Re: [PATCH v2 5/5] iio:buffer: Ignore noop requests for iio_update_buffers()

[Jonathan Cameron <jic23@kernel.org>]

On 10/12/13 13:06, Jonathan Cameron wrote:
> On 10/12/13 11:19, Lars-Peter Clausen wrote:
>> On 10/12/2013 01:10 PM, Jonathan Cameron wrote:
>>> On 10/04/13 12:07, Lars-Peter Clausen wrote:
>>>> Since the kernel now disables all buffers when a device is unregistered it might
>>>> happen that a in-kernel consumer tries to disable that buffer again. So ignore
>>>> requests where the buffer already is in the desired state.
>>>>
>>>> Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Applied to the togreg branch of iio.git

Thanks,
>>>> ---
>>>> No changes since v1
>>>> ---
>>>>  drivers/iio/industrialio-buffer.c | 14 ++++++++++++++
>>>>  1 file changed, 14 insertions(+)
>>>>
>>>> diff --git a/drivers/iio/industrialio-buffer.c b/drivers/iio/industrialio-buffer.c
>>>> index d6a5455..fd3f3af 100644
>>>> --- a/drivers/iio/industrialio-buffer.c
>>>> +++ b/drivers/iio/industrialio-buffer.c
>>>> @@ -681,9 +681,23 @@ int iio_update_buffers(struct iio_dev *indio_dev,
>>>>  {
>>>>  	int ret;
>>>>  
>>>> +	if (insert_buffer == remove_buffer)
>>>> +		return 0;
>>>> +
>>>>  	mutex_lock(&indio_dev->info_exist_lock);
>>>>  	mutex_lock(&indio_dev->mlock);
>>>>  
>>>> +	if (insert_buffer && iio_buffer_is_active(insert_buffer))
>>>> +		insert_buffer = NULL;
>>>> +
>>>> +	if (remove_buffer && !iio_buffer_is_active(remove_buffer))
>>>> +		remove_buffer = NULL;
>>>> +
>>> So this condition will occur iff insert_buffer = 0 and remove buffer = 0?
>>>
>>> If so, then insert_buffer == remove_buffer and you'll have already returned 0 above??
>>
>> This is to catch the case where we've set one (or both) of them to NULL
>> because it was already in the requested state.
>>
> Ah, as I said. Not enough coffee ;)
>>>
>>> Entirely possible I'm needing more coffee this morning...
>>>> +	if (!insert_buffer && !remove_buffer) {
>>>> +		ret = 0;
>>>> +		goto out_unlock;
>>>> +	}
>>>> +
>>>>  	if (indio_dev->info == NULL) {
>>>>  		ret = -ENODEV;
>>>>  		goto out_unlock;
>>>>
>>> --
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>>
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