Re: [PATCH 0/1] MR8722: mf: Add a SUBMITTED command state to avoid multiple submission of the same op.

[Rémi Bernon (＠rbernon)]

Rémi Bernon (@rbernon) commented about dlls/mf/session.c:
>          session->state = SESSION_STATE_CLOSED;
>          session_command_complete_with_event(session, MESessionClosed, MF_E_SHUTDOWN, NULL);
>          break;
> -
>    case COMMAND_STATE_SUBMITTED:
>    case COMMAND_STATE_COMPLETE:
>        if (session->state == SESSION_STATE_STARTED || session->state == SESSION_STATE_PAUSED)
>            session_set_stopped(session, MESessionStopped, MF_E_SHUTDOWN);
>        break;

```suggestion:-4+0
        case COMMAND_STATE_COMPLETE:
            if (session->state == SESSION_STATE_STARTED || session->state == SESSION_STATE_PAUSED)
                session_set_stopped(session, MESessionStopped, MF_E_SHUTDOWN);
            break;
        case COMMAND_STATE_SUBMITTED:
            break;
```

This is where the issue may come from (ie: `session_set_stopped` calling `session_command_complete` which needs to avoid submitting the command again if it was already), and I think we can simply avoid doing anything if a command has been submitted already: either it's a command that will try to use the same source and it will handle the source shutdown eventually, or it's a command that will clear the topology and already do the proper state cleanup and update.

I believe this creates a stronger invariant for session_command_complete: it can safely complete the pending command if any, without having to special case `COMMAND_STATE_SUBMITTED` itself.