/**
* Allocate a new skb that can hold data of length @len.
*
* An SKB is created complely headerless. The linear part of an SKB
* is set apart for headers, and stream data is placed in paged fragments.
* Lower layers will take care of prepending all required headers.
*/
struct sk_buff *
ss_skb_alloc_pages(size_t len)
{
int i_frag, nr_frags = DIV_ROUND_UP(len, PAGE_SIZE);
struct sk_buff *skb;
BUG_ON(nr_frags > MAX_SKB_FRAGS);
skb = ss_skb_alloc();
if (!skb)
return NULL;
for (i_frag = 0; i_frag < nr_frags; ++i_frag) {
struct page *page = alloc_page(GFP_ATOMIC);
if (!page) {
kfree_skb(skb);
return NULL;
}
#if LINUX_VERSION_CODE < KERNEL_VERSION(4,1,12)
/* See __skb_alloc_pages() in include/linux/skbuff.h. */
if (page->pfmemalloc)
skb->pfmemalloc = true;
#endif
__skb_fill_page_desc(skb, i_frag, page, 0, 0);
skb_shinfo(skb)->nr_frags++;
}
return skb;
}
/**
* Allocate a new skb that can hold @len bytes of data.
*
* An SKB is created complely headerless. The linear part of an SKB is
* set apart for headers, and stream data is placed in paged fragments.
* Lower layers will take care of prepending all required headers.
*
* Similar to alloc_skb_with_frags() except it doesn't allocate multi-page
* fragments, and it sets up fragments with zero size.
*/
struct sk_buff *
ss_skb_alloc_pages(size_t len)
{
int i, nr_frags = DIV_ROUND_UP(len, PAGE_SIZE);
struct sk_buff *skb;
BUG_ON(nr_frags > MAX_SKB_FRAGS);
if ((skb = ss_skb_alloc()) == NULL)
return NULL;
for (i = 0; i < nr_frags; ++i) {
struct page *page = alloc_page(GFP_ATOMIC);
if (!page) {
kfree_skb(skb);
return NULL;
}
skb_fill_page_desc(skb, i, page, 0, 0);
TFW_DBG3("Created new frag %d,%p for skb %p\n",
i, page_address(page), skb);
}
return skb;
}