Re: [PATCH v2 8/9] media: subdev: Refactor v4l2_subdev_enable/disable_streams()

[Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>]

On 10/04/2024 13:13, Sakari Ailus wrote:
> Moi,
> 
> Thank you for working on this.
> 
> On Fri, Apr 05, 2024 at 12:14:26PM +0300, Tomi Valkeinen wrote:
>> Add two internal helper functions, v4l2_subdev_collect_streams() and
>> v4l2_subdev_set_streams_enabled(), which allows us to refactor
>> v4l2_subdev_enable/disable_streams() functions.
>>
>> This (I think) makes the code a bit easier to read, and lets us more
>> easily add new functionality in the helper functions in the following
>> patch.
>>
>> Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>
>> ---
>>   drivers/media/v4l2-core/v4l2-subdev.c | 111 +++++++++++++++++++---------------
>>   1 file changed, 62 insertions(+), 49 deletions(-)
>>
>> diff --git a/drivers/media/v4l2-core/v4l2-subdev.c b/drivers/media/v4l2-core/v4l2-subdev.c
>> index 015f2fb423c9..6c3c9069f1e2 100644
>> --- a/drivers/media/v4l2-core/v4l2-subdev.c
>> +++ b/drivers/media/v4l2-core/v4l2-subdev.c
>> @@ -2099,6 +2099,44 @@ int v4l2_subdev_routing_validate(struct v4l2_subdev *sd,
>>   }
>>   EXPORT_SYMBOL_GPL(v4l2_subdev_routing_validate);
>>   
>> +static void v4l2_subdev_collect_streams(struct v4l2_subdev *sd,
>> +					struct v4l2_subdev_state *state,
>> +					u32 pad, u64 streams_mask,
>> +					u64 *found_streams,
>> +					u64 *enabled_streams)
>> +{
>> +	*found_streams = 0;
>> +	*enabled_streams = 0;
>> +
>> +	for (unsigned int i = 0; i < state->stream_configs.num_configs; ++i) {
>> +		const struct v4l2_subdev_stream_config *cfg;
>> +
>> +		cfg = &state->stream_configs.configs[i];
> 
> You can do the assignment in declaration.

I can, but you want the lines to be split at 80, so that'll end up being 
in two lines, which, I think, looks messier than the one above.

Usually I think doing initialization when declaring the variable is best 
done if it fits into one line.

