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authorJosh Bleecher Snyder <josh@tailscale.com>2020-12-15 17:44:21 -0800
committerJason A. Donenfeld <Jason@zx2c4.com>2021-01-07 14:49:44 +0100
commitf7bbdc31a0065e3d5a68a3e6c7a7449954fdd339 (patch)
treeb2605ff0dd0a12be4055d8b936abdb666a88ae9a /device/device.go
parent70861686d3005de91b45d38e5b16fd3132a4a872 (diff)
device: fix data race in peer.timersActive
Found by the race detector and existing tests. To avoid introducing a lock into this hot path, calculate and cache whether any peers exist. Signed-off-by: Josh Bleecher Snyder <josh@tailscale.com>
Diffstat (limited to 'device/device.go')
-rw-r--r--device/device.go6
1 files changed, 4 insertions, 2 deletions
diff --git a/device/device.go b/device/device.go
index 99f5e60..e7d70c4 100644
--- a/device/device.go
+++ b/device/device.go
@@ -49,8 +49,9 @@ type Device struct {
}
peers struct {
- sync.RWMutex
- keyMap map[NoisePublicKey]*Peer
+ empty AtomicBool // empty reports whether len(keyMap) == 0
+ sync.RWMutex // protects keyMap
+ keyMap map[NoisePublicKey]*Peer
}
// unprotected / "self-synchronising resources"
@@ -129,6 +130,7 @@ func unsafeRemovePeer(device *Device, peer *Peer, key NoisePublicKey) {
// remove from peer map
delete(device.peers.keyMap, key)
+ device.peers.empty.Set(len(device.peers.keyMap) == 0)
}
func deviceUpdateState(device *Device) {