| Message ID | 20170207084646.70dc888a@xeon-e3 |
|---|---|
| State | Accepted, archived |
| Delegated to: | David Miller |
| Headers | show |
On 07/02/17 17:46, Stephen Hemminger wrote: > > Jiffies is volatile so read it once. > > Signed-off-by: Stephen Hemminger <sthemmin@microsoft.com> > --- > net/bridge/br_fdb.c | 6 ++++-- > net/bridge/br_input.c | 6 ++++-- > 2 files changed, 8 insertions(+), 4 deletions(-) > Yep, good catch. Maybe you can use READ_ONCE() even though it's not needed just to show why it's done this way. Acked-by: Nikolay Aleksandrov <nikolay@cumulusnetworks.com>
From: Stephen Hemminger <stephen@networkplumber.org> Date: Tue, 7 Feb 2017 08:46:46 -0800 > Jiffies is volatile so read it once. > > Signed-off-by: Stephen Hemminger <sthemmin@microsoft.com> Applied, thanks Stephen.
diff --git a/net/bridge/br_fdb.c b/net/bridge/br_fdb.c index 5028691fa68a..5693168e88b6 100644 --- a/net/bridge/br_fdb.c +++ b/net/bridge/br_fdb.c @@ -592,13 +592,15 @@ void br_fdb_update(struct net_bridge *br, struct net_bridge_port *source, br_warn(br, "received packet on %s with own address as source address (addr:%pM, vlan:%u)\n", source->dev->name, addr, vid); } else { + unsigned long now = jiffies; + /* fastpath: update of existing entry */ if (unlikely(source != fdb->dst)) { fdb->dst = source; fdb_modified = true; } - if (jiffies != fdb->updated) - fdb->updated = jiffies; + if (now != fdb->updated) + fdb->updated = now; if (unlikely(added_by_user)) fdb->added_by_user = 1; if (unlikely(fdb_modified)) diff --git a/net/bridge/br_input.c b/net/bridge/br_input.c index 220943f920d2..4615a9b3e26c 100644 --- a/net/bridge/br_input.c +++ b/net/bridge/br_input.c @@ -195,11 +195,13 @@ int br_handle_frame_finish(struct net *net, struct sock *sk, struct sk_buff *skb } if (dst) { + unsigned long now = jiffies; + if (dst->is_local) return br_pass_frame_up(skb); - if (jiffies != dst->used) - dst->used = jiffies; + if (now != dst->used) + dst->used = now; br_forward(dst->dst, skb, local_rcv, false); } else { if (!mcast_hit)
Jiffies is volatile so read it once. Signed-off-by: Stephen Hemminger <sthemmin@microsoft.com> --- net/bridge/br_fdb.c | 6 ++++-- net/bridge/br_input.c | 6 ++++-- 2 files changed, 8 insertions(+), 4 deletions(-)