From fc1ca3348a74a1afaa7ffebc2b2f2cc149e11278 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Tue, 23 Nov 2021 14:56:07 -0800 Subject: [PATCH 1/2] gro: remove rcu_read_lock/rcu_read_unlock from gro_receive handlers All gro_receive() handlers are called from dev_gro_receive() while rcu_read_lock() has been called. There is no point stacking more rcu_read_lock() Signed-off-by: Eric Dumazet Signed-off-by: Jakub Kicinski --- drivers/net/geneve.c | 5 +---- net/8021q/vlan_core.c | 5 +---- net/ethernet/eth.c | 5 +---- net/ipv4/af_inet.c | 12 ++++-------- net/ipv4/fou.c | 12 +++--------- net/ipv4/gre_offload.c | 9 +++------ net/ipv4/udp_offload.c | 2 -- net/ipv6/ip6_offload.c | 6 +----- net/ipv6/udp_offload.c | 2 -- 9 files changed, 14 insertions(+), 44 deletions(-) diff --git a/drivers/net/geneve.c b/drivers/net/geneve.c index 9d26d1b965d2..9caff2e01d19 100644 --- a/drivers/net/geneve.c +++ b/drivers/net/geneve.c @@ -517,18 +517,15 @@ static struct sk_buff *geneve_gro_receive(struct sock *sk, type = gh->proto_type; - rcu_read_lock(); ptype = gro_find_receive_by_type(type); if (!ptype) - goto out_unlock; + goto out; skb_gro_pull(skb, gh_len); skb_gro_postpull_rcsum(skb, gh, gh_len); pp = call_gro_receive(ptype->callbacks.gro_receive, head, skb); flush = 0; -out_unlock: - rcu_read_unlock(); out: skb_gro_flush_final(skb, pp, flush); diff --git a/net/8021q/vlan_core.c b/net/8021q/vlan_core.c index 59bc13b5f14f..534eebb5a2e6 100644 --- a/net/8021q/vlan_core.c +++ b/net/8021q/vlan_core.c @@ -476,10 +476,9 @@ static struct sk_buff *vlan_gro_receive(struct list_head *head, type = vhdr->h_vlan_encapsulated_proto; - rcu_read_lock(); ptype = gro_find_receive_by_type(type); if (!ptype) - goto out_unlock; + goto out; flush = 0; @@ -501,8 +500,6 @@ static struct sk_buff *vlan_gro_receive(struct list_head *head, ipv6_gro_receive, inet_gro_receive, head, skb); -out_unlock: - rcu_read_unlock(); out: skb_gro_flush_final(skb, pp, flush); diff --git a/net/ethernet/eth.c b/net/ethernet/eth.c index c7d9e08107cb..d4fa2f152efc 100644 --- a/net/ethernet/eth.c +++ b/net/ethernet/eth.c @@ -436,11 +436,10 @@ struct sk_buff *eth_gro_receive(struct list_head *head, struct sk_buff *skb) type = eh->h_proto; - rcu_read_lock(); ptype = gro_find_receive_by_type(type); if (ptype == NULL) { flush = 1; - goto out_unlock; + goto out; } skb_gro_pull(skb, sizeof(*eh)); @@ -450,8 +449,6 @@ struct sk_buff *eth_gro_receive(struct list_head *head, struct sk_buff *skb) ipv6_gro_receive, inet_gro_receive, head, skb); -out_unlock: - rcu_read_unlock(); out: skb_gro_flush_final(skb, pp, flush); diff --git a/net/ipv4/af_inet.c b/net/ipv4/af_inet.c index aa8d15b1e2a4..de7d3a6748f5 100644 --- a/net/ipv4/af_inet.c +++ b/net/ipv4/af_inet.c @@ -1452,19 +1452,18 @@ struct sk_buff *inet_gro_receive(struct list_head *head, struct sk_buff *skb) proto = iph->protocol; - rcu_read_lock(); ops = rcu_dereference(inet_offloads[proto]); if (!ops || !ops->callbacks.gro_receive) - goto out_unlock; + goto out; if (*(u8 *)iph != 0x45) - goto out_unlock; + goto out; if (ip_is_fragment(iph)) - goto out_unlock; + goto out; if (unlikely(ip_fast_csum((u8 *)iph, 5))) - goto out_unlock; + goto out; id = ntohl(*(__be32 *)&iph->id); flush = (u16)((ntohl(*(__be32 *)iph) ^ skb_gro_len(skb)) | (id & ~IP_DF)); @@ -1541,9 +1540,6 @@ struct sk_buff *inet_gro_receive(struct list_head *head, struct sk_buff *skb) pp = indirect_call_gro_receive(tcp4_gro_receive, udp4_gro_receive, ops->callbacks.gro_receive, head, skb); -out_unlock: - rcu_read_unlock(); - out: skb_gro_flush_final(skb, pp, flush); diff --git a/net/ipv4/fou.c b/net/ipv4/fou.c index b56d6b40c0a2..6ebc345e6001 100644 --- a/net/ipv4/fou.c +++ b/net/ipv4/fou.c @@ -247,17 +247,14 @@ static struct sk_buff *fou_gro_receive(struct sock *sk, /* Flag this frame as already having an outer encap header */ NAPI_GRO_CB(skb)->is_fou = 1; - rcu_read_lock(); offloads = NAPI_GRO_CB(skb)->is_ipv6 ? inet6_offloads : inet_offloads; ops = rcu_dereference(offloads[proto]); if (!ops || !ops->callbacks.gro_receive) - goto out_unlock; + goto out; pp = call_gro_receive(ops->callbacks.gro_receive, head, skb); -out_unlock: - rcu_read_unlock(); - +out: return pp; } @@ -439,17 +436,14 @@ static struct sk_buff *gue_gro_receive(struct sock *sk, /* Flag this frame as already having an outer encap header */ NAPI_GRO_CB(skb)->is_fou = 1; - rcu_read_lock(); offloads = NAPI_GRO_CB(skb)->is_ipv6 ? inet6_offloads : inet_offloads; ops = rcu_dereference(offloads[proto]); if (WARN_ON_ONCE(!ops || !ops->callbacks.gro_receive)) - goto out_unlock; + goto out; pp = call_gro_receive(ops->callbacks.gro_receive, head, skb); flush = 0; -out_unlock: - rcu_read_unlock(); out: skb_gro_flush_final_remcsum(skb, pp, flush, &grc); diff --git a/net/ipv4/gre_offload.c b/net/ipv4/gre_offload.c index 740298dac7d3..c6b5d327e3e1 100644 --- a/net/ipv4/gre_offload.c +++ b/net/ipv4/gre_offload.c @@ -163,10 +163,9 @@ static struct sk_buff *gre_gro_receive(struct list_head *head, type = greh->protocol; - rcu_read_lock(); ptype = gro_find_receive_by_type(type); if (!ptype) - goto out_unlock; + goto out; grehlen = GRE_HEADER_SECTION; @@ -180,13 +179,13 @@ static struct sk_buff *gre_gro_receive(struct list_head *head, if (skb_gro_header_hard(skb, hlen)) { greh = skb_gro_header_slow(skb, hlen, off); if (unlikely(!greh)) - goto out_unlock; + goto out; } /* Don't bother verifying checksum if we're going to flush anyway. */ if ((greh->flags & GRE_CSUM) && !NAPI_GRO_CB(skb)->flush) { if (skb_gro_checksum_simple_validate(skb)) - goto out_unlock; + goto out; skb_gro_checksum_try_convert(skb, IPPROTO_GRE, null_compute_pseudo); @@ -230,8 +229,6 @@ static struct sk_buff *gre_gro_receive(struct list_head *head, pp = call_gro_receive(ptype->callbacks.gro_receive, head, skb); flush = 0; -out_unlock: - rcu_read_unlock(); out: skb_gro_flush_final(skb, pp, flush); diff --git a/net/ipv4/udp_offload.c b/net/ipv4/udp_offload.c index cbeb8965d1b7..3be5c083879d 100644 --- a/net/ipv4/udp_offload.c +++ b/net/ipv4/udp_offload.c @@ -628,13 +628,11 @@ struct sk_buff *udp4_gro_receive(struct list_head *head, struct sk_buff *skb) inet_gro_compute_pseudo); skip: NAPI_GRO_CB(skb)->is_ipv6 = 0; - rcu_read_lock(); if (static_branch_unlikely(&udp_encap_needed_key)) sk = udp4_gro_lookup_skb(skb, uh->source, uh->dest); pp = udp_gro_receive(head, skb, uh, sk); - rcu_read_unlock(); return pp; flush: diff --git a/net/ipv6/ip6_offload.c b/net/ipv6/ip6_offload.c index 1b9827ff8ccf..67b9ba5e159c 100644 --- a/net/ipv6/ip6_offload.c +++ b/net/ipv6/ip6_offload.c @@ -208,7 +208,6 @@ INDIRECT_CALLABLE_SCOPE struct sk_buff *ipv6_gro_receive(struct list_head *head, flush += ntohs(iph->payload_len) != skb_gro_len(skb); - rcu_read_lock(); proto = iph->nexthdr; ops = rcu_dereference(inet6_offloads[proto]); if (!ops || !ops->callbacks.gro_receive) { @@ -221,7 +220,7 @@ INDIRECT_CALLABLE_SCOPE struct sk_buff *ipv6_gro_receive(struct list_head *head, ops = rcu_dereference(inet6_offloads[proto]); if (!ops || !ops->callbacks.gro_receive) - goto out_unlock; + goto out; iph = ipv6_hdr(skb); } @@ -279,9 +278,6 @@ INDIRECT_CALLABLE_SCOPE struct sk_buff *ipv6_gro_receive(struct list_head *head, pp = indirect_call_gro_receive_l4(tcp6_gro_receive, udp6_gro_receive, ops->callbacks.gro_receive, head, skb); -out_unlock: - rcu_read_unlock(); - out: skb_gro_flush_final(skb, pp, flush); diff --git a/net/ipv6/udp_offload.c b/net/ipv6/udp_offload.c index 50a8a65fad23..7720d04ed396 100644 --- a/net/ipv6/udp_offload.c +++ b/net/ipv6/udp_offload.c @@ -145,13 +145,11 @@ struct sk_buff *udp6_gro_receive(struct list_head *head, struct sk_buff *skb) skip: NAPI_GRO_CB(skb)->is_ipv6 = 1; - rcu_read_lock(); if (static_branch_unlikely(&udpv6_encap_needed_key)) sk = udp6_gro_lookup_skb(skb, uh->source, uh->dest); pp = udp_gro_receive(head, skb, uh, sk); - rcu_read_unlock(); return pp; flush: From 627b94f75b82d13d1530b59155a545fd99d807db Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Tue, 23 Nov 2021 14:56:08 -0800 Subject: [PATCH 2/2] gro: remove rcu_read_lock/rcu_read_unlock from gro_complete handlers All gro_complete() handlers are called from napi_gro_complete() while rcu_read_lock() has been called. There is no point stacking more rcu_read_lock() Signed-off-by: Eric Dumazet Signed-off-by: Jakub Kicinski --- drivers/net/geneve.c | 3 --- net/8021q/vlan_core.c | 2 -- net/ethernet/eth.c | 2 -- net/ipv4/af_inet.c | 7 ++----- net/ipv4/fou.c | 13 ++++--------- net/ipv4/gre_offload.c | 3 --- net/ipv4/udp_offload.c | 2 -- net/ipv6/ip6_offload.c | 8 ++------ 8 files changed, 8 insertions(+), 32 deletions(-) diff --git a/drivers/net/geneve.c b/drivers/net/geneve.c index 9caff2e01d19..c1fdd721a730 100644 --- a/drivers/net/geneve.c +++ b/drivers/net/geneve.c @@ -545,13 +545,10 @@ static int geneve_gro_complete(struct sock *sk, struct sk_buff *skb, gh_len = geneve_hlen(gh); type = gh->proto_type; - rcu_read_lock(); ptype = gro_find_complete_by_type(type); if (ptype) err = ptype->callbacks.gro_complete(skb, nhoff + gh_len); - rcu_read_unlock(); - skb_set_inner_mac_header(skb, nhoff + gh_len); return err; diff --git a/net/8021q/vlan_core.c b/net/8021q/vlan_core.c index 534eebb5a2e6..acf8c791f320 100644 --- a/net/8021q/vlan_core.c +++ b/net/8021q/vlan_core.c @@ -513,14 +513,12 @@ static int vlan_gro_complete(struct sk_buff *skb, int nhoff) struct packet_offload *ptype; int err = -ENOENT; - rcu_read_lock(); ptype = gro_find_complete_by_type(type); if (ptype) err = INDIRECT_CALL_INET(ptype->callbacks.gro_complete, ipv6_gro_complete, inet_gro_complete, skb, nhoff + sizeof(*vhdr)); - rcu_read_unlock(); return err; } diff --git a/net/ethernet/eth.c b/net/ethernet/eth.c index d4fa2f152efc..ebcc812735a4 100644 --- a/net/ethernet/eth.c +++ b/net/ethernet/eth.c @@ -466,14 +466,12 @@ int eth_gro_complete(struct sk_buff *skb, int nhoff) if (skb->encapsulation) skb_set_inner_mac_header(skb, nhoff); - rcu_read_lock(); ptype = gro_find_complete_by_type(type); if (ptype != NULL) err = INDIRECT_CALL_INET(ptype->callbacks.gro_complete, ipv6_gro_complete, inet_gro_complete, skb, nhoff + sizeof(*eh)); - rcu_read_unlock(); return err; } EXPORT_SYMBOL(eth_gro_complete); diff --git a/net/ipv4/af_inet.c b/net/ipv4/af_inet.c index de7d3a6748f5..04067b249bf3 100644 --- a/net/ipv4/af_inet.c +++ b/net/ipv4/af_inet.c @@ -1612,10 +1612,9 @@ int inet_gro_complete(struct