From: Eric Dumazet <edumazet@google.com>
Date: Fri, 1 Apr 2016 15:52:15 +0000 (-0700)
Subject: tcp/dccp: use rcu locking in inet_diag_find_one_icsk()
X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=2d331915a04144dad738e725769d8fac06ef6155;p=linux-beck.git

tcp/dccp: use rcu locking in inet_diag_find_one_icsk()

RX packet processing holds rcu_read_lock(), so we can remove
pairs of rcu_read_lock()/rcu_read_unlock() in lookup functions
if inet_diag also holds rcu before calling them.

This is needed anyway as __inet_lookup_listener() and
inet6_lookup_listener() will soon no longer increment
refcount on the found listener.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
---

diff --git a/net/ipv4/inet_diag.c b/net/ipv4/inet_diag.c
index 5fdb02f5598e..ea8df527b279 100644
--- a/net/ipv4/inet_diag.c
+++ b/net/ipv4/inet_diag.c
@@ -356,6 +356,7 @@ struct sock *inet_diag_find_one_icsk(struct net *net,
 {
 	struct sock *sk;
 
+	rcu_read_lock();
 	if (req->sdiag_family == AF_INET)
 		sk = inet_lookup(net, hashinfo, NULL, 0, req->id.idiag_dst[0],
 				 req->id.idiag_dport, req->id.idiag_src[0],
@@ -376,9 +377,11 @@ struct sock *inet_diag_find_one_icsk(struct net *net,
 					  req->id.idiag_if);
 	}
 #endif
-	else
+	else {
+		rcu_read_unlock();
 		return ERR_PTR(-EINVAL);
-
+	}
+	rcu_read_unlock();
 	if (!sk)
 		return ERR_PTR(-ENOENT);
 
diff --git a/net/ipv4/inet_hashtables.c b/net/ipv4/inet_hashtables.c
index bc68eced0105..387338d71dcd 100644
--- a/net/ipv4/inet_hashtables.c
+++ b/net/ipv4/inet_hashtables.c
@@ -220,7 +220,6 @@ struct sock *__inet_lookup_listener(struct net *net,
 	bool select_ok = true;
 	u32 phash = 0;
 
-	rcu_read_lock();
 begin:
 	result = NULL;
 	hiscore = 0;
@@ -269,7 +268,6 @@ found:
 			goto begin;
 		}
 	}
-	rcu_read_unlock();
 	return result;
 }
 EXPORT_SYMBOL_GPL(__inet_lookup_listener);
@@ -312,7 +310,6 @@ struct sock *__inet_lookup_established(struct net *net,
 	unsigned int slot = hash & hashinfo->ehash_mask;
 	struct inet_ehash_bucket *head = &hashinfo->ehash[slot];
 
-	rcu_read_lock();
 begin:
 	sk_nulls_for_each_rcu(sk, node, &head->chain) {
 		if (sk->sk_hash != hash)
@@ -339,7 +336,6 @@ begin:
 out:
 	sk = NULL;
 found:
-	rcu_read_unlock();
 	return sk;
 }
 EXPORT_SYMBOL_GPL(__inet_lookup_established);
diff --git a/net/ipv6/inet6_hashtables.c b/net/ipv6/inet6_hashtables.c
index d253f32874c9..e6ef6ce1ed74 100644
--- a/net/ipv6/inet6_hashtables.c
+++ b/net/ipv6/inet6_hashtables.c
@@ -69,7 +69,6 @@ struct sock *__inet6_lookup_established(struct net *net,
 	struct inet_ehash_bucket *head = &hashinfo->ehash[slot];
 
 
-	rcu_read_lock();
 begin:
 	sk_nulls_for_each_rcu(sk, node, &head->chain) {
 		if (sk->sk_hash != hash)
@@ -90,7 +89,6 @@ begin:
 out:
 	sk = NULL;
 found:
-	rcu_read_unlock();
 	return sk;
 }
 EXPORT_SYMBOL(__inet6_lookup_established);
@@ -138,7 +136,6 @@ struct sock *inet6_lookup_listener(struct net *net,
 	unsigned int hash = inet_lhashfn(net, hnum);
 	struct inet_listen_hashbucket *ilb = &hashinfo->listening_hash[hash];
 
-	rcu_read_lock();
 begin:
 	result = NULL;
 	hiscore = 0;
@@ -187,7 +184,6 @@ found:
 			goto begin;
 		}
 	}
-	rcu_read_unlock();
 	return result;
 }
 EXPORT_SYMBOL_GPL(inet6_lookup_listener);