target/linux/lantiq/patches-5.4/0010-net-lantiq-Add-locking-for-TX-DMA-channel.patch

   1 From e0c0ad805905d7dc3d6cd36da86119535f0cf374 Mon Sep 17 00:00:00 2001
   2 From: Hauke Mehrtens <hauke@hauke-m.de>
   3 Date: Tue, 22 Sep 2020 23:14:03 +0200
   4 Subject: net: lantiq: Add locking for TX DMA channel
   5
   6 The TX DMA channel data is accessed by the xrx200_start_xmit() and the
   7 xrx200_tx_housekeeping() function from different threads. Make sure the
   8 accesses are synchronized by acquiring the netif_tx_lock() in the
   9 xrx200_tx_housekeeping() function too. This lock is acquired by the
  10 kernel before calling xrx200_start_xmit().
  11
  12 Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>
  13 ---
  14  drivers/net/ethernet/lantiq_xrx200.c | 2 ++
  15  1 file changed, 2 insertions(+)
  16
  17 --- a/drivers/net/ethernet/lantiq_xrx200.c
  18 +++ b/drivers/net/ethernet/lantiq_xrx200.c
  19 @@ -245,6 +245,7 @@ static int xrx200_tx_housekeeping(struct
  20         int pkts = 0;
  21         int bytes = 0;
  22
  23 +       netif_tx_lock(net_dev);
  24         while (pkts < budget) {
  25                 struct ltq_dma_desc *desc = &ch->dma.desc_base[ch->tx_free];
  26
  27 @@ -268,6 +269,7 @@ static int xrx200_tx_housekeeping(struct
  28         net_dev->stats.tx_bytes += bytes;
  29         netdev_completed_queue(ch->priv->net_dev, pkts, bytes);
  30
  31 +       netif_tx_unlock(net_dev);
  32         if (netif_queue_stopped(net_dev))
  33                 netif_wake_queue(net_dev);
  34