jdp at polstra.com
Sat Mar 17 22:11:55 UTC 2007
Aniruddha Bohra wrote:
> In two drivers, fxp and em, the assumptions about entering the
> ether_input routine are different.
> From em_rxeof:
> #ifdef DEVICE_POLLING
> While in fxp:
> 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
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