On 28/06/2021 12.47, Maciej Fijalkowski wrote:
+static __always_inline struct sk_buff *
+xdp_construct_skb(struct xdp_buff *xdp, struct napi_struct *napi)
+{
I don't like the generic name "xdp_construct_skb".
What about calling it "xdp_copy_construct_skb", because below is
memcpy'ing the data.
Functions that use this call free (or recycle) the memory backing the
packet, after calling this function.
(I'm open to other naming suggestions)
+ unsigned int metasize;
+ unsigned int datasize;
+ unsigned int headroom;
+ struct sk_buff *skb;
+ unsigned int len;
+
+ /* this include metasize */
+ datasize = xdp->data_end - xdp->data_meta;
+ metasize = xdp->data - xdp->data_meta;
+ headroom = xdp->data_meta - xdp->data_hard_start;
+ len = xdp->data_end - xdp->data_hard_start;
+
+ /* allocate a skb to store the frags */
+ skb = __napi_alloc_skb(napi, len, GFP_ATOMIC | __GFP_NOWARN);
+ if (unlikely(!skb))
+ return NULL;
+
+ skb_reserve(skb, headroom);
+ memcpy(__skb_put(skb, datasize), xdp->data_meta, datasize);
+ if (metasize) {
+ __skb_pull(skb, metasize);
+ skb_metadata_set(skb, metasize);
+ }
+
+ return skb;
+}
