diff options
Diffstat (limited to 'target/linux/generic/backport-5.4/050-gro-fix-napi_gro_frags-Fast-GRO-breakage-due-to-IP-a.patch')
| -rw-r--r-- | target/linux/generic/backport-5.4/050-gro-fix-napi_gro_frags-Fast-GRO-breakage-due-to-IP-a.patch | 75 |
1 files changed, 75 insertions, 0 deletions
diff --git a/target/linux/generic/backport-5.4/050-gro-fix-napi_gro_frags-Fast-GRO-breakage-due-to-IP-a.patch b/target/linux/generic/backport-5.4/050-gro-fix-napi_gro_frags-Fast-GRO-breakage-due-to-IP-a.patch new file mode 100644 index 0000000000..17e9e34589 --- /dev/null +++ b/target/linux/generic/backport-5.4/050-gro-fix-napi_gro_frags-Fast-GRO-breakage-due-to-IP-a.patch @@ -0,0 +1,75 @@ +From 3007b05df4301aad179acc6ca1c3645785576df6 Mon Sep 17 00:00:00 2001 +From: Alexander Lobakin <alobakin@pm.me> +Date: Mon, 19 Apr 2021 12:53:06 +0000 +Subject: gro: fix napi_gro_frags() Fast GRO breakage due to IP + alignment check + +Commit 7ad18ff6449cbd6beb26b53128ddf56d2685aa93 upstream. + +Commit 38ec4944b593 ("gro: ensure frag0 meets IP header alignment") +did the right thing, but missed the fact that napi_gro_frags() logics +calls for skb_gro_reset_offset() *before* pulling Ethernet header +to the skb linear space. +That said, the introduced check for frag0 address being aligned to 4 +always fails for it as Ethernet header is obviously 14 bytes long, +and in case with NET_IP_ALIGN its start is not aligned to 4. + +Fix this by adding @nhoff argument to skb_gro_reset_offset() which +tells if an IP header is placed right at the start of frag0 or not. +This restores Fast GRO for napi_gro_frags() that became very slow +after the mentioned commit, and preserves the introduced check to +avoid silent unaligned accesses. + +From v1 [0]: + - inline tiny skb_gro_reset_offset() to let the code be optimized + more efficively (esp. for the !NET_IP_ALIGN case) (Eric); + - pull in Reviewed-by from Eric. + +[0] https://lore.kernel.org/netdev/20210418114200.5839-1-alobakin@pm.me + +Fixes: 38ec4944b593 ("gro: ensure frag0 meets IP header alignment") +Reviewed-by: Eric Dumazet <edumazet@google.com> +Signed-off-by: Alexander Lobakin <alobakin@pm.me> +Signed-off-by: David S. Miller <davem@davemloft.net> +--- + net/core/dev.c | 8 ++++---- + 1 file changed, 4 insertions(+), 4 deletions(-) + +--- a/net/core/dev.c ++++ b/net/core/dev.c +@@ -5395,7 +5395,7 @@ static struct list_head *gro_list_prepar + return head; + } + +-static void skb_gro_reset_offset(struct sk_buff *skb) ++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]; +@@ -5407,7 +5407,7 @@ static void skb_gro_reset_offset(struct + if (skb_mac_header(skb) == skb_tail_pointer(skb) && + pinfo->nr_frags && + !PageHighMem(skb_frag_page(frag0)) && +- (!NET_IP_ALIGN || !(skb_frag_off(frag0) & 3))) { ++ (!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, + skb_frag_size(frag0), +@@ -5640,7 +5640,7 @@ gro_result_t napi_gro_receive(struct nap + skb_mark_napi_id(skb, napi); + trace_napi_gro_receive_entry(skb); + +- skb_gro_reset_offset(skb); ++ skb_gro_reset_offset(skb, 0); + + ret = napi_skb_finish(napi, skb, dev_gro_receive(napi, skb)); + trace_napi_gro_receive_exit(ret); +@@ -5733,7 +5733,7 @@ static struct sk_buff *napi_frags_skb(st + napi->skb = NULL; + + skb_reset_mac_header(skb); +- skb_gro_reset_offset(skb); ++ skb_gro_reset_offset(skb, hlen); + + if (unlikely(skb_gro_header_hard(skb, hlen))) { + eth = skb_gro_header_slow(skb, hlen, 0); |