From 30a4616c1bfd121ecd7e4325aebd6621e0af719f Mon Sep 17 00:00:00 2001 From: Xin Long Date: Tue, 2 Jul 2019 00:54:55 +0800 Subject: [PATCH] tipc: use rcu dereference functions properly For these places are protected by rcu_read_lock, we change from rcu_dereference_rtnl to rcu_dereference, as there is no need to check if rtnl lock is held. For these places are protected by rtnl_lock, we change from rcu_dereference_rtnl to rtnl_dereference/rcu_dereference_protected, as no extra memory barriers are needed under rtnl_lock() which also protects tn->bearer_list[] and dev->tipc_ptr/b->media_ptr updating. rcu_dereference_rtnl will be only used in the places where it could be under rcu_read_lock or rtnl_lock. Signed-off-by: Xin Long Signed-off-by: David S. Miller --- net/tipc/bearer.c | 14 +++++++------- net/tipc/udp_media.c | 8 ++++---- 2 files changed, 11 insertions(+), 11 deletions(-) diff --git a/net/tipc/bearer.c b/net/tipc/bearer.c index 2bed6589f41e..a809c0ec8d15 100644 --- a/net/tipc/bearer.c +++ b/net/tipc/bearer.c @@ -62,7 +62,7 @@ static struct tipc_bearer *bearer_get(struct net *net, int bearer_id) { struct tipc_net *tn = tipc_net(net); - return rcu_dereference_rtnl(tn->bearer_list[bearer_id]); + return rcu_dereference(tn->bearer_list[bearer_id]); } static void bearer_disable(struct net *net, struct tipc_bearer *b); @@ -210,7 +210,7 @@ void tipc_bearer_add_dest(struct net *net, u32 bearer_id, u32 dest) struct tipc_bearer *b; rcu_read_lock(); - b = rcu_dereference_rtnl(tn->bearer_list[bearer_id]); + b = rcu_dereference(tn->bearer_list[bearer_id]); if (b) tipc_disc_add_dest(b->disc); rcu_read_unlock(); @@ -222,7 +222,7 @@ void tipc_bearer_remove_dest(struct net *net, u32 bearer_id, u32 dest) struct tipc_bearer *b; rcu_read_lock(); - b = rcu_dereference_rtnl(tn->bearer_list[bearer_id]); + b = rcu_dereference(tn->bearer_list[bearer_id]); if (b) tipc_disc_remove_dest(b->disc); rcu_read_unlock(); @@ -444,7 +444,7 @@ int tipc_l2_send_msg(struct net *net, struct sk_buff *skb, struct net_device *dev; int delta; - dev = (struct net_device *)rcu_dereference_rtnl(b->media_ptr); + dev = (struct net_device *)rcu_dereference(b->media_ptr); if (!dev) return 0; @@ -481,7 +481,7 @@ int tipc_bearer_mtu(struct net *net, u32 bearer_id) struct tipc_bearer *b; rcu_read_lock(); - b = rcu_dereference_rtnl(tipc_net(net)->bearer_list[bearer_id]); + b = rcu_dereference(tipc_net(net)->bearer_list[bearer_id]); if (b) mtu = b->mtu; rcu_read_unlock(); @@ -574,8 +574,8 @@ static int tipc_l2_rcv_msg(struct sk_buff *skb, struct net_device *dev, struct tipc_bearer *b; rcu_read_lock(); - b = rcu_dereference_rtnl(dev->tipc_ptr) ?: - rcu_dereference_rtnl(orig_dev->tipc_ptr); + b = rcu_dereference(dev->tipc_ptr) ?: + rcu_dereference(orig_dev->tipc_ptr); if (likely(b && test_bit(0, &b->up) && (skb->pkt_type <= PACKET_MULTICAST))) { skb_mark_not_on_list(skb); diff --git a/net/tipc/udp_media.c b/net/tipc/udp_media.c index c0f694ae57ab..287df68721df 100644 --- a/net/tipc/udp_media.c +++ b/net/tipc/udp_media.c @@ -231,7 +231,7 @@ static int tipc_udp_send_msg(struct net *net, struct sk_buff *skb, } skb_set_inner_protocol(skb, htons(ETH_P_TIPC)); - ub = rcu_dereference_rtnl(b->media_ptr); + ub = rcu_dereference(b->media_ptr); if (!ub) { err = -ENODEV; goto out; @@ -490,7 +490,7 @@ int tipc_udp_nl_dump_remoteip(struct sk_buff *skb, struct netlink_callback *cb) } } - ub = rcu_dereference_rtnl(b->media_ptr); + ub = rtnl_dereference(b->media_ptr); if (!ub) { rtnl_unlock(); return -EINVAL; @@ -532,7 +532,7 @@ int tipc_udp_nl_add_bearer_data(struct tipc_nl_msg *msg, struct tipc_bearer *b) struct udp_bearer *ub; struct nlattr *nest; - ub = rcu_dereference_rtnl(b->media_ptr); + ub = rtnl_dereference(b->media_ptr); if (!ub) return -ENODEV; @@ -806,7 +806,7 @@ static void tipc_udp_disable(struct tipc_bearer *b) { struct udp_bearer *ub; - ub = rcu_dereference_rtnl(b->media_ptr); + ub = rtnl_dereference(b->media_ptr); if (!ub) { pr_err("UDP bearer instance not found\n"); return;