Re: netfront for review

From: Gerd Hoffmann
Date: Thu May 03 2007 - 10:37:18 EST


Jeremy Fitzhardinge wrote:
Gerd Hoffmann wrote:
Gerd, in change 11196:b85da7cd9ea5 "front: Fix rx buffer leak when
tearing down an interface." you added a call to
"add_id_to_freelist(np->rx_skbs, id);". However, rx_skbs doesn't have
an extra entry for the list head, and there's never any corresponding
get_id_from_freelist(np->rx_skbs). What should it be?
The function has an effect in page flipping mode only. It walks the
whole list of rx skbufs (id is the loop variable ...), checks whenever
they are handed out to the frontend driver to fill in packet data and
not returned yet, and if so reclaim them ...

Yes, but why use add_id_to_freelist? rx_skbs are not being used on a
freelist anywhere else. It just means the rx_skb array gets filled with
small integers, but the rest of the code assumes they're either NULL or
an skb pointer.

Hmm, good point. Have to look at the code again, it has been some time I've written that, and it took me some time to figure how all the grant table stuff works ...

Maybe the add_id_to_freelist() call can simply be dropped. The whole interface is released shortly thereafter, probably thats why filling the freelist with yunk never caused any problems ...

cheers,
Gerd

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