[RFC] soc_pcm_open: error path behavior change since v5.6

[Cezary Rojewski <cezary.rojewski@intel.com>]

Hello,

Some time ago negative-tests found out that behavior of soc_pcm_open has 
changed, quite sure this might be a regression hence my email. Till v5.6 
soc_pcm_open was invoking ::shutdown() for cpu_dai in error path only if 
::startup() succeeded first (label: 'out'). After addition of commit:

	5d9fa03e6c3514266fa94851ab1b6dd6e0595a13
	ASoC: soc-pcm: tidyup soc_pcm_open() order

this is no longer true. ::shutdown() can and will be invoked for given 
cpu_dai despite ::startup()'s failure. This complicated further since 
the merging of cpu & codec dais.

The same applies to codec_dais: notice the usage of 
for_each_rtd_codec_dai_rollback macro instead of for_each_rtd_dais in 
error path in v5.6.

Should dai's ::shutdown() be introducing some kind of state-check from 
now on? - similarly to how developers deal with some of the core pcm 
operations e.g.: ::prepare() (as it may get invoked multiple times in a 
row so check is there to prevent redundancy).
Or, perhaps behavior change should be reverted with ::shutdown() routine 
again being called only after successful ::startup()?

Czarek