On Tue, Oct 15, 2024 at 04:53:44PM +0200, Alexander Lobakin wrote: > The code which builds an skb from an &xdp_buff keeps multiplying itself > around the drivers with almost no changes. Let's try to stop that by > adding a generic function. > There's __xdp_build_skb_from_frame() already, so just convert it to take > &xdp_buff instead, while making the original one a wrapper. The original > one always took an already allocated skb, allow both variants here -- if > no skb passed, which is expected when calling from a driver, pick one via > napi_build_skb(). > > Signed-off-by: Alexander Lobakin <aleksander.lobakin@xxxxxxxxx> > --- > include/net/xdp.h | 1 + > net/core/xdp.c | 55 +++++++++++++++++++++++++++++++++++++++++++++++ > 2 files changed, 56 insertions(+) > > diff --git a/include/net/xdp.h b/include/net/xdp.h > index 19d2b283b845..83e3f4648caa 100644 > --- a/include/net/xdp.h > +++ b/include/net/xdp.h > @@ -330,6 +330,7 @@ xdp_update_skb_shared_info(struct sk_buff *skb, u8 nr_frags, > void xdp_warn(const char *msg, const char *func, const int line); > #define XDP_WARN(msg) xdp_warn(msg, __func__, __LINE__) > > +struct sk_buff *xdp_build_skb_from_buff(const struct xdp_buff *xdp); > struct xdp_frame *xdp_convert_zc_to_xdp_frame(struct xdp_buff *xdp); > struct sk_buff *__xdp_build_skb_from_frame(struct xdp_frame *xdpf, > struct sk_buff *skb, > diff --git a/net/core/xdp.c b/net/core/xdp.c > index b1b426a9b146..9dc103a09b5c 100644 > --- a/net/core/xdp.c > +++ b/net/core/xdp.c > @@ -624,6 +624,61 @@ int xdp_alloc_skb_bulk(void **skbs, int n_skb, gfp_t gfp) > } > EXPORT_SYMBOL_GPL(xdp_alloc_skb_bulk); > > +/** > + * xdp_build_skb_from_buff - create an skb from an &xdp_buff > + * @xdp: &xdp_buff to convert to an skb > + * > + * Perform common operations to create a new skb to pass up the stack from > + * an &xdp_buff: allocate an skb head from the NAPI percpu cache, initialize > + * skb data pointers and offsets, set the recycle bit if the buff is PP-backed, > + * Rx queue index, protocol and update frags info. > + * > + * Return: new &sk_buff on success, %NULL on error. > + */ > +struct sk_buff *xdp_build_skb_from_buff(const struct xdp_buff *xdp) > +{ > + const struct xdp_rxq_info *rxq = xdp->rxq; > + const struct skb_shared_info *sinfo; > + struct sk_buff *skb; > + u32 nr_frags = 0; > + int metalen; > + > + if (unlikely(xdp_buff_has_frags(xdp))) { > + sinfo = xdp_get_shared_info_from_buff(xdp); > + nr_frags = sinfo->nr_frags; > + } > + > + skb = napi_build_skb(xdp->data_hard_start, xdp->frame_sz); > + if (unlikely(!skb)) > + return NULL; > + > + skb_reserve(skb, xdp->data - xdp->data_hard_start); > + __skb_put(skb, xdp->data_end - xdp->data); > + > + metalen = xdp->data - xdp->data_meta; > + if (metalen > 0) > + skb_metadata_set(skb, metalen); > + > + if (is_page_pool_compiled_in() && rxq->mem.type == MEM_TYPE_PAGE_POOL) > + skb_mark_for_recycle(skb); > + > + skb_record_rx_queue(skb, rxq->queue_index); > + > + if (unlikely(nr_frags)) { > + u32 ts; nit: spell out truesize? ts confuse my brain with timestamp TBH > + > + ts = sinfo->xdp_frags_truesize ? : nr_frags * xdp->frame_sz; > + xdp_update_skb_shared_info(skb, nr_frags, > + sinfo->xdp_frags_size, ts, > + xdp_buff_is_frag_pfmemalloc(xdp)); > + } > + > + skb->protocol = eth_type_trans(skb, rxq->dev); could we leave this out to be set by drivers? i see in ice for example netdev ptr is retrieved in different ways here. > + > + return skb; > +} > +EXPORT_SYMBOL_GPL(xdp_build_skb_from_buff); > + > struct sk_buff *__xdp_build_skb_from_frame(struct xdp_frame *xdpf, > struct sk_buff *skb, > struct net_device *dev) > -- > 2.46.2 >