Re: [PATCH net] bridge: fix hello and hold timers starting/stopping
From: Nikolay Aleksandrov <hidden>
Date: 2017-05-19 16:55:40
Also in:
bridge
On 5/19/17 7:25 PM, Ivan Vecera wrote:
Current bridge code incorrectly handles starting/stopping of hello and
hold timers during STP enable/disable.
1. Timers are stopped in br_stp_start() during NO_STP->USER_STP
transition. This is not correct as the timers are stopped in NO_STP
case.This really is a noop, but ok.
2. Timers are started in br_stp_stop() during USER_STP->NO_STP transition.
This is not also correct as the timers should be stopped in NO_STP
state.Indeed, but the actual end result is almost as them being stopped because in the timers there are specific checks if the STP == KERNEL_STP (see br_transmit_config()) and the hold_timers will simply expire and not rearm in any other mode. The only real problem is the hello_timer which continues to rearm itself, but with Xin's earlier patch that is taken care of too.
3. Timers are NOT stopped in br_stp_stop() during KERNEL_STP->NO_STP
transition. They should be stopped as they are running in KERNEL_STP
state and should not run in NO_STP case.Same comment as for point 2.
The patch is a follow-up for "bridge: start hello_timer when enabling KERNEL_STP in br_stp_start" patch from Xin Long.
I'd say this is more of a cleanup/improvement after Xin's patch and thus would suggest targeting net-next. The only real issue is fixed by his patch.
quoted hunk ↗ jump to hunk
Cc: davem@davemloft.net Cc: sashok@cumulusnetworks.com Cc: stephen@networkplumber.org Cc: bridge@lists.linux-foundation.org Cc: lucien.xin@gmail.com Cc: nikolay@cumulusnetworks.com Signed-off-by: Ivan Vecera <redacted> --- net/bridge/br_stp_if.c | 15 +++++---------- 1 file changed, 5 insertions(+), 10 deletions(-)diff --git a/net/bridge/br_stp_if.c b/net/bridge/br_stp_if.c index 0db8102995a5..f137ebf27755 100644 --- a/net/bridge/br_stp_if.c +++ b/net/bridge/br_stp_if.c@@ -150,7 +150,6 @@ static int br_stp_call_user(struct net_bridge *br, char *arg) static void br_stp_start(struct net_bridge *br) { - struct net_bridge_port *p; int err = -ENOENT; if (net_eq(dev_net(br->dev), &init_net))@@ -169,11 +168,6 @@ static void br_stp_start(struct net_bridge *br) if (!err) { br->stp_enabled = BR_USER_STP; br_debug(br, "userspace STP started\n"); - - /* Stop hello and hold timers */ - del_timer(&br->hello_timer); - list_for_each_entry(p, &br->port_list, list) - del_timer(&p->hold_timer); } else { br->stp_enabled = BR_KERNEL_STP; br_debug(br, "using kernel STP\n");@@ -197,13 +191,14 @@ static void br_stp_stop(struct net_bridge *br) br_err(br, "failed to stop userspace STP (%d)\n", err); /* To start timers on any ports left in blocking */ - mod_timer(&br->hello_timer, jiffies + br->hello_time); - list_for_each_entry(p, &br->port_list, list) - mod_timer(&p->hold_timer, - round_jiffies(jiffies + BR_HOLD_TIME)); spin_lock_bh(&br->lock); br_port_state_selection(br); spin_unlock_bh(&br->lock); + } else { + /* BR_KERNEL_STP - stop hello and hold timers */ + del_timer(&br->hello_timer); + list_for_each_entry(p, &br->port_list, list) + del_timer(&p->hold_timer); } br->stp_enabled = BR_NO_STP;