  Tomi

> 
> Same for streams_enabled() below.
> 
>> +
>> +		if (cfg->pad != pad || !(streams_mask & BIT_ULL(cfg->stream)))
>> +			continue;
>> +
>> +		*found_streams |= BIT_ULL(cfg->stream);
>> +		if (cfg->enabled)
>> +			*enabled_streams |= BIT_ULL(cfg->stream);
>> +	}
>> +}
>> +
>> +static void v4l2_subdev_set_streams_enabled(struct v4l2_subdev *sd,
>> +					    struct v4l2_subdev_state *state,
>> +					    u32 pad, u64 streams_mask,
>> +					    bool enabled)
>> +{
>> +	for (unsigned int i = 0; i < state->stream_configs.num_configs; ++i) {
>> +		struct v4l2_subdev_stream_config *cfg;
>> +
>> +		cfg = &state->stream_configs.configs[i];
>> +
>> +		if (cfg->pad == pad && (streams_mask & BIT_ULL(cfg->stream)))
>> +			cfg->enabled = enabled;
>> +	}
>> +}
>> +
>>   static int v4l2_subdev_enable_streams_fallback(struct v4l2_subdev *sd, u32 pad,
>>   					       u64 streams_mask)
>>   {
>> @@ -2150,8 +2188,8 @@ int v4l2_subdev_enable_streams(struct v4l2_subdev *sd, u32 pad,
>>   	struct device *dev = sd->entity.graph_obj.mdev->dev;
>>   	struct v4l2_subdev_state *state;
>>   	bool already_streaming;
>> -	u64 found_streams = 0;
>> -	unsigned int i;
>> +	u64 enabled_streams;
>> +	u64 found_streams;
>>   	int ret;
>>   
>>   	/* A few basic sanity checks first. */
>> @@ -2172,22 +2210,9 @@ int v4l2_subdev_enable_streams(struct v4l2_subdev *sd, u32 pad,
>>   	 * Verify that the requested streams exist and that they are not
>>   	 * already enabled.
>>   	 */
>> -	for (i = 0; i < state->stream_configs.num_configs; ++i) {
>> -		struct v4l2_subdev_stream_config *cfg =
>> -			&state->stream_configs.configs[i];
>>   
>> -		if (cfg->pad != pad || !(streams_mask & BIT_ULL(cfg->stream)))
>> -			continue;
>> -
>> -		found_streams |= BIT_ULL(cfg->stream);
>> -
>> -		if (cfg->enabled) {
>> -			dev_dbg(dev, "stream %u already enabled on %s:%u\n",
>> -				cfg->stream, sd->entity.name, pad);
>> -			ret = -EALREADY;
>> -			goto done;
>> -		}
>> -	}
>> +	v4l2_subdev_collect_streams(sd, state, pad, streams_mask,
>> +				    &found_streams, &enabled_streams);
>>   
>>   	if (found_streams != streams_mask) {
>>   		dev_dbg(dev, "streams 0x%llx not found on %s:%u\n",
>> @@ -2196,6 +2221,13 @@ int v4l2_subdev_enable_streams(struct v4l2_subdev *sd, u32 pad,
>>   		goto done;
>>   	}
>>   
>> +	if (enabled_streams) {
>> +		dev_dbg(dev, "streams 0x%llx already enabled on %s:%u\n",
>> +			enabled_streams, sd->entity.name, pad);
>> +		ret = -EINVAL;
>> +		goto done;
>> +	}
>> +
>>   	dev_dbg(dev, "enable streams %u:%#llx\n", pad, streams_mask);
>>   
>>   	already_streaming = v4l2_subdev_is_streaming(sd);
>> @@ -2213,13 +2245,7 @@ int v4l2_subdev_enable_streams(struct v4l2_subdev *sd, u32 pad,
>>   	}
>>   
>>   	/* Mark the streams as enabled. */
>> -	for (i = 0; i < state->stream_configs.num_configs; ++i) {
>> -		struct v4l2_subdev_stream_config *cfg =
>> -			&state->stream_configs.configs[i];
>> -
>> -		if (cfg->pad == pad && (streams_mask & BIT_ULL(cfg->stream)))
>> -			cfg->enabled = true;
>> -	}
>> +	v4l2_subdev_set_streams_enabled(sd, state, pad, streams_mask, true);
>>   
>>   done:
>>   	if (ret && !already_streaming)
>> @@ -2281,8 +2307,8 @@ int v4l2_subdev_disable_streams(struct v4l2_subdev *sd, u32 pad,
>>   {
>>   	struct device *dev = sd->entity.graph_obj.mdev->dev;
>>   	struct v4l2_subdev_state *state;
>> -	u64 found_streams = 0;
>> -	unsigned int i;
>> +	u64 enabled_streams;
>> +	u64 found_streams;
>>   	int ret;
>>   
>>   	/* A few basic sanity checks first. */
>> @@ -2303,22 +2329,9 @@ int v4l2_subdev_disable_streams(struct v4l2_subdev *sd, u32 pad,
>>   	 * Verify that the requested streams exist and that they are not
>>   	 * already disabled.
>>   	 */
>> -	for (i = 0; i < state->stream_configs.num_configs; ++i) {
>> -		struct v4l2_subdev_stream_config *cfg =
>> -			&state->stream_configs.configs[i];
>>   
>> -		if (cfg->pad != pad || !(streams_mask & BIT_ULL(cfg->stream)))
>> -			continue;
>> -
>> -		found_streams |= BIT_ULL(cfg->stream);
>> -
>> -		if (!cfg->enabled) {
>> -			dev_dbg(dev, "stream %u already disabled on %s:%u\n",
>> -				cfg->stream, sd->entity.name, pad);
>> -			ret = -EALREADY;
>> -			goto done;
>> -		}
>> -	}
>> +	v4l2_subdev_collect_streams(sd, state, pad, streams_mask,
>> +				    &found_streams, &enabled_streams);
>>   
>>   	if (found_streams != streams_mask) {
>>   		dev_dbg(dev, "streams 0x%llx not found on %s:%u\n",
>> @@ -2327,6 +2340,13 @@ int v4l2_subdev_disable_streams(struct v4l2_subdev *sd, u32 pad,
>>   		goto done;
>>   	}
>>   
>> +	if (enabled_streams != streams_mask) {
>> +		dev_dbg(dev, "streams 0x%llx already disabled on %s:%u\n",
>> +			streams_mask & ~enabled_streams, sd->entity.name, pad);
>> +		ret = -EINVAL;
>> +		goto done;
>> +	}
>> +
>>   	dev_dbg(dev, "disable streams %u:%#llx\n", pad, streams_mask);
>>   
>>   	/* Call the .disable_streams() operation. */
>> @@ -2338,14 +2358,7 @@ int v4l2_subdev_disable_streams(struct v4l2_subdev *sd, u32 pad,
>>   		goto done;
>>   	}
>>   
>> -	/* Mark the streams as disabled. */
>> -	for (i = 0; i < state->stream_configs.num_configs; ++i) {
>> -		struct v4l2_subdev_stream_config *cfg =
>> -			&state->stream_configs.configs[i];
>> -
>> -		if (cfg->pad == pad && (streams_mask & BIT_ULL(cfg->stream)))
>> -			cfg->enabled = false;
>> -	}
>> +	v4l2_subdev_set_streams_enabled(sd, state, pad, streams_mask, false);
>>   
>>   done:
>>   	if (!v4l2_subdev_is_streaming(sd))
>>
>