Regarding skb and skb_frags

[Li Wei]

On 05/01/2014 06:42 PM, Pranay Srivastava wrote:
> I was going through a function
> 
> dev_alloc_skb
> 
> and it seems that the skb_frags are created only if the data length
> passed is > PAGE_SIZE.
> 
> My question is that an Ethernet frame won't be bigger than 1500 bytes
> [correct?] so there never will be skb_frags for Ethernet frames.

No, you should consider TSO and GSO things.

Thanks

> However I've seen skb_frags appeared when sending large data.
> 
> I'm not sure how to understand this. Does the driver pokes IP header
> to check how many fragments would be coming and decides (on the rcv
> side) how much to pass in dev_alloc_skb ?
> 
> Thanks
>