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Groups > linux.kernel > #1598623 > unrolled thread

[PATCH] staging: iio: ade7753: replace mlock with driver private lock

Started bysimran singhal <singhalsimran0@gmail.com>
First post2017-03-12 14:40 +0100
Last post2017-03-13 15:10 +0100
Articles 7 — 4 participants

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  [PATCH] staging: iio: ade7753: replace mlock with driver private lock simran singhal <singhalsimran0@gmail.com> - 2017-03-12 14:40 +0100
    Re: [Outreachy kernel] [PATCH] staging: iio: ade7753: replace mlock  with driver private lock Alison Schofield <amsfield22@gmail.com> - 2017-03-12 19:40 +0100
      Re: [Outreachy kernel] [PATCH] staging: iio: ade7753: replace mlock  with driver private lock SIMRAN SINGHAL <singhalsimran0@gmail.com> - 2017-03-13 05:00 +0100
        Re: [Outreachy kernel] [PATCH] staging: iio: ade7753: replace mlock  with driver private lock Alison Schofield <amsfield22@gmail.com> - 2017-03-13 06:40 +0100
    Re: [PATCH] staging: iio: ade7753: replace mlock with driver private  lock Lars-Peter Clausen <lars@metafoo.de> - 2017-03-13 13:10 +0100
      Re: [PATCH] staging: iio: ade7753: replace mlock with driver private lock SIMRAN SINGHAL <singhalsimran0@gmail.com> - 2017-03-13 13:40 +0100
        Re: [PATCH] staging: iio: ade7753: replace mlock with driver private  lock Lars-Peter Clausen <lars@metafoo.de> - 2017-03-13 15:10 +0100

#1598623 — [PATCH] staging: iio: ade7753: replace mlock with driver private lock

Fromsimran singhal <singhalsimran0@gmail.com>
Date2017-03-12 14:40 +0100
Subject[PATCH] staging: iio: ade7753: replace mlock with driver private lock
Message-ID<tkbT4-294-31@gated-at.bofh.it>
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 a lock in the devices global data.

Fix some coding style issues related to white space also.

Signed-off-by: simran singhal <singhalsimran0@gmail.com>
---
 drivers/staging/iio/meter/ade7753.c | 14 ++++++++------
 1 file changed, 8 insertions(+), 6 deletions(-)

diff --git a/drivers/staging/iio/meter/ade7753.c b/drivers/staging/iio/meter/ade7753.c
index dfd8b71..ca99d82 100644
--- a/drivers/staging/iio/meter/ade7753.c
+++ b/drivers/staging/iio/meter/ade7753.c
@@ -81,12 +81,14 @@
  * @tx:         transmit buffer
  * @rx:         receive buffer
  * @buf_lock:       mutex to protect tx and rx
+ * @lock:	protect sensor state
  **/
 struct ade7753_state {
-	    struct spi_device   *us;
-		    struct mutex        buf_lock;
-			    u8          tx[ADE7753_MAX_TX] ____cacheline_aligned;
-				    u8          rx[ADE7753_MAX_RX];
+	struct spi_device   *us;
+	struct mutex        buf_lock;
+	struct mutex        lock;	/* protect sensor state */
+	u8          tx[ADE7753_MAX_TX] ____cacheline_aligned;
+	u8          rx[ADE7753_MAX_RX];
 };
 
 static int ade7753_spi_write_reg_8(struct device *dev,
@@ -484,7 +486,7 @@ static ssize_t ade7753_write_frequency(struct device *dev,
 	if (!val)
 		return -EINVAL;
 
-	mutex_lock(&indio_dev->mlock);
+	mutex_lock(&st->lock);
 
 	t = 27900 / val;
 	if (t > 0)
@@ -505,7 +507,7 @@ static ssize_t ade7753_write_frequency(struct device *dev,
 	ret = ade7753_spi_write_reg_16(dev, ADE7753_MODE, reg);
 
 out:
-	mutex_unlock(&indio_dev->mlock);
+	mutex_unlock(&st->lock);
 
 	return ret ? ret : len;
 }
-- 
2.7.4

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#1598710 — Re: [Outreachy kernel] [PATCH] staging: iio: ade7753: replace mlock with driver private lock

