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 <edumazet@google.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

8 files changed, 13 insertions, 40 deletions

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 @@ 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);
 
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 @@ 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);
 
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: