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Date: Fri, 28 Feb 2020 18:01:56 +0000
From: Taehee Yoo <ap420073@...il.com>
To: davem@...emloft.net, kuba@...nel.org, netdev@...r.kernel.org
Cc: ap420073@...il.com
Subject: [PATCH net-next 4/5] 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 <ap420073@...il.com>
---
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 a48f621c2fec..00532d14fc7c 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 7ed308a0c035..64d39c1e93a2 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 127ebcc0e28f..07edc7f626fe 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;
}
--
2.17.1
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