On Thu, 2014-02-27 at 13:51 -0800, Ben Greear wrote:
> That said, the code below appears to work, even if it is
> not as efficient as it might be?
>
> if (msdu_chaining) {
> struct sk_buff *next = msdu_head->next;
> struct sk_buff *to_free = next;
> int space;
> static int do_once = 1;
> msdu_head->next = NULL;
>
> if (unlikely(do_once)) {
> ath10k_warn("htt rx msdu_chaining detected %d\n",
> msdu_chaining);
> do_once = 0;
> }
>
> while (next) {
> space = next->len - skb_tailroom(msdu_head);
>
> if ((space > 0) &&
> (pskb_expand_head(msdu_head, 0, space, GFP_ATOMIC) < 0)) {
> /* TODO: bump some rx-oom error stat */
> goto outside_continue;
> }
> skb_copy_from_linear_data(next, skb_put(msdu_head, next->len),
> next->len);
> next = next->next;
> }
Yep, this is very inefficient , you might copy data very often in
pskb_expand_head(), then in skb_copy_from_linear_data()
Also, if total length is big, you end up doing high order allocations,
since you generate a linear skb. This might fail under memory pressure.
What is the maximal skb->len of resulting skb ?
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