Hi, On Wed, Mar 30, 2011 at 9:09 PM, swathi suresh <swathi.suresh07@gmail.com> wrote:
On Wed, Mar 30, 2011 at 10:42 PM, sk.syed2 <sk.syed2@gmail.com> wrote:
struct page *page = virt_to_page(skb->data); int offset = (unsigned long) skb->data - (unsigned long) page_address(page); skb_add_rx_frag(master_skb, skb_shinfo(master_skb)->nr_frags, page, offset, skb->len) . . is this the right way to do ? This will work if skb->len < PAGE_SIZE, otherwise it means it spans more than a page and you need to do skb_add_rx_frag for each PAGE_SIZE data present. Refer to Understanding Linux network internals By Christian Benvenuti p 488/489.
Thanks Syed, skb->len is always smaller then PAGE_SIZE because i have set the mtu size as 1500 from my network driver. But am facing kernel panic, if i just the moment the driver call dev_queue_xmit, so i guess this may not be right way to get the page.
It isn't sufficient for skb->len to just be less than PAGE_SIZE. offset + skb->len also has to be less than PAGE_SIZE, otherwise your data will cross into a different page. -- Dave Hylands Shuswap, BC, Canada http://www.davehylands.com