Re: A couple of questions about the SKB fragments

2016-05-05 14:13 GMT+03:00 Edward Cree [off-list ref]:

On 05/05/16 08:40, Ilya Matveychikov wrote:

quoted

Is there any docs except the kernel sources itself to refer to?

davem has some docs up at http://vger.kernel.org/~davem/skb.html and
http://vger.kernel.org/~davem/skb_data.html
In particular note the following:
"The frag_list is used to maintain a chain of SKBs organized for
 fragmentation purposes, it is _not_ used for maintaining paged data."
So my reading would suggest there is no way to multiple-layer-fragment
an SKB; the frags are page pointers and offsets, not entire sk_buff
structs in their own right.

Seems that the docs is slightly outdated. I think the structure of SKB does
not impose any restrictions on the nesting of the fragments. But is there
any of them in the kernel's code?