Re: [PATCH v2 5/5] soundwire: stream: Remove unnecessary gotos

[Pierre-Louis Bossart]

On 6/2/23 05:11, Charles Keepax wrote:
> There is a lot of code using gotos to skip small sections of code, this
> is a fairly dubious use of a goto, especially when the level of
> intentation is really low. Most of this code doesn't even breach 80
> characters when naively shifted over.
> 
> Simplify the code a bit, by replacing these unnecessary gotos with
> simple ifs.
> 
> Signed-off-by: Charles Keepax <ckeepax@xxxxxxxxxxxxxxxxxxxxx>
> ---
> 
> Changes since v1:
>  - Split out the inversion of the alloc_*_rt logic
> 
> Worth noting this patch has no functional corrections it is just a
> stylistic change, so as Pierre said on v1 we could just leave things
> as is. Personally, I would prefer to merge it though, whilst the diff
> is a little more of a pain to review (hopefully eased somewhat by
> splitting out the alloc_*_rt logic into a separate patch), the
> resulting code reads much nicer and the code will be read a lot more
> times than this patch will be.

Indeed, the resulting code is much nicer to look at. I ignored the diffs
and just looked at the result to make up my mind.

Reviewed-by: Pierre-Louis Bossart <pierre-louis.bossart@xxxxxxxxxxxxxxx>

> 
> Thanks,
> Charles
> 
>  drivers/soundwire/stream.c | 124 +++++++++++++++++--------------------
>  1 file changed, 56 insertions(+), 68 deletions(-)
> 
> diff --git a/drivers/soundwire/stream.c b/drivers/soundwire/stream.c
> index df5600a80c174..93baca08a0dea 100644
> --- a/drivers/soundwire/stream.c
> +++ b/drivers/soundwire/stream.c
> @@ -1355,25 +1355,23 @@ static int _sdw_prepare_stream(struct sdw_stream_runtime *stream,
>  			return -EINVAL;
>  		}
>  
> -		if (!update_params)
> -			goto program_params;
> -
> -		/* Increment cumulative bus bandwidth */
> -		/* TODO: Update this during Device-Device support */
> -		bus->params.bandwidth += m_rt->stream->params.rate *
> -			m_rt->ch_count * m_rt->stream->params.bps;
> -
> -		/* Compute params */
> -		if (bus->compute_params) {
> -			ret = bus->compute_params(bus);
> -			if (ret < 0) {
> -				dev_err(bus->dev, "Compute params failed: %d\n",
> -					ret);
> -				goto restore_params;
> +		if (update_params) {
> +			/* Increment cumulative bus bandwidth */
> +			/* TODO: Update this during Device-Device support */
> +			bus->params.bandwidth += m_rt->stream->params.rate *
> +				m_rt->ch_count * m_rt->stream->params.bps;
> +
> +			/* Compute params */
> +			if (bus->compute_params) {
> +				ret = bus->compute_params(bus);
> +				if (ret < 0) {
> +					dev_err(bus->dev, "Compute params failed: %d\n",
> +						ret);
> +					goto restore_params;
> +				}
>  			}
>  		}
>  
> -program_params:
>  		/* Program params */
>  		ret = sdw_program_params(bus, true);
>  		if (ret < 0) {
> @@ -1876,30 +1874,25 @@ int sdw_stream_add_master(struct sdw_bus *bus,
>  	 * it first), if so skip allocation and go to configuration
>  	 */
>  	m_rt = sdw_master_rt_find(bus, stream);
> -	if (m_rt)
> -		goto skip_alloc_master_rt;
