[PATCH 0/1] MR8712: strmbase: Get rid of stream_cs.

[Conor McCarthy (＠cmccarthy)]

The following sequence can occur:
sink_EndOfStream,
lock stream_cs,
renderer sink_eos,
strmbase_passthrough_eos,
IMediaSeeking_GetStopPosition,
MediaSeekingPassThru_GetStopPosition,
get_connected,
IPin_ConnectedTo,
lock filter_cs

And at the same time:
filter_Stop,
lock filter_cs,
dmo_wrapper_cleanup_stream,
lock stream_cs

Resulting in deadlock. This can occur in Space Engineers.

dmo_wrapper_cleanup_stream() locks stream_cs to access `pin.peer` and `pin.pAllocator`, which are normally protected by filter_cs, but this lock was added to fix a test failure, so I don't know if there's an alternative.

I'm concerned about the possible performance impact of removing stream_cs though.