Re: [PATCH] TX_RING and packet mmap

[Johann Baudy <johann.baudy@gnu-log.net>]

Thanks Evgeniy,

So if my understanding is correct, there is no way to get original
fragment address in destructor using skb fragment page/data.

Then,
I can't use fragments due to skb_linearize
I can't hide pointer into skb data due to skb_copy.
I can't rely on other fields of skb.
IMHO, using skb pointer requires too much cpu resources (parsing
headers to identify the right buffer...)

So what can I do except using a new field?
What do you think about adding a new field that is always linked to destructor?
I mean adding a generic new field skb->destructor_arg.

Currently if someone want to change destructor, it stores old
destructor before substitution; and executes it at the end of new
destructor. (ex: dev_gso_skb_destructor(struct sk_buff *skb))

Can we just add same mechanism for a new argument?
If someone needs destructor_arg, it saves the old value somewhere; and
restores it before calling old destructor (in the new destructor).
This way everybody can forward data to his destructor properly.

 Is it conceivable?

Thanks for your help,
Johann


-- 
Johann Baudy
johaahn@gmail.com