From: Eric Dumazet Date: Thu, 4 Jun 2026 14:13:39 +0000 (+0000) Subject: bridge: provide lockless access to p->designated_port X-Git-Url: http://git.ipfire.org/gitweb/?a=commitdiff_plain;h=009b1dc8bf64a8a5ec73a99fc8294523b671a883;p=thirdparty%2Flinux.git bridge: provide lockless access to p->designated_port Add READ_ONCE()/WRITE_ONCE() annotations around p->designated_port This is needed at least for sysfs show_designated_port(), BRCTL_GET_PORT_INFO and upcoming RTNL avoidance in "ip link" dumps (cf br_port_fill_attrs()). Signed-off-by: Eric Dumazet Reviewed-by: Ido Schimmel Acked-by: Nikolay Aleksandrov Link: https://patch.msgid.link/20260604141343.2124500-8-edumazet@google.com Signed-off-by: Jakub Kicinski --- diff --git a/net/bridge/br_ioctl.c b/net/bridge/br_ioctl.c index a507c7b369ac..2be802991f70 100644 --- a/net/bridge/br_ioctl.c +++ b/net/bridge/br_ioctl.c @@ -258,7 +258,7 @@ int br_dev_siocdevprivate(struct net_device *dev, struct ifreq *rq, memcpy(&p.designated_root, &pt->designated_root, 8); memcpy(&p.designated_bridge, &pt->designated_bridge, 8); p.port_id = pt->port_id; - p.designated_port = pt->designated_port; + p.designated_port = READ_ONCE(pt->designated_port); p.path_cost = READ_ONCE(pt->path_cost); p.designated_cost = READ_ONCE(pt->designated_cost); p.state = pt->state; diff --git a/net/bridge/br_netlink.c b/net/bridge/br_netlink.c index 296f62ebdd4a..a722db89aef6 100644 --- a/net/bridge/br_netlink.c +++ b/net/bridge/br_netlink.c @@ -263,7 +263,8 @@ static int br_port_fill_attrs(struct sk_buff *skb, &p->designated_root) || nla_put(skb, IFLA_BRPORT_BRIDGE_ID, sizeof(struct ifla_bridge_id), &p->designated_bridge) || - nla_put_u16(skb, IFLA_BRPORT_DESIGNATED_PORT, p->designated_port) || + nla_put_u16(skb, IFLA_BRPORT_DESIGNATED_PORT, + READ_ONCE(p->designated_port)) || nla_put_u16(skb, IFLA_BRPORT_DESIGNATED_COST, READ_ONCE(p->designated_cost)) || nla_put_u16(skb, IFLA_BRPORT_ID, p->port_id) || diff --git a/net/bridge/br_stp.c b/net/bridge/br_stp.c index ced8d23f05d1..cbc48197c3db 100644 --- a/net/bridge/br_stp.c +++ b/net/bridge/br_stp.c @@ -261,7 +261,7 @@ static void br_record_config_information(struct net_bridge_port *p, p->designated_root = bpdu->root; WRITE_ONCE(p->designated_cost, bpdu->root_path_cost); p->designated_bridge = bpdu->bridge_id; - p->designated_port = bpdu->port_id; + WRITE_ONCE(p->designated_port, bpdu->port_id); p->designated_age = jiffies - bpdu->message_age; mod_timer(&p->message_age_timer, jiffies @@ -434,7 +434,7 @@ void br_become_designated_port(struct net_bridge_port *p) p->designated_root = br->designated_root; WRITE_ONCE(p->designated_cost, br->root_path_cost); p->designated_bridge = br->bridge_id; - p->designated_port = p->port_id; + WRITE_ONCE(p->designated_port, p->port_id); } diff --git a/net/bridge/br_stp_if.c b/net/bridge/br_stp_if.c index e5d43492d2dc..7b0d1a334785 100644 --- a/net/bridge/br_stp_if.c +++ b/net/bridge/br_stp_if.c @@ -320,7 +320,7 @@ int br_stp_set_port_priority(struct net_bridge_port *p, unsigned long newprio) new_port_id = br_make_port_id(newprio, p->port_no); if (br_is_designated_port(p)) - p->designated_port = new_port_id; + WRITE_ONCE(p->designated_port, new_port_id); p->port_id = new_port_id; p->priority = newprio; diff --git a/net/bridge/br_sysfs_if.c b/net/bridge/br_sysfs_if.c index 36b832902d33..1023f97b1c9a 100644 --- a/net/bridge/br_sysfs_if.c +++ b/net/bridge/br_sysfs_if.c @@ -129,7 +129,7 @@ static BRPORT_ATTR(designated_bridge, 0444, show_designated_bridge, NULL); static ssize_t show_designated_port(struct net_bridge_port *p, char *buf) { - return sysfs_emit(buf, "%d\n", p->designated_port); + return sysfs_emit(buf, "%d\n", READ_ONCE(p->designated_port)); } static BRPORT_ATTR(designated_port, 0444, show_designated_port, NULL);