> -
> -	m_rt = sdw_master_rt_alloc(bus, stream);
>  	if (!m_rt) {
> -		dev_err(bus->dev, "%s: Master runtime alloc failed for stream:%s\n",
> -			__func__, stream->name);
> -		ret = -ENOMEM;
> -		goto unlock;
> -	}
> -
> -	alloc_master_rt = true;
> -skip_alloc_master_rt:
> -
> -	if (sdw_master_port_allocated(m_rt))
> -		goto skip_alloc_master_port;
> +		m_rt = sdw_master_rt_alloc(bus, stream);
> +		if (!m_rt) {
> +			dev_err(bus->dev, "%s: Master runtime alloc failed for stream:%s\n",
> +				__func__, stream->name);
> +			ret = -ENOMEM;
> +			goto unlock;
> +		}
>  
> -	ret = sdw_master_port_alloc(m_rt, num_ports);
> -	if (ret)
> -		goto alloc_error;
> +		alloc_master_rt = true;
> +	}
>  
> -	stream->m_rt_count++;
> +	if (!sdw_master_port_allocated(m_rt)) {
> +		ret = sdw_master_port_alloc(m_rt, num_ports);
> +		if (ret)
> +			goto alloc_error;
>  
> -skip_alloc_master_port:
> +		stream->m_rt_count++;
> +	}
>  
>  	ret = sdw_master_rt_config(m_rt, stream_config);
>  	if (ret < 0)
> @@ -1992,46 +1985,41 @@ int sdw_stream_add_slave(struct sdw_slave *slave,
>  	 * and go to configuration
>  	 */
>  	m_rt = sdw_master_rt_find(slave->bus, stream);
> -	if (m_rt)
> -		goto skip_alloc_master_rt;
> -
> -	/*
> -	 * If this API is invoked by Slave first then m_rt is not valid.
> -	 * So, allocate m_rt and add Slave to it.
> -	 */
> -	m_rt = sdw_master_rt_alloc(slave->bus, stream);
>  	if (!m_rt) {
> -		dev_err(&slave->dev, "%s: Master runtime alloc failed for stream:%s\n",
> -			__func__, stream->name);
> -		ret = -ENOMEM;
> -		goto unlock;
> -	}
> +		/*
> +		 * If this API is invoked by Slave first then m_rt is not valid.
> +		 * So, allocate m_rt and add Slave to it.
> +		 */
> +		m_rt = sdw_master_rt_alloc(slave->bus, stream);
> +		if (!m_rt) {
> +			dev_err(&slave->dev, "%s: Master runtime alloc failed for stream:%s\n",
> +				__func__, stream->name);
> +			ret = -ENOMEM;
> +			goto unlock;
> +		}
>  
> -	alloc_master_rt = true;
> +		alloc_master_rt = true;
> +	}
>  
> -skip_alloc_master_rt:
>  	s_rt = sdw_slave_rt_find(slave, stream);
> -	if (s_rt)
> -		goto skip_alloc_slave_rt;
> -
> -	s_rt = sdw_slave_rt_alloc(slave, m_rt);
>  	if (!s_rt) {
> -		dev_err(&slave->dev, "Slave runtime alloc failed for stream:%s\n", stream->name);
> -		ret = -ENOMEM;
> -		goto alloc_error;
> -	}
> -
> -	alloc_slave_rt = true;
> +		s_rt = sdw_slave_rt_alloc(slave, m_rt);
> +		if (!s_rt) {
> +			dev_err(&slave->dev, "Slave runtime alloc failed for stream:%s\n",
> +				stream->name);
> +			ret = -ENOMEM;
> +			goto alloc_error;
> +		}
>  
> -skip_alloc_slave_rt:
> -	if (sdw_slave_port_allocated(s_rt))
> -		goto skip_port_alloc;
> +		alloc_slave_rt = true;
> +	}
>  
> -	ret = sdw_slave_port_alloc(slave, s_rt, num_ports);
> -	if (ret)
> -		goto alloc_error;
> +	if (!sdw_slave_port_allocated(s_rt)) {
> +		ret = sdw_slave_port_alloc(slave, s_rt, num_ports);
> +		if (ret)
> +			goto alloc_error;
> +	}
>  
> -skip_port_alloc:
>  	ret =  sdw_master_rt_config(m_rt, stream_config);
>  	if (ret)
>  		goto unlock;