diff options
| author | Vedang Patel <vedang.patel@intel.com> | 2019-06-25 15:07:12 -0700 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2019-06-28 14:45:33 -0700 |
| commit | 1e08511d5d01884a3c9070afd52a47799312074a (patch) | |
| tree | ea2cfeaae03de3b7c71c728d65a550d16de9711c /drivers/net/ethernet/intel/igb | |
| parent | 8747d82d3c32df488ea0fe9b86bdb53a8a04a7b8 (diff) | |
igb: clear out skb->tstamp after reading the txtime
If a packet which is utilizing the launchtime feature (via SO_TXTIME socket
option) also requests the hardware transmit timestamp, the hardware
timestamp is not delivered to the userspace. This is because the value in
skb->tstamp is mistaken as the software timestamp.
Applications, like ptp4l, request a hardware timestamp by setting the
SOF_TIMESTAMPING_TX_HARDWARE socket option. Whenever a new timestamp is
detected by the driver (this work is done in igb_ptp_tx_work() which calls
igb_ptp_tx_hwtstamps() in igb_ptp.c[1]), it will queue the timestamp in the
ERR_QUEUE for the userspace to read. When the userspace is ready, it will
issue a recvmsg() call to collect this timestamp. The problem is in this
recvmsg() call. If the skb->tstamp is not cleared out, it will be
interpreted as a software timestamp and the hardware tx timestamp will not
be successfully sent to the userspace. Look at skb_is_swtx_tstamp() and the
callee function __sock_recv_timestamp() in net/socket.c for more details.
Signed-off-by: Vedang Patel <vedang.patel@intel.com>
Tested-by: Aaron Brown <aaron.f.brown@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'drivers/net/ethernet/intel/igb')
| -rw-r--r-- | drivers/net/ethernet/intel/igb/igb_main.c | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/drivers/net/ethernet/intel/igb/igb_main.c b/drivers/net/ethernet/intel/igb/igb_main.c index fc925adbd9fa..f66dae72fe37 100644 --- a/drivers/net/ethernet/intel/igb/igb_main.c +++ b/drivers/net/ethernet/intel/igb/igb_main.c @@ -5688,6 +5688,7 @@ static void igb_tx_ctxtdesc(struct igb_ring *tx_ring, */ if (tx_ring->launchtime_enable) { ts = ns_to_timespec64(first->skb->tstamp); + first->skb->tstamp = 0; context_desc->seqnum_seed = cpu_to_le32(ts.tv_nsec / 32); } else { context_desc->seqnum_seed = 0; |