FromAlison Schofield <amsfield22@gmail.com>
Date2017-03-12 19:40 +0100
SubjectRe: [Outreachy kernel] [PATCH] staging: iio: ade7753: replace mlock with driver private lock
Message-ID<tkgzo-5ml-11@gated-at.bofh.it>
In reply to#1598623
On Sun, Mar 12, 2017 at 07:02:50PM +0530, 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 a lock in the devices global data.
> 
> Fix some coding style issues related to white space also.
> 
> Signed-off-by: simran singhal <singhalsimran0@gmail.com>

Hi Simran, This looks good to me.  Let's see what the
reviewers say.  I think the white space stuff is ok,
since it was right where you were editing. 
alisons

> ---
>  drivers/staging/iio/meter/ade7753.c | 14 ++++++++------
>  1 file changed, 8 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/staging/iio/meter/ade7753.c b/drivers/staging/iio/meter/ade7753.c
> index dfd8b71..ca99d82 100644
> --- a/drivers/staging/iio/meter/ade7753.c
> +++ b/drivers/staging/iio/meter/ade7753.c
> @@ -81,12 +81,14 @@
>   * @tx:         transmit buffer
>   * @rx:         receive buffer
>   * @buf_lock:       mutex to protect tx and rx
> + * @lock:	protect sensor state
>   **/
>  struct ade7753_state {
> -	    struct spi_device   *us;
> -		    struct mutex        buf_lock;
> -			    u8          tx[ADE7753_MAX_TX] ____cacheline_aligned;
> -				    u8          rx[ADE7753_MAX_RX];
> +	struct spi_device   *us;
> +	struct mutex        buf_lock;
> +	struct mutex        lock;	/* protect sensor state */
> +	u8          tx[ADE7753_MAX_TX] ____cacheline_aligned;
> +	u8          rx[ADE7753_MAX_RX];
>  };
>  
>  static int ade7753_spi_write_reg_8(struct device *dev,
> @@ -484,7 +486,7 @@ static ssize_t ade7753_write_frequency(struct device *dev,
>  	if (!val)
>  		return -EINVAL;
>  
> -	mutex_lock(&indio_dev->mlock);
> +	mutex_lock(&st->lock);
>  
>  	t = 27900 / val;
>  	if (t > 0)
> @@ -505,7 +507,7 @@ static ssize_t ade7753_write_frequency(struct device *dev,
>  	ret = ade7753_spi_write_reg_16(dev, ADE7753_MODE, reg);
>  
>  out:
> -	mutex_unlock(&indio_dev->mlock);
> +	mutex_unlock(&st->lock);
>  
>  	return ret ? ret : len;
>  }
> -- 
> 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/20170312133250.GA7772%40singhal-Inspiron-5558.
> For more options, visit https://groups.google.com/d/optout.

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#1598840 — Re: [Outreachy kernel] [PATCH] staging: iio: ade7753: replace mlock with driver private lock

FromSIMRAN SINGHAL <singhalsimran0@gmail.com>
Date2017-03-13 05:00 +0100
SubjectRe: [Outreachy kernel] [PATCH] staging: iio: ade7753: replace mlock with driver private lock
Message-ID<tkpjk-2RV-3@gated-at.bofh.it>
In reply to#1598710
On Mon, Mar 13, 2017 at 12:03 AM, Alison Schofield <amsfield22@gmail.com> wrote:
> On Sun, Mar 12, 2017 at 07:02:50PM +0530, 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 a lock in the devices global data.
>>
>> Fix some coding style issues related to white space also.
>>
>> Signed-off-by: simran singhal <singhalsimran0@gmail.com>
>
> Hi Simran, This looks good to me.  Let's see what the
> reviewers say.  I think the white space stuff is ok,
> since it was right where you were editing.
> alisons
>
Alison, so sending this patch here on outreachy mailing list is fine.
Still confuse :P

