We must ensure the tx descriptor updates are visible before updating
the tx pointer.
This resolves the tx hangs observed on the 2600 when running iperf:
root at ast2600:~# iperf3 -c 192.168.86.146 -R
Connecting to host 192.168.86.146, port 5201
Reverse mode, remote host 192.168.86.146 is sending
[ 5] local 192.168.86.173 port 43886 connected to 192.168.86.146 port 5201
[ ID] Interval Transfer Bitrate
[ 5] 0.00-1.00 sec 90.7 MBytes 760 Mbits/sec
[ 5] 1.00-2.00 sec 91.7 MBytes 769 Mbits/sec
[ 5] 2.00-3.00 sec 91.7 MBytes 770 Mbits/sec
[ 5] 3.00-4.00 sec 91.7 MBytes 769 Mbits/sec
[ 5] 4.00-5.00 sec 91.8 MBytes 771 Mbits/sec
[ 5] 5.00-6.00 sec 91.8 MBytes 771 Mbits/sec
[ 5] 6.00-7.00 sec 91.9 MBytes 771 Mbits/sec
[ 5] 7.00-8.00 sec 91.4 MBytes 767 Mbits/sec
[ 5] 8.00-9.00 sec 91.3 MBytes 766 Mbits/sec
[ 5] 9.00-10.00 sec 91.9 MBytes 771 Mbits/sec
[ 5] 10.00-11.00 sec 91.8 MBytes 770 Mbits/sec
[ 5] 11.00-12.00 sec 91.8 MBytes 770 Mbits/sec
[ 5] 12.00-13.00 sec 90.6 MBytes 761 Mbits/sec
[ 5] 13.00-14.00 sec 45.2 KBytes 370 Kbits/sec
[ 5] 14.00-15.00 sec 0.00 Bytes 0.00 bits/sec
[ 5] 15.00-16.00 sec 0.00 Bytes 0.00 bits/sec
[ 5] 16.00-17.00 sec 0.00 Bytes 0.00 bits/sec
[ 5] 17.00-18.00 sec 0.00 Bytes 0.00 bits/sec
[ 67.031671] ------------[ cut here ]------------
[ 67.036870] WARNING: CPU: 1 PID: 0 at net/sched/sch_generic.c:442 dev_watchdog+0x2dc/0x300
[ 67.046123] NETDEV WATCHDOG: eth2 (ftgmac100): transmit queue 0 timed out
Fixes: 52c0cae87465 ("ftgmac100: Remove tx descriptor accessors")
Signed-off-by: Joel Stanley <joel at jms.id.au>
---
drivers/net/ethernet/faraday/ftgmac100.c | 10 ++++++++++
1 file changed, 10 insertions(+)
diff --git a/drivers/net/ethernet/faraday/ftgmac100.c b/drivers/net/ethernet/faraday/ftgmac100.c
index 331d4bdd4a67..15cdfeb135b0 100644
--- a/drivers/net/ethernet/faraday/ftgmac100.c
+++ b/drivers/net/ethernet/faraday/ftgmac100.c
@@ -653,6 +653,11 @@ static bool ftgmac100_tx_complete_packet(struct ftgmac100 *priv)
ftgmac100_free_tx_packet(priv, pointer, skb, txdes, ctl_stat);
txdes->txdes0 = cpu_to_le32(ctl_stat & priv->txdes0_edotr_mask);
+ /* Ensure the descriptor config is visible before setting the tx
+ * pointer.
+ */
+ smp_wmb();
+
priv->tx_clean_pointer = ftgmac100_next_tx_pointer(priv, pointer);
return true;
@@ -806,6 +811,11 @@ static netdev_tx_t ftgmac100_hard_start_xmit(struct sk_buff *skb,
dma_wmb();
first->txdes0 = cpu_to_le32(f_ctl_stat);
+ /* Ensure the descriptor config is visible before setting the tx
+ * pointer.
+ */
+ smp_wmb();
+
/* Update next TX pointer */
priv->tx_pointer = pointer;
--
2.28.0