Merge branch 'gro-remove-redundant-rcu_read_lock'

Eric Dumazet says:

====================
gro: remove redundant rcu_read_lock

Recent trees got an increase of rcu_read_{lock|unlock} costs,
it is time to get rid of the not needed pairs.
====================

Link: https://lore.kernel.org/r/20211123225608.2155163-1-eric.dumazet@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

9 files changed, 22 insertions, 76 deletions

diff --git a/drivers/net/geneve.c b/drivers/net/geneve.c
index 9d26d1b965d2..c1fdd721a730 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);
 
@@ -548,13 +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 59bc13b5f14f..acf8c791f320 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);
 
@@ -516,14 +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 c7d9e08107cb..ebcc812735a4 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);
 
@@ -469,14 +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 aa8d15b1e2a4..04067b249bf3 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);
 
@@ -1616,10 +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
@@ -1629,9 +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 b56d6b40c0a2..0d085cc8d96c 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;
 }
 
@@ -269,19 +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;
 }
 
@@ -439,17 +433,14 @@ next_proto:
 	/* 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);
 
@@ -486,18 +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 740298dac7d3..07073fa35205 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);
 
@@ -256,13 +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 cbeb8965d1b7..6d1a4bec2614 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:
@@ -669,7 +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) {
@@ -690,7 +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 1b9827ff8ccf..48674888f2dc 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 @@ not_same_flow:
 	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);
 
@@ -331,18 +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;
 }
 
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: