| Message ID | 20241015145350.4077765-13-aleksander.lobakin@intel.com (mailing list archive) |
|---|---|
| State | Changes Requested |
| Delegated to: | BPF |
| Headers | show |
| Series | idpf: XDP chapter III: core XDP changes (+libeth_xdp) | expand |
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@intel.com> > --- > 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 >
From: Maciej Fijalkowski <maciej.fijalkowski@intel.com> Date: Thu, 17 Oct 2024 14:34:33 +0200 > 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. [...] >> + 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 Ack. > >> + >> + 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. As for ice, it's for representors only + unlikely() + we could override it manually there later (set skb->dev + call eth_skb_pkt_type()). OTOH this looks more consistent with xdp_build_skb_from_frame() + saves some object code (you won't need to generate a call to eth_type_trans() in each driver). > >> + >> + 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 Thanks, Olek
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; + + 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); + + 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)
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@intel.com> --- include/net/xdp.h | 1 + net/core/xdp.c | 55 +++++++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 56 insertions(+)