device: clarify device.state.state docs (again)

Signed-off-by: Josh Bleecher Snyder <josh@tailscale.com>
This commit is contained in:
Josh Bleecher Snyder 2021-02-09 08:27:48 -08:00 committed by Jason A. Donenfeld
parent 465261310b
commit cae090d116

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@ -24,8 +24,10 @@ type Device struct {
state struct { state struct {
// state holds the device's state. It is accessed atomically. // state holds the device's state. It is accessed atomically.
// Use the device.deviceState method to read it. // Use the device.deviceState method to read it.
// If state is not locked, state is the current state of the device. // device.deviceState does not acquire the mutex, so it captures only a snapshot.
// If state is locked, state is the current state or intended future state of the device. // During state transitions, the state variable is updated before the device itself.
// The state is thus either the current state of the device or
// the intended future state of the device.
// For example, while executing a call to Up, state will be deviceStateUp. // For example, while executing a call to Up, state will be deviceStateUp.
// There is no guarantee that that intended future state of the device // There is no guarantee that that intended future state of the device
// will become the actual state; Up can fail. // will become the actual state; Up can fail.