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Miller" , Jakub Kicinski , Paolo Abeni Cc: Simon Horman , Ido Schimmel , Nikolay Aleksandrov , netdev@vger.kernel.org, eric.dumazet@gmail.com, Eric Dumazet Content-Type: text/plain; charset="UTF-8" Add READ_ONCE()/WRITE_ONCE() annotations around p->designated_cost This is needed at least for sysfs show_designated_cost(), BRCTL_GET_PORT_INFO and upcoming RTNL avoidance in "ip link" dumps (cf br_port_fill_attrs()). Signed-off-by: Eric Dumazet --- net/bridge/br_ioctl.c | 2 +- net/bridge/br_netlink.c | 3 ++- net/bridge/br_stp.c | 28 ++++++++++++++++------------ net/bridge/br_sysfs_if.c | 2 +- 4 files changed, 20 insertions(+), 15 deletions(-) diff --git a/net/bridge/br_ioctl.c b/net/bridge/br_ioctl.c index 07cfcb821e27ebcb72901a365a3f06491f8b0bc3..a507c7b369ac49803019cdca7836c7fb9ef4459e 100644 --- a/net/bridge/br_ioctl.c +++ b/net/bridge/br_ioctl.c @@ -260,7 +260,7 @@ int br_dev_siocdevprivate(struct net_device *dev, struct ifreq *rq, p.port_id = pt->port_id; p.designated_port = pt->designated_port; p.path_cost = READ_ONCE(pt->path_cost); - p.designated_cost = pt->designated_cost; + p.designated_cost = READ_ONCE(pt->designated_cost); p.state = pt->state; p.top_change_ack = pt->topology_change_ack; p.config_pending = pt->config_pending; diff --git a/net/bridge/br_netlink.c b/net/bridge/br_netlink.c index 08718ebe282aa1d089a127cdc7c24fda5a0a38a5..296f62ebdd4a6f3d404b5902fe661995bd1ca0f5 100644 --- a/net/bridge/br_netlink.c +++ b/net/bridge/br_netlink.c @@ -264,7 +264,8 @@ static int br_port_fill_attrs(struct sk_buff *skb, 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_COST, p->designated_cost) || + nla_put_u16(skb, IFLA_BRPORT_DESIGNATED_COST, + READ_ONCE(p->designated_cost)) || nla_put_u16(skb, IFLA_BRPORT_ID, p->port_id) || nla_put_u16(skb, IFLA_BRPORT_NO, p->port_no) || nla_put_u8(skb, IFLA_BRPORT_TOPOLOGY_CHANGE_ACK, diff --git a/net/bridge/br_stp.c b/net/bridge/br_stp.c index 2d9d0823aa56b63a62ed51c49df54055294e82ad..88da86a6ba4406ac77d0b13e0a340e87e281c11a 100644 --- a/net/bridge/br_stp.c +++ b/net/bridge/br_stp.c @@ -102,7 +102,7 @@ struct net_bridge_port *br_get_port(struct net_bridge *br, u16 port_no) static int br_should_become_root_port(const struct net_bridge_port *p, u16 root_port) { - u32 p_path_cost, rp_path_cost; + u32 p_path_cost, rp_path_cost, p_designated_cost, rp_designated_cost; struct net_bridge_port *rp; struct net_bridge *br; int t; @@ -128,12 +128,14 @@ static int br_should_become_root_port(const struct net_bridge_port *p, p_path_cost = READ_ONCE(p->path_cost); rp_path_cost = READ_ONCE(rp->path_cost); + p_designated_cost = READ_ONCE(p->designated_cost); + rp_designated_cost = READ_ONCE(rp->designated_cost); - if (p->designated_cost + p_path_cost < - rp->designated_cost + rp_path_cost) + if (p_designated_cost + p_path_cost < + rp_designated_cost + rp_path_cost) return 1; - else if (p->designated_cost + p_path_cost > - rp->designated_cost + rp_path_cost) + else if (p_designated_cost + p_path_cost > + rp_designated_cost + rp_path_cost) return 0; t = memcmp(&p->designated_bridge, &rp->designated_bridge, 8); @@ -191,7 +193,7 @@ static void br_root_selection(struct net_bridge *br) } else { p = br_get_port(br, root_port); br->designated_root = p->designated_root; - br->root_path_cost = p->designated_cost + + br->root_path_cost = READ_ONCE(p->designated_cost) + READ_ONCE(p->path_cost); } } @@ -257,7 +259,7 @@ static void br_record_config_information(struct net_bridge_port *p, const struct br_config_bpdu *bpdu) { p->designated_root = bpdu->root; - p->designated_cost = bpdu->root_path_cost; + WRITE_ONCE(p->designated_cost, bpdu->root_path_cost); p->designated_bridge = bpdu->bridge_id; p->designated_port = bpdu->port_id; p->designated_age = jiffies - bpdu->message_age; @@ -302,9 +304,10 @@ static int br_should_become_designated_port(const struct net_bridge_port *p) if (memcmp(&p->designated_root, &br->designated_root, 8)) return 1; - if (br->root_path_cost < p->designated_cost) + t = br->root_path_cost - READ_ONCE(p->designated_cost); + if (t < 0) return 1; - else if (br->root_path_cost > p->designated_cost) + else if (t > 0) return 0; t = memcmp(&br->bridge_id, &p->designated_bridge, 8); @@ -344,9 +347,10 @@ static int br_supersedes_port_info(const struct net_bridge_port *p, else if (t > 0) return 0; - if (bpdu->root_path_cost < p->designated_cost) + t = bpdu->root_path_cost < READ_ONCE(p->designated_cost); + if (t < 0) return 1; - else if (bpdu->root_path_cost > p->designated_cost) + else if (t > 0) return 0; t = memcmp(&bpdu->bridge_id, &p->designated_bridge, 8); @@ -426,7 +430,7 @@ void br_become_designated_port(struct net_bridge_port *p) br = p->br; p->designated_root = br->designated_root; - p->designated_cost = br->root_path_cost; + WRITE_ONCE(p->designated_cost, br->root_path_cost); p->designated_bridge = br->bridge_id; p->designated_port = p->port_id; } diff --git a/net/bridge/br_sysfs_if.c b/net/bridge/br_sysfs_if.c index 23574476d7f701080452777ab2c23a42b4defba4..36b832902d33a492e91d53a4248778b3ee2322ca 100644 --- a/net/bridge/br_sysfs_if.c +++ b/net/bridge/br_sysfs_if.c @@ -135,7 +135,7 @@ static BRPORT_ATTR(designated_port, 0444, show_designated_port, NULL); static ssize_t show_designated_cost(struct net_bridge_port *p, char *buf) { - return sysfs_emit(buf, "%d\n", p->designated_cost); + return sysfs_emit(buf, "%d\n", READ_ONCE(p->designated_cost)); } static BRPORT_ATTR(designated_cost, 0444, show_designated_cost, NULL); -- 2.54.0.1013.g208068f2d8-goog