smx_read_fifo in smx_tf_read_inputs

[moiri]

The function smx_tf_read_inputs makes a call to smx_fifo_read. This is bad for two reasons:

• the channel state is set without mutex-locking.
• a fifo connected to a temporal firewall is always decoupled at its output, i.e. smx_fifo_d_read must be called.

To solve both issues, use smx_channel_read instead of smx_fifo_read.

[moiri]

In hindsight I now understand that this was done on purpose: A TF should not create a backup for each read which is why the standard read function was used instead of the decoupled version.

To make things clearer two new types of FIFO were introduced (see adad93eb97bbc64d00ea3057d864b278fad7a023)