Aniruddha Bohra wrote:
Hi,
In two drivers, fxp and em, the assumptions about entering the
ether_input routine are different.
From em_rxeof:
#ifdef DEVICE_POLLING
EM_UNLOCK()
(*ifp->if_input)()
EM_UNLOCK()
#else
(*ifp->if_input)()
#endif
While in fxp:
FXP_UNLOCK()
(*ifp->if_input)()
FXP_LOCK()
My question is :
Does ether_input() assume it is the only thread executing the code? If
it is the case, what is the
reason for dropping the lock in the DEVICE_POLLING case?
There is actually no difference between these cases. In the
!DEVICE_POLLING case, the em driver does not hold its driver lock when
it calls em_rxeof. The call is made from em_handle_rxtx, where you'll
see that the driver has not acquired a lock when it calls em_rxeof.
Thus, in all cases the if_input function is called without holding the
driver lock.
John
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