>> ---
>>  drivers/staging/iio/meter/ade7753.c | 14 ++++++++------
>>  1 file changed, 8 insertions(+), 6 deletions(-)
>>
>> diff --git a/drivers/staging/iio/meter/ade7753.c b/drivers/staging/iio/meter/ade7753.c
>> index dfd8b71..ca99d82 100644
>> --- a/drivers/staging/iio/meter/ade7753.c
>> +++ b/drivers/staging/iio/meter/ade7753.c
>> @@ -81,12 +81,14 @@
>>   * @tx:         transmit buffer
>>   * @rx:         receive buffer
>>   * @buf_lock:       mutex to protect tx and rx
>> + * @lock:    protect sensor state
>>   **/
>>  struct ade7753_state {
>> -         struct spi_device   *us;
>> -                 struct mutex        buf_lock;
>> -                         u8          tx[ADE7753_MAX_TX] ____cacheline_aligned;
>> -                                 u8          rx[ADE7753_MAX_RX];
>> +     struct spi_device   *us;
>> +     struct mutex        buf_lock;
>> +     struct mutex        lock;       /* protect sensor state */
>> +     u8          tx[ADE7753_MAX_TX] ____cacheline_aligned;
>> +     u8          rx[ADE7753_MAX_RX];
>>  };
>>
>>  static int ade7753_spi_write_reg_8(struct device *dev,
>> @@ -484,7 +486,7 @@ static ssize_t ade7753_write_frequency(struct device *dev,
>>       if (!val)
>>               return -EINVAL;
>>
>> -     mutex_lock(&indio_dev->mlock);
>> +     mutex_lock(&st->lock);
>>
>>       t = 27900 / val;
>>       if (t > 0)
>> @@ -505,7 +507,7 @@ static ssize_t ade7753_write_frequency(struct device *dev,
>>       ret = ade7753_spi_write_reg_16(dev, ADE7753_MODE, reg);
>>
>>  out:
>> -     mutex_unlock(&indio_dev->mlock);
>> +     mutex_unlock(&st->lock);
>>
>>       return ret ? ret : len;
>>  }
>> --
>> 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/20170312133250.GA7772%40singhal-Inspiron-5558.
>> For more options, visit https://groups.google.com/d/optout.

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#1598856 — Re: [Outreachy kernel] [PATCH] staging: iio: ade7753: replace mlock with driver private lock

FromAlison Schofield <amsfield22@gmail.com>
Date2017-03-13 06:40 +0100
SubjectRe: [Outreachy kernel] [PATCH] staging: iio: ade7753: replace mlock with driver private lock
Message-ID<tkqS6-4bz-5@gated-at.bofh.it>
In reply to#1598840
On Mon, Mar 13, 2017 at 09:28:34AM +0530, SIMRAN SINGHAL wrote:
> On Mon, Mar 13, 2017 at 12:03 AM, Alison Schofield <amsfield22@gmail.com> wrote:
> > On Sun, Mar 12, 2017 at 07:02:50PM +0530, 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 a lock in the devices global data.
> >>
> >> Fix some coding style issues related to white space also.
> >>
> >> Signed-off-by: simran singhal <singhalsimran0@gmail.com>
> >
> > Hi Simran, This looks good to me.  Let's see what the
> > reviewers say.  I think the white space stuff is ok,
> > since it was right where you were editing.
> > alisons
> >
> Alison, so sending this patch here on outreachy mailing list is fine.
> Still confuse :P

You are OK.  You sent it to everyone suggested in the Task Description.

