Re: [PATCH v2 01/23] media: iris: Skip destroying internal buffer if not dequeued

[Vikash Garodia <quic_vgarodia@quicinc.com>]

On 4/30/2025 11:08 AM, Dikshita Agarwal wrote:
> 
> 
> On 4/29/2025 6:17 PM, Nicolas Dufresne wrote:
>> Not mine to review, but wanted to highlight some best practices,
>>
>> comment below...
>>
>> Le lundi 28 avril 2025 à 14:58 +0530, Dikshita Agarwal a écrit :
>>> Firmware might hold the DPB buffers for reference in case of sequence
>>> change, so skip destroying buffers for which QUEUED flag is not removed.
>>> Also, make sure that all buffers are released during streamoff.
>>>
>>> Cc: stable@vger.kernel.org
>>> Fixes: 73702f45db81 ("media: iris: allocate, initialize and queue internal buffers")
>>> Signed-off-by: Dikshita Agarwal <quic_dikshita@quicinc.com>
>>> ---
>>>  drivers/media/platform/qcom/iris/iris_buffer.c | 37 +++++++++++++++++++++++++-
>>>  drivers/media/platform/qcom/iris/iris_buffer.h |  3 ++-
>>>  drivers/media/platform/qcom/iris/iris_vdec.c   |  4 +--
>>>  drivers/media/platform/qcom/iris/iris_vidc.c   |  6 +++--
>>>  4 files changed, 44 insertions(+), 6 deletions(-)
>>>
>>> diff --git a/drivers/media/platform/qcom/iris/iris_buffer.c b/drivers/media/platform/qcom/iris/iris_buffer.c
>>> index e5c5a564fcb8..606d76b10be2 100644
>>> --- a/drivers/media/platform/qcom/iris/iris_buffer.c
>>> +++ b/drivers/media/platform/qcom/iris/iris_buffer.c
>>> @@ -376,7 +376,7 @@ int iris_destroy_internal_buffer(struct iris_inst *inst, struct iris_buffer *buf
>>>  	return 0;
>>>  }
>>>  
>>> -int iris_destroy_internal_buffers(struct iris_inst *inst, u32 plane)
>>> +int iris_destroy_internal_buffers(struct iris_inst *inst, u32 plane, bool force)
>>
>> Its always tempting to just glue a boolean at the end of a parameter
>> list. But this has huge downside in code readability, see below...
>>
>>>  {
>>>  	const struct iris_platform_data *platform_data = inst->core->iris_platform_data;
>>>  	struct iris_buffer *buf, *next;
>>> @@ -396,6 +396,14 @@ int iris_destroy_internal_buffers(struct iris_inst *inst, u32 plane)
>>>  	for (i = 0; i < len; i++) {
>>>  		buffers = &inst->buffers[internal_buf_type[i]];
>>>  		list_for_each_entry_safe(buf, next, &buffers->list, list) {
>>> +			/*
>>> +			 * during stream on, skip destroying internal(DPB) buffer
>>> +			 * if firmware did not return it.
>>> +			 * during close, destroy all buffers irrespectively.
>>> +			 */
>>> +			if (!force && buf->attr & BUF_ATTR_QUEUED)
>>> +				continue;
>>> +
>>>  			ret = iris_destroy_internal_buffer(inst, buf);
>>>  			if (ret)
>>>  				return ret;
>>> @@ -446,6 +454,33 @@ static int iris_release_input_internal_buffers(struct iris_inst *inst)
>>>  	return 0;
>>>  }
>>>  
>>> +void iris_get_num_queued_internal_buffers(struct iris_inst *inst, u32 plane)
>>> +{
>>> +	const struct iris_platform_data *platform_data = inst->core->iris_platform_data;
>>> +	struct iris_buffer *buf, *next;
>>> +	struct iris_buffers *buffers;
>>> +	const u32 *internal_buf_type;
>>> +	u32 internal_buffer_count, i;
>>> +	u32 count = 0;
>>> +
>>> +	if (V4L2_TYPE_IS_OUTPUT(plane)) {
>>> +		internal_buf_type = platform_data->dec_ip_int_buf_tbl;
>>> +		internal_buffer_count = platform_data->dec_ip_int_buf_tbl_size;
>>> +	} else {
>>> +		internal_buf_type = platform_data->dec_op_int_buf_tbl;
>>> +		internal_buffer_count = platform_data->dec_op_int_buf_tbl_size;
>>> +	}
>>> +
>>> +	for (i = 0; i < internal_buffer_count; i++) {
>>> +		buffers = &inst->buffers[internal_buf_type[i]];
>>> +		list_for_each_entry_safe(buf, next, &buffers->list, list)
>>> +			count++;
>>> +		if (count)
>>> +			dev_err(inst->core->dev, "%d buffer of type %d not released",
>>> +				count, internal_buf_type[i]);
>>> +	}
>>> +}
>>> +
>>>  int iris_alloc_and_queue_persist_bufs(struct iris_inst *inst)
>>>  {
>>>  	struct iris_buffers *buffers = &inst->buffers[BUF_PERSIST];
>>> diff --git a/drivers/media/platform/qcom/iris/iris_buffer.h b/drivers/media/platform/qcom/iris/iris_buffer.h
>>> index c36b6347b077..03a32b91cf21 100644
>>> --- a/drivers/media/platform/qcom/iris/iris_buffer.h
>>> +++ b/drivers/media/platform/qcom/iris/iris_buffer.h
>>> @@ -106,7 +106,8 @@ void iris_get_internal_buffers(struct iris_inst *inst, u32 plane);
>>>  int iris_create_internal_buffers(struct iris_inst *inst, u32 plane);
>>>  int iris_queue_internal_buffers(struct iris_inst *inst, u32 plane);
>>>  int iris_destroy_internal_buffer(struct iris_inst *inst, struct iris_buffer *buffer);
>>> -int iris_destroy_internal_buffers(struct iris_inst *inst, u32 plane);
>>> +int iris_destroy_internal_buffers(struct iris_inst *inst, u32 plane, bool force);
>>> +void iris_get_num_queued_internal_buffers(struct iris_inst *inst, u32 plane);
>>>  int iris_alloc_and_queue_persist_bufs(struct iris_inst *inst);
>>>  int iris_alloc_and_queue_input_int_bufs(struct iris_inst *inst);
>>>  int iris_queue_buffer(struct iris_inst *inst, struct iris_buffer *buf);
>>> diff --git a/drivers/media/platform/qcom/iris/iris_vdec.c b/drivers/media/platform/qcom/iris/iris_vdec.c
>>> index 4143acedfc57..2c1a7162d2da 100644
>>> --- a/drivers/media/platform/qcom/iris/iris_vdec.c
>>> +++ b/drivers/media/platform/qcom/iris/iris_vdec.c
>>> @@ -408,7 +408,7 @@ int iris_vdec_streamon_input(struct iris_inst *inst)
>>>  
>>>  	iris_get_internal_buffers(inst, V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE);
>>>  
>>> -	ret = iris_destroy_internal_buffers(inst, V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE);
>>> +	ret = iris_destroy_internal_buffers(inst, V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE, false);
>>>  	if (ret)
>>>  		return ret;
>>>  
>>> @@ -496,7 +496,7 @@ int iris_vdec_streamon_output(struct iris_inst *inst)
>>>  
>>>  	iris_get_internal_buffers(inst, V4L2_BUF_TYPE_VIDEO_CAPTURE_MPLANE);
>>>  
>>> -	ret = iris_destroy_internal_buffers(inst, V4L2_BUF_TYPE_VIDEO_CAPTURE_MPLANE);
>>> +	ret = iris_destroy_internal_buffers(inst, V4L2_BUF_TYPE_VIDEO_CAPTURE_MPLANE, false);
>>
>> If I was reviewing some changes (or even debugging) this specific C
>> file, I would not be able to understanding what this "false" means. I
>> would have to spend extra time, opening the declaration, going back and
>> forth, and breaking the flow.
>>
>> An alternative approach is to keep the boolean parameter in a static
>> function (c local), and then add two function wrappers that have
>> explicit names.
>>
> Sure, I can implement the alternative approach, if recommended.
> 
> If I understand correctly, you are suggesting to have one static helper and
> two wrappers around this. like:
> 
> static int iris_destroy_internal_buffers(struct iris_inst *inst, u32 plane,
> bool force)
> {
> 	...
> 	list_for_each_entry_safe(buf, next, &buffers->list, list) {
>        		if (!force && buf->attr & BUF_ATTR_QUEUED)
> 			continue;
> 		...
> 	}
> 	...
> }
> 
> //called during stream on
> int iris_destroy_dequeued_internal_buffers(struct iris_inst *inst, u32 plane)
Name this iris_force_destroy...That way, it is easy for caller to understand
without the need to interpret the boolean.

Regards,
Vikash
> {
> 	return iris_destroy_internal_buffers(inst, plane, false)
> }
> 
> //called during close
> int iris_destroy_all_internal_buffers(struct iris_inst *inst, u32 plane)
> {
> 	return iris_destroy_internal_buffers(inst, plane, true)
> }
> 
> Thanks,
> Dikshita
>> regards,
>> Nicolas
>>
>>>  	if (ret)
>>>  		return ret;
>>>  
>>> diff --git a/drivers/media/platform/qcom/iris/iris_vidc.c b/drivers/media/platform/qcom/iris/iris_vidc.c
>>> index ca0f4e310f77..56531a7f0dfe 100644
>>> --- a/drivers/media/platform/qcom/iris/iris_vidc.c
>>> +++ b/drivers/media/platform/qcom/iris/iris_vidc.c
>>> @@ -233,8 +233,10 @@ int iris_close(struct file *filp)
>>>  	iris_session_close(inst);
>>>  	iris_inst_change_state(inst, IRIS_INST_DEINIT);
>>>  	iris_v4l2_fh_deinit(inst);
>>> -	iris_destroy_internal_buffers(inst, V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE);
>>> -	iris_destroy_internal_buffers(inst, V4L2_BUF_TYPE_VIDEO_CAPTURE_MPLANE);
>>> +	iris_destroy_internal_buffers(inst, V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE, true);
>>> +	iris_destroy_internal_buffers(inst, V4L2_BUF_TYPE_VIDEO_CAPTURE_MPLANE, true);
>>> +	iris_get_num_queued_internal_buffers(inst, V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE);
>>> +	iris_get_num_queued_internal_buffers(inst, V4L2_BUF_TYPE_VIDEO_CAPTURE_MPLANE);
>>>  	iris_remove_session(inst);
>>>  	mutex_unlock(&inst->lock);
>>>  	mutex_destroy(&inst->ctx_q_lock);
>>