sk_buff *skb, int nhoff) csum_replace2(&iph->check, iph->tot_len, newlen); iph->tot_len = newlen; - rcu_read_lock(); ops = rcu_dereference(inet_offloads[proto]); if (WARN_ON(!ops || !ops->callbacks.gro_complete)) - goto out_unlock; + goto out; /* Only need to add sizeof(*iph) to get to the next hdr below * because any hdr with option will have been flushed in @@ -1625,9 +1624,7 @@ int inet_gro_complete(struct sk_buff *skb, int nhoff) tcp4_gro_complete, udp4_gro_complete, skb, nhoff + sizeof(*iph)); -out_unlock: - rcu_read_unlock(); - +out: return err; } diff --git a/net/ipv4/fou.c b/net/ipv4/fou.c index 6ebc345e6001..0d085cc8d96c 100644 --- a/net/ipv4/fou.c +++ b/net/ipv4/fou.c @@ -266,19 +266,16 @@ static int fou_gro_complete(struct sock *sk, struct sk_buff *skb, const struct net_offload *ops; int err = -ENOSYS; - rcu_read_lock(); offloads = NAPI_GRO_CB(skb)->is_ipv6 ? inet6_offloads : inet_offloads; ops = rcu_dereference(offloads[proto]); if (WARN_ON(!ops || !ops->callbacks.gro_complete)) - goto out_unlock; + goto out; err = ops->callbacks.gro_complete(skb, nhoff); skb_set_inner_mac_header(skb, nhoff); -out_unlock: - rcu_read_unlock(); - +out: return err; } @@ -480,18 +477,16 @@ static int gue_gro_complete(struct sock *sk, struct sk_buff *skb, int nhoff) return err; } - rcu_read_lock(); offloads = NAPI_GRO_CB(skb)->is_ipv6 ? inet6_offloads : inet_offloads; ops = rcu_dereference(offloads[proto]); if (WARN_ON(!ops || !ops->callbacks.gro_complete)) - goto out_unlock; + goto out; err = ops->callbacks.gro_complete(skb, nhoff + guehlen); skb_set_inner_mac_header(skb, nhoff + guehlen); -out_unlock: - rcu_read_unlock(); +out: return err; } diff --git a/net/ipv4/gre_offload.c b/net/ipv4/gre_offload.c index c6b5d327e3e1..07073fa35205 100644 --- a/net/ipv4/gre_offload.c +++ b/net/ipv4/gre_offload.c @@ -253,13 +253,10 @@ static int gre_gro_complete(struct sk_buff *skb, int nhoff) if (greh->flags & GRE_CSUM) grehlen += GRE_HEADER_SECTION; - rcu_read_lock(); ptype = gro_find_complete_by_type(type); if (ptype) err = ptype->callbacks.gro_complete(skb, nhoff + grehlen); - rcu_read_unlock(); - skb_set_inner_mac_header(skb, nhoff + grehlen); return err; diff --git a/net/ipv4/udp_offload.c b/net/ipv4/udp_offload.c index 3be5c083879d..6d1a4bec2614 100644 --- a/net/ipv4/udp_offload.c +++ b/net/ipv4/udp_offload.c @@ -667,7 +667,6 @@ int udp_gro_complete(struct sk_buff *skb, int nhoff, uh->len = newlen; - rcu_read_lock(); sk = INDIRECT_CALL_INET(lookup, udp6_lib_lookup_skb, udp4_lib_lookup_skb, skb, uh->source, uh->dest); if (sk && udp_sk(sk)->gro_complete) { @@ -688,7 +687,6 @@ int udp_gro_complete(struct sk_buff *skb, int nhoff, } else { err = udp_gro_complete_segment(skb); } - rcu_read_unlock(); if (skb->remcsum_offload) skb_shinfo(skb)->gso_type |= SKB_GSO_TUNNEL_REMCSUM; diff --git a/net/ipv6/ip6_offload.c b/net/ipv6/ip6_offload.c index 67b9ba5e159c..48674888f2dc 100644 --- a/net/ipv6/ip6_offload.c +++ b/net/ipv6/ip6_offload.c @@ -327,18 +327,14 @@ INDIRECT_CALLABLE_SCOPE int ipv6_gro_complete(struct sk_buff *skb, int nhoff) iph->payload_len = htons(skb->len - nhoff - sizeof(*iph)); - rcu_read_lock(); - nhoff += sizeof(*iph) + ipv6_exthdrs_len(iph, &ops); if (WARN_ON(!ops || !ops->callbacks.gro_complete)) - goto out_unlock; + goto out; err = INDIRECT_CALL_L4(ops->callbacks.gro_complete, tcp6_gro_complete, udp6_gro_complete, skb, nhoff); -out_unlock: - rcu_read_unlock(); - +out: return err; }