From c7583e9f768eeb82f2531c8372584ba89cfade8b Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Fri, 1 Mar 2024 19:37:39 +0000 Subject: [PATCH] net: gro: enable fast path for more cases Currently the so-called GRO fast path is only enabled for napi_frags_skb() callers. After the prior patch, we no longer have to clear frag0 whenever we pulled bytes to skb->head. We therefore can initialize frag0 to skb->data so that GRO fast path can be used in the following additional cases: - Drivers using header split (populating skb->data with headers, and having payload in one or more page fragments). - Drivers not using any page frag (entire packet is in skb->data) Add a likely() in skb_gro_may_pull() to help the compiler to generate better code if possible. Signed-off-by: Eric Dumazet Acked-by: Paolo Abeni Signed-off-by: Paolo Abeni --- include/net/gro.h | 2 +- net/core/gro.c | 23 ++++++++++++++++------- 2 files changed, 17 insertions(+), 8 deletions(-) diff --git a/include/net/gro.h b/include/net/gro.h index 3c3666e46b30..2b58671a6549 100644 --- a/include/net/gro.h +++ b/include/net/gro.h @@ -148,7 +148,7 @@ static inline void *skb_gro_header_fast(const struct sk_buff *skb, static inline bool skb_gro_may_pull(const struct sk_buff *skb, unsigned int hlen) { - return hlen <= NAPI_GRO_CB(skb)->frag0_len; + return likely(hlen <= NAPI_GRO_CB(skb)->frag0_len); } static inline void *skb_gro_header_slow(struct sk_buff *skb, unsigned int hlen, diff --git a/net/core/gro.c b/net/core/gro.c index 927ccf681490..6a0edbd826a1 100644 --- a/net/core/gro.c +++ b/net/core/gro.c @@ -369,15 +369,21 @@ static void gro_list_prepare(const struct list_head *head, static inline void skb_gro_reset_offset(struct sk_buff *skb, u32 nhoff) { - const struct skb_shared_info *pinfo = skb_shinfo(skb); - const skb_frag_t *frag0 = &pinfo->frags[0]; + const struct skb_shared_info *pinfo; + const skb_frag_t *frag0; + unsigned int headlen; NAPI_GRO_CB(skb)->data_offset = 0; - NAPI_GRO_CB(skb)->frag0 = NULL; - NAPI_GRO_CB(skb)->frag0_len = 0; + headlen = skb_headlen(skb); + NAPI_GRO_CB(skb)->frag0 = skb->data; + NAPI_GRO_CB(skb)->frag0_len = headlen; + if (headlen) + return; - if (!skb_headlen(skb) && pinfo->nr_frags && - !PageHighMem(skb_frag_page(frag0)) && + pinfo = skb_shinfo(skb); + frag0 = &pinfo->frags[0]; + + if (pinfo->nr_frags && !PageHighMem(skb_frag_page(frag0)) && (!NET_IP_ALIGN || !((skb_frag_off(frag0) + nhoff) & 3))) { NAPI_GRO_CB(skb)->frag0 = skb_frag_address(frag0); NAPI_GRO_CB(skb)->frag0_len = min_t(unsigned int, @@ -710,7 +716,10 @@ static struct sk_buff *napi_frags_skb(struct napi_struct *napi) } } else { eth = (const struct ethhdr *)skb->data; - gro_pull_from_frag0(skb, hlen); + + if (NAPI_GRO_CB(skb)->frag0 != skb->data) + gro_pull_from_frag0(skb, hlen); + NAPI_GRO_CB(skb)->frag0 += hlen; NAPI_GRO_CB(skb)->frag0_len -= hlen; }