor code

[Jonathan Cameron]

On 22/03/17 16:20, 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.
> 
> In the driver, buf_lock protects both the adis16060_spi_write() and
> adis16060_spi_read() functions and both are always called in
> pair. First write, then read. Refactor the code to have
> one single function adis16060_spi_write_than_read() and remove
> the use of mlock as adis16060_read_raw() does not require an
> iio_dev->mlock for reads.
I'll slightly modify this description.  The key thing is
that after the above change to have a unified read then write
there is no longer any need for mlock to protect these
read, update, write cycles.
> 
> Signed-off-by: simran singhal <singhalsimran0@gmail.com>
Applied to the togreg branch of iio.git and pushed out as testing
for the autobuilders to play with it.

I slightly modified the title as well. It's useful to be a little
more specific than staging, so I added iio: after that.

Thanks,

Jonathan
> ---
> 
>  v8:
>    -change subject
>    -change commit message
>  v7:
>    -Change subject
>    -Remove lock from read_raw instead from
>     function adis16060_spi_write_than_read().
>  v6:
>    -Change commit message
>    -Remove nested lock
>  v5:
>    -Rename val in adis16060_spi_write_than_read() to conf.
>    -Rename val2 in adis16060_spi_write_than_read() to val.
>    -Corrected Checkpatch issues.
>    -Removed goto from adis16060_read_raw().
>  v4:
>    -Refactored code
>    -change commit subject
>    -change commit message
>  v3:
>    -Removed new lock to reuse the existing lock
>  v2:
>    -Fixed compilation error
> 
>  drivers/staging/iio/gyro/adis16060_core.c | 33 ++++++++-----------------------
>  1 file changed, 8 insertions(+), 25 deletions(-)
> 
> diff --git a/drivers/staging/iio/gyro/adis16060_core.c b/drivers/staging/iio/gyro/adis16060_core.c
> index c9d46e7..e96fce5 100644
> --- a/drivers/staging/iio/gyro/adis16060_core.c
> +++ b/drivers/staging/iio/gyro/adis16060_core.c
> @@ -40,25 +40,18 @@ 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);
>  
> @@ -86,17 +79,11 @@ static int adis16060_read_raw(struct iio_dev *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);
> +		ret = adis16060_spi_write_than_read(indio_dev,
> +						    chan->address, &tval);
>  		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 +97,6 @@ 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 = {
> 

Re: [PATCH v8] staging: adis16060: Remove iio_dev mlock and refactor code

[Jonathan Cameron]

On 22 March 2017 19:22:20 GMT+00:00, Jonathan Cameron <jic23@kernel.org> wrote:
>On 22/03/17 16:20, 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.
>> 
>> In the driver, buf_lock protects both the adis16060_spi_write() and
>> adis16060_spi_read() functions and both are always called in
>> pair. First write, then read. Refactor the code to have
>> one single function adis16060_spi_write_than_read() and remove
>> the use of mlock as adis16060_read_raw() does not require an
>> iio_dev->mlock for reads.
>I'll slightly modify this description.  The key thing is
>that after the above change to have a unified read then write
>there is no longer any need for mlock to protect these
>read, update, write cycles.
>> 
>> Signed-off-by: simran singhal <singhalsimran0@gmail.com>
>Applied to the togreg branch of iio.git and pushed out as testing
>for the autobuilders to play with it.
>
>I slightly modified the title as well. It's useful to be a little
>more specific than staging, so I added iio: after that.

Another example of how the tests that 0day is doing are way better than my tired eyes at the end of a day...
>
>Thanks,
>
>Jonathan
>> ---
>> 
>>  v8:
>>    -change subject
>>    -change commit message
>>  v7:
>>    -Change subject
>>    -Remove lock from read_raw instead from
>>     function adis16060_spi_write_than_read().
>>  v6:
>>    -Change commit message
>>    -Remove nested lock
>>  v5:
>>    -Rename val in adis16060_spi_write_than_read() to conf.
>>    -Rename val2 in adis16060_spi_write_than_read() to val.
>>    -Corrected Checkpatch issues.
>>    -Removed goto from adis16060_read_raw().
>>  v4:
>>    -Refactored code
>>    -change commit subject
>>    -change commit message
>>  v3:
>>    -Removed new lock to reuse the existing lock
>>  v2:
>>    -Fixed compilation error
>> 
>>  drivers/staging/iio/gyro/adis16060_core.c | 33
>++++++++-----------------------
>>  1 file changed, 8 insertions(+), 25 deletions(-)
>> 
>> diff --git a/drivers/staging/iio/gyro/adis16060_core.c
>b/drivers/staging/iio/gyro/adis16060_core.c
>> index c9d46e7..e96fce5 100644
>> --- a/drivers/staging/iio/gyro/adis16060_core.c
>> +++ b/drivers/staging/iio/gyro/adis16060_core.c
>> @@ -40,25 +40,18 @@ 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)
Not unlocking buf_lock in this path.  I will fix up later....

Jonathan
>> +		return ret;
>>  
>>  	ret = spi_read(st->us_r, st->buf, 3);
>>  
>> @@ -86,17 +79,11 @@ static int adis16060_read_raw(struct iio_dev
>*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);
>> +		ret = adis16060_spi_write_than_read(indio_dev,
>> +						    chan->address, &tval);
>>  		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 +97,6 @@ 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 = {
>> 
>
>--
>To unsubscribe from this list: send the line "unsubscribe linux-iio" in
>the body of a message to majordomo@vger.kernel.org
>More majordomo info at  http://vger.kernel.org/majordomo-info.html

-- 
Sent from my Android device with K-9 Mail. Please excuse my brevity.