the do_status is queried from the Tx code frequently. To reduce
chances to delay the execution because the RLC Rx side is currently
holding the mutex we can use an atomic.
the patch uses try-lock whenever a status PDU is tried
to be built. This makes sure that when the lock is currently
hold (e.g. by a thread processing rx PDUs) the generation
of the status PDUs is not taking too long and blocking the calling
thread. Instead the status PDU generation is deferred to the next
Tx opportunity.
It's a probabilistic approach that assumes that at some stage the
lock can in fact be acquired.
Andre Puschmann
Codebot
Pedro Alvarez