From 81390d0c4e56ac7752c97d7e8209357673d1a8ab Mon Sep 17 00:00:00 2001 From: Taehee Yoo Date: Fri, 28 Feb 2020 18:01:56 +0000 Subject: [PATCH] hsr: remove unnecessary rcu_read_lock() in hsr module In order to access the port list, the hsr_port_get_hsr() is used. And this is protected by RTNL and RCU. The hsr_fill_info(), hsr_check_carrier(), hsr_dev_open() and hsr_get_max_mtu() are protected by RTNL. So, rcu_read_lock() in these functions are not necessary. The hsr_handle_frame() also uses rcu_read_lock() but this function is called by packet path. It's already protected by RCU. So, the rcu_read_lock() in hsr_handle_frame() can be removed. Signed-off-by: Taehee Yoo Signed-off-by: David S. Miller --- net/hsr/hsr_device.c | 23 +++++++---------------- net/hsr/hsr_netlink.c | 27 +++++++++------------------ net/hsr/hsr_slave.c | 3 --- 3 files changed, 16 insertions(+), 37 deletions(-) diff --git a/net/hsr/hsr_device.c b/net/hsr/hsr_device.c index a48f621..00532d1 100644 --- a/net/hsr/hsr_device.c +++ b/net/hsr/hsr_device.c @@ -57,24 +57,19 @@ static void hsr_set_operstate(struct hsr_port *master, bool has_carrier) static bool hsr_check_carrier(struct hsr_port *master) { struct hsr_port *port; - bool has_carrier; - has_carrier = false; + ASSERT_RTNL(); - rcu_read_lock(); - hsr_for_each_port(master->hsr, port) + hsr_for_each_port(master->hsr, port) { if (port->type != HSR_PT_MASTER && is_slave_up(port->dev)) { - has_carrier = true; - break; + netif_carrier_on(master->dev); + return true; } - rcu_read_unlock(); + } - if (has_carrier) - netif_carrier_on(master->dev); - else - netif_carrier_off(master->dev); + netif_carrier_off(master->dev); - return has_carrier; + return false; } static void hsr_check_announce(struct net_device *hsr_dev, @@ -118,11 +113,9 @@ int hsr_get_max_mtu(struct hsr_priv *hsr) struct hsr_port *port; mtu_max = ETH_DATA_LEN; - rcu_read_lock(); hsr_for_each_port(hsr, port) if (port->type != HSR_PT_MASTER) mtu_max = min(port->dev->mtu, mtu_max); - rcu_read_unlock(); if (mtu_max < HSR_HLEN) return 0; @@ -157,7 +150,6 @@ static int hsr_dev_open(struct net_device *dev) hsr = netdev_priv(dev); designation = '\0'; - rcu_read_lock(); hsr_for_each_port(hsr, port) { if (port->type == HSR_PT_MASTER) continue; @@ -175,7 +167,6 @@ static int hsr_dev_open(struct net_device *dev) netdev_warn(dev, "Slave %c (%s) is not up; please bring it up to get a fully working HSR network\n", designation, port->dev->name); } - rcu_read_unlock(); if (designation == '\0') netdev_warn(dev, "No slave devices configured\n"); diff --git a/net/hsr/hsr_netlink.c b/net/hsr/hsr_netlink.c index 7ed308a..64d39c1 100644 --- a/net/hsr/hsr_netlink.c +++ b/net/hsr/hsr_netlink.c @@ -79,29 +79,20 @@ static int hsr_newlink(struct net *src_net, struct net_device *dev, static int hsr_fill_info(struct sk_buff *skb, const struct net_device *dev) { - struct hsr_priv *hsr; + struct hsr_priv *hsr = netdev_priv(dev); struct hsr_port *port; - int res; - - hsr = netdev_priv(dev); - - res = 0; - rcu_read_lock(); port = hsr_port_get_hsr(hsr, HSR_PT_SLAVE_A); - if (port) - res = nla_put_u32(skb, IFLA_HSR_SLAVE1, port->dev->ifindex); - rcu_read_unlock(); - if (res) - goto nla_put_failure; + if (port) { + if (nla_put_u32(skb, IFLA_HSR_SLAVE1, port->dev->ifindex)) + goto nla_put_failure; + } - rcu_read_lock(); port = hsr_port_get_hsr(hsr, HSR_PT_SLAVE_B); - if (port) - res = nla_put_u32(skb, IFLA_HSR_SLAVE2, port->dev->ifindex); - rcu_read_unlock(); - if (res) - goto nla_put_failure; + if (port) { + if (nla_put_u32(skb, IFLA_HSR_SLAVE2, port->dev->ifindex)) + goto nla_put_failure; + } if (nla_put(skb, IFLA_HSR_SUPERVISION_ADDR, ETH_ALEN, hsr->sup_multicast_addr) || diff --git a/net/hsr/hsr_slave.c b/net/hsr/hsr_slave.c index 127ebcc..07edc7f 100644 --- a/net/hsr/hsr_slave.c +++ b/net/hsr/hsr_slave.c @@ -25,7 +25,6 @@ static rx_handler_result_t hsr_handle_frame(struct sk_buff **pskb) return RX_HANDLER_PASS; } - rcu_read_lock(); /* hsr->node_db, hsr->ports */ port = hsr_port_get_rcu(skb->dev); if (!port) goto finish_pass; @@ -45,11 +44,9 @@ static rx_handler_result_t hsr_handle_frame(struct sk_buff **pskb) hsr_forward_skb(skb, port); finish_consume: - rcu_read_unlock(); /* hsr->node_db, hsr->ports */ return RX_HANDLER_CONSUMED; finish_pass: - rcu_read_unlock(); /* hsr->node_db, hsr->ports */ return RX_HANDLER_PASS; } -- 2.7.4