This patch was sent before I posted the Task Description.  I'm assuming
that since then you've found the posted Task:
https://kernelnewbies.org/IIO_tasks 
Find Coding Task 2 --> "PATCHES need to be sent to all of:"

> 
> >> ---
> >>  drivers/staging/iio/meter/ade7753.c | 14 ++++++++------
> >>  1 file changed, 8 insertions(+), 6 deletions(-)
> >>
> >> diff --git a/drivers/staging/iio/meter/ade7753.c b/drivers/staging/iio/meter/ade7753.c
> >> index dfd8b71..ca99d82 100644
> >> --- a/drivers/staging/iio/meter/ade7753.c
> >> +++ b/drivers/staging/iio/meter/ade7753.c
> >> @@ -81,12 +81,14 @@
> >>   * @tx:         transmit buffer
> >>   * @rx:         receive buffer
> >>   * @buf_lock:       mutex to protect tx and rx
> >> + * @lock:    protect sensor state
> >>   **/
> >>  struct ade7753_state {
> >> -         struct spi_device   *us;
> >> -                 struct mutex        buf_lock;
> >> -                         u8          tx[ADE7753_MAX_TX] ____cacheline_aligned;
> >> -                                 u8          rx[ADE7753_MAX_RX];
> >> +     struct spi_device   *us;
> >> +     struct mutex        buf_lock;
> >> +     struct mutex        lock;       /* protect sensor state */
> >> +     u8          tx[ADE7753_MAX_TX] ____cacheline_aligned;
> >> +     u8          rx[ADE7753_MAX_RX];
> >>  };
> >>
> >>  static int ade7753_spi_write_reg_8(struct device *dev,
> >> @@ -484,7 +486,7 @@ static ssize_t ade7753_write_frequency(struct device *dev,
> >>       if (!val)
> >>               return -EINVAL;
> >>
> >> -     mutex_lock(&indio_dev->mlock);
> >> +     mutex_lock(&st->lock);
> >>
> >>       t = 27900 / val;
> >>       if (t > 0)
> >> @@ -505,7 +507,7 @@ static ssize_t ade7753_write_frequency(struct device *dev,
> >>       ret = ade7753_spi_write_reg_16(dev, ADE7753_MODE, reg);
> >>
> >>  out:
> >> -     mutex_unlock(&indio_dev->mlock);
> >> +     mutex_unlock(&st->lock);
> >>
> >>       return ret ? ret : len;
> >>  }
> >> --
> >> 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/20170312133250.GA7772%40singhal-Inspiron-5558.
> >> For more options, visit https://groups.google.com/d/optout.

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#1599263 — Re: [PATCH] staging: iio: ade7753: replace mlock with driver private lock

FromLars-Peter Clausen <lars@metafoo.de>
Date2017-03-13 13:10 +0100
SubjectRe: [PATCH] staging: iio: ade7753: replace mlock with driver private lock
Message-ID<tkwXw-jQ-11@gated-at.bofh.it>
In reply to#1598623
On 03/12/2017 02:32 PM, 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 a lock in the devices global data.
> 
> Fix some coding style issues related to white space also.
> 
> Signed-off-by: simran singhal <singhalsimran0@gmail.com>
> ---
>  drivers/staging/iio/meter/ade7753.c | 14 ++++++++------
>  1 file changed, 8 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/staging/iio/meter/ade7753.c b/drivers/staging/iio/meter/ade7753.c
> index dfd8b71..ca99d82 100644
> --- a/drivers/staging/iio/meter/ade7753.c
> +++ b/drivers/staging/iio/meter/ade7753.c
> @@ -81,12 +81,14 @@
>   * @tx:         transmit buffer
>   * @rx:         receive buffer
>   * @buf_lock:       mutex to protect tx and rx
> + * @lock:	protect sensor state

It might make sense to reuse the existing lock which currently protects the
read/write functions. You can do this by introducing a variant of
ade7753_spi_{read,write}_reg_16() that does not take a lock and use these to
implement the read-modify-write cycle in a protected section.

Looking through the driver there seem to be other places as well that do
read-modify-write that should be protected by a lock, but currently are not.
This might be a good task.

>   **/
>  struct ade7753_state {
> -	    struct spi_device   *us;
> -		    struct mutex        buf_lock;
> -			    u8          tx[ADE7753_MAX_TX] ____cacheline_aligned;
> -				    u8          rx[ADE7753_MAX_RX];
> +	struct spi_device   *us;
> +	struct mutex        buf_lock;
> +	struct mutex        lock;	/* protect sensor state */
> +	u8          tx[ADE7753_MAX_TX] ____cacheline_aligned;
> +	u8          rx[ADE7753_MAX_RX];
>  };
>  
>  static int ade7753_spi_write_reg_8(struct device *dev,
> @@ -484,7 +486,7 @@ static ssize_t ade7753_write_frequency(struct device *dev,
>  	if (!val)
>  		return -EINVAL;
>  
> -	mutex_lock(&indio_dev->mlock);
> +	mutex_lock(&st->lock);
>  
>  	t = 27900 / val;
>  	if (t > 0)
> @@ -505,7 +507,7 @@ static ssize_t ade7753_write_frequency(struct device *dev,
>  	ret = ade7753_spi_write_reg_16(dev, ADE7753_MODE, reg);
>  
>  out:
> -	mutex_unlock(&indio_dev->mlock);
> +	mutex_unlock(&st->lock);
>  
>  	return ret ? ret : len;
>  }
>

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#1599280

FromSIMRAN SINGHAL <singhalsimran0@gmail.com>
Date2017-03-13 13:40 +0100
Message-ID<tkxqx-uQ-3@gated-at.bofh.it>
In reply to#1599263
On Mon, Mar 13, 2017 at 5:30 PM, Lars-Peter Clausen <lars@metafoo.de> wrote:
> On 03/12/2017 02:32 PM, 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 a lock in the devices global data.
>>
>> Fix some coding style issues related to white space also.
>>
>> Signed-off-by: simran singhal <singhalsimran0@gmail.com>
>> ---
>>  drivers/staging/iio/meter/ade7753.c | 14 ++++++++------
>>  1 file changed, 8 insertions(+), 6 deletions(-)
>>
>> diff --git a/drivers/staging/iio/meter/ade7753.c b/drivers/staging/iio/meter/ade7753.c
>> index dfd8b71..ca99d82 100644
>> --- a/drivers/staging/iio/meter/ade7753.c
>> +++ b/drivers/staging/iio/meter/ade7753.c
>> @@ -81,12 +81,14 @@
>>   * @tx:         transmit buffer
>>   * @rx:         receive buffer
>>   * @buf_lock:       mutex to protect tx and rx
>> + * @lock:    protect sensor state
>
> It might make sense to reuse the existing lock which currently protects the
> read/write functions. You can do this by introducing a variant of
> ade7753_spi_{read,write}_reg_16() that does not take a lock and use these to
> implement the read-modify-write cycle in a protected section.
>
> Looking through the driver there seem to be other places as well that do
> read-modify-write that should be protected by a lock, but currently are not.
> This might be a good task.
>

Are you trying to say that their is no need of introducing "lock",
I can using "buf_lock" only.

Thanks!

>>   **/
>>  struct ade7753_state {
>> -         struct spi_device   *us;
>> -                 struct mutex        buf_lock;
>> -                         u8          tx[ADE7753_MAX_TX] ____cacheline_aligned;
>> -                                 u8          rx[ADE7753_MAX_RX];
>> +     struct spi_device   *us;
>> +     struct mutex        buf_lock;
>> +     struct mutex        lock;       /* protect sensor state */
>> +     u8          tx[ADE7753_MAX_TX] ____cacheline_aligned;
>> +     u8          rx[ADE7753_MAX_RX];
>>  };
>>
>>  static int ade7753_spi_write_reg_8(struct device *dev,
>> @@ -484,7 +486,7 @@ static ssize_t ade7753_write_frequency(struct device *dev,
>>       if (!val)
>>               return -EINVAL;
>>
>> -     mutex_lock(&indio_dev->mlock);
>> +     mutex_lock(&st->lock);
>>
>>       t = 27900 / val;
>>       if (t > 0)
>> @@ -505,7 +507,7 @@ static ssize_t ade7753_write_frequency(struct device *dev,
>>       ret = ade7753_spi_write_reg_16(dev, ADE7753_MODE, reg);
>>
>>  out:
>> -     mutex_unlock(&indio_dev->mlock);
>> +     mutex_unlock(&st->lock);
>>
>>       return ret ? ret : len;
>>  }
>>
>

