[PATCH v3 net-next 08/11] bridge: provide lockless access to p->priority

[Eric Dumazet <edumazet@google.com>]

sysfs show_priority() needs this.

Also br_port_fill_attrs() might in the future run without RTNL.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Ido Schimmel <idosch@nvidia.com>
Acked-by: Nikolay Aleksandrov <razor@blackwall.org>
---
 net/bridge/br_netlink.c  | 2 +-
 net/bridge/br_stp_if.c   | 2 +-
 net/bridge/br_sysfs_if.c | 2 +-
 3 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/net/bridge/br_netlink.c b/net/bridge/br_netlink.c
index a722db89aef6bbb6ecc77c7e0f173dc79418797f..fc25c6b6cc9713080873976f443da1fbd764aafe 100644
--- a/net/bridge/br_netlink.c
+++ b/net/bridge/br_netlink.c
@@ -239,7 +239,7 @@ static int br_port_fill_attrs(struct sk_buff *skb,
 	u64 timerval;
 
 	if (nla_put_u8(skb, IFLA_BRPORT_STATE, p->state) ||
-	    nla_put_u16(skb, IFLA_BRPORT_PRIORITY, p->priority) ||
+	    nla_put_u16(skb, IFLA_BRPORT_PRIORITY, READ_ONCE(p->priority)) ||
 	    nla_put_u32(skb, IFLA_BRPORT_COST, READ_ONCE(p->path_cost)) ||
 	    nla_put_u8(skb, IFLA_BRPORT_MODE, mode) ||
 	    nla_put_u8(skb, IFLA_BRPORT_GUARD, !!(p->flags & BR_BPDU_GUARD)) ||
diff --git a/net/bridge/br_stp_if.c b/net/bridge/br_stp_if.c
index 7b0d1a334785047905a00694fd65e3212b160e5d..3524bb7e87f0586774a883720be9fa8eb60f0370 100644
--- a/net/bridge/br_stp_if.c
+++ b/net/bridge/br_stp_if.c
@@ -323,7 +323,7 @@ int br_stp_set_port_priority(struct net_bridge_port *p, unsigned long newprio)
 		WRITE_ONCE(p->designated_port, new_port_id);
 
 	p->port_id = new_port_id;
-	p->priority = newprio;
+	WRITE_ONCE(p->priority, newprio);
 	if (!memcmp(&p->br->bridge_id, &p->designated_bridge, 8) &&
 	    p->port_id < p->designated_port) {
 		br_become_designated_port(p);
diff --git a/net/bridge/br_sysfs_if.c b/net/bridge/br_sysfs_if.c
index 1023f97b1c9a22a1f79c3c734aef9bd41832ea39..3f666d4fef42324a4751779153ecc48bdb44b85a 100644
--- a/net/bridge/br_sysfs_if.c
+++ b/net/bridge/br_sysfs_if.c
@@ -100,7 +100,7 @@ static BRPORT_ATTR(path_cost, 0644, show_path_cost, store_path_cost);
 
 static ssize_t show_priority(struct net_bridge_port *p, char *buf)
 {
-	return sysfs_emit(buf, "%d\n", p->priority);
+	return sysfs_emit(buf, "%d\n", READ_ONCE(p->priority));
 }
 
 static int store_priority(struct net_bridge_port *p, unsigned long v)
-- 
2.54.0.1032.g2f8565e1d1-goog