When timestamping received packets, rx_timestamp_work may be scheduled
before the timestamps is received from the hardware resulting in the
packet beeing delivered without the timestamp.
This is fixed by changing the receive timestamp path:
On receiving a packet that need timestamping, the rxts list is
traversed. If a match is found, packet+timestamp are delivered,
otherwise the packet is added to a rx_queue.
When a timestamp arrives rx_queue is traversed and if a matching
packet is found, it is delivered with the timestamp. Otherwise the
timestamp is added to the rxts list for matching with packets arriving
later.
In case the hardware drops a timestamp, a workqueue regularly checks
the queue for old packets and delivers them without a timestamp.
Signed-off-by: Stefan Sørensen <stefan.sorensen@spectralink.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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