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#1599408 — Re: [PATCH] staging: iio: ade7753: replace mlock with driver private lock

FromLars-Peter Clausen <lars@metafoo.de>
Date2017-03-13 15:10 +0100
SubjectRe: [PATCH] staging: iio: ade7753: replace mlock with driver private lock
Message-ID<tkyPD-1D6-23@gated-at.bofh.it>
In reply to#1599280
On 03/13/2017 01:33 PM, SIMRAN SINGHAL wrote:
> On Mon, Mar 13, 2017 at 5:30 PM, Lars-Peter Clausen <lars@metafoo.de> wrote:
>> On 03/12/2017 02:32 PM, 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 a lock in the devices global data.
>>>
>>> Fix some coding style issues related to white space also.
>>>
>>> Signed-off-by: simran singhal <singhalsimran0@gmail.com>
>>> ---
>>>  drivers/staging/iio/meter/ade7753.c | 14 ++++++++------
>>>  1 file changed, 8 insertions(+), 6 deletions(-)
>>>
>>> diff --git a/drivers/staging/iio/meter/ade7753.c b/drivers/staging/iio/meter/ade7753.c
>>> index dfd8b71..ca99d82 100644
>>> --- a/drivers/staging/iio/meter/ade7753.c
>>> +++ b/drivers/staging/iio/meter/ade7753.c
>>> @@ -81,12 +81,14 @@
>>>   * @tx:         transmit buffer
>>>   * @rx:         receive buffer
>>>   * @buf_lock:       mutex to protect tx and rx
>>> + * @lock:    protect sensor state
>>
>> It might make sense to reuse the existing lock which currently protects the
>> read/write functions. You can do this by introducing a variant of
>> ade7753_spi_{read,write}_reg_16() that does not take a lock and use these to
>> implement the read-modify-write cycle in a protected section.
>>
>> Looking through the driver there seem to be other places as well that do
>> read-modify-write that should be protected by a lock, but currently are not.
>> This might be a good task.
>>
> 
> Are you trying to say that their is no need of introducing "lock",
> I can using "buf_lock" only.

Yes, there should be no need for two locks. But you need to slightly
refactor the code to avoid taking the same lock nested.

> 
> Thanks!
> 
>>>   **/
>>>  struct ade7753_state {
>>> -         struct spi_device   *us;
>>> -                 struct mutex        buf_lock;
>>> -                         u8          tx[ADE7753_MAX_TX] ____cacheline_aligned;
>>> -                                 u8          rx[ADE7753_MAX_RX];
>>> +     struct spi_device   *us;
>>> +     struct mutex        buf_lock;
>>> +     struct mutex        lock;       /* protect sensor state */
>>> +     u8          tx[ADE7753_MAX_TX] ____cacheline_aligned;
>>> +     u8          rx[ADE7753_MAX_RX];
>>>  };
>>>
>>>  static int ade7753_spi_write_reg_8(struct device *dev,
>>> @@ -484,7 +486,7 @@ static ssize_t ade7753_write_frequency(struct device *dev,
>>>       if (!val)
>>>               return -EINVAL;
>>>
>>> -     mutex_lock(&indio_dev->mlock);
>>> +     mutex_lock(&st->lock);
>>>
>>>       t = 27900 / val;
>>>       if (t > 0)
>>> @@ -505,7 +507,7 @@ static ssize_t ade7753_write_frequency(struct device *dev,
>>>       ret = ade7753_spi_write_reg_16(dev, ADE7753_MODE, reg);
>>>
>>>  out:
>>> -     mutex_unlock(&indio_dev->mlock);
>>> +     mutex_unlock(&st->lock);
>>>
>>>       return ret ? ret : len;
>>>  }
>>>
>>

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