add quantum info to read handler + fix slice update

[joncnet]

Regarding the double lock acquisition:

https://github.com/kohler/click/blob/master/include/click/sync.hh

/* @brief Acquires the ReadWriteLock for writing.

• On return, this thread has acquired the lock for writing. The function
• will spin indefinitely until the lock is acquired. It is OK to acquire a
• lock you have already acquired, but you must release it as many times as
• you have acquired it.
• @sa ReadWriteLock::acquire_read */ inline void ReadWriteLock::acquire_write() {

  if CLICK_LINUXMODULE && defined(CONFIG_SMP)

  for (unsigned i = 0; i < (unsigned) num_possible_cpus(); i++) _l[i]._lock.acquire();

  endif

  }