----- Original Message ----- > i am slightly unclear of what mechanisms we use to prevent races > between interface being reconfigured (up/down/multicast setting, etc, > all causing reinitialization of the rx and tx rings) and > > i) packets from the host stack being sent out; > ii) interrupts from the network card being processed. > > I think in the old times IFF_DRV_RUNNING was used for this purpose, > but now it is not enough. > Acquiring the "core lock" in the NIC does not seem enough, either, > because newer drivers, especially multiqueue ones, have per-queue > rx and tx locks. > What I've done in my drivers is: * Lock the core mutex * Clear IFF_DRV_RUNNING * Lock/unlock each queue's lock The various Rx/Tx queue functions check for IFF_DRV_RUNNING after (re)acquiring their queue lock. See at vtnet_stop_rendezvous() at [1] for an example. > Does anyone know if there is a generic mechanism, or each driver > reimplements its own way ? > We desperately need a saner ifnet/driver interface. I think andre_at_ had some previous work in this area (and additional plans as well?). IMO, there's a lot to like on what DragonflyBSD has done in this area. [1] - http://svnweb.freebsd.org/base/user/bryanv/vtnetmq/sys/dev/virtio/network/if_vtnet.c?revision=252451&view=markup > thanks > luigi > _______________________________________________ > freebsd-current_at_freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-current > To unsubscribe, send any mail to "freebsd-current-unsubscribe_at_freebsd.org" >Received on Mon Aug 05 2013 - 12:59:44 UTC
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