From 15060c042fa25d2d3c3a9bb0fc6d2d13e8a036f8 Mon Sep 17 00:00:00 2001 From: Ronald Wahl Date: Tue, 9 Jul 2024 21:58:45 +0200 Subject: [PATCH] net: ks8851: Fix potential TX stall after interface reopen commit 7a99afef17af66c276c1d6e6f4dbcac223eaf6ac upstream. The amount of TX space in the hardware buffer is tracked in the tx_space variable. The initial value is currently only set during driver probing. After closing the interface and reopening it the tx_space variable has the last value it had before close. If it is smaller than the size of the first send packet after reopeing the interface the queue will be stopped. The queue is woken up after receiving a TX interrupt but this will never happen since we did not send anything. This commit moves the initialization of the tx_space variable to the ks8851_net_open function right before starting the TX queue. Also query the value from the hardware instead of using a hard coded value. Only the SPI chip variant is affected by this issue because only this driver variant actually depends on the tx_space variable in the xmit function. Fixes: 3dc5d4454545 ("net: ks8851: Fix TX stall caused by TX buffer overrun") Cc: "David S. Miller" Cc: Eric Dumazet Cc: Jakub Kicinski Cc: Paolo Abeni Cc: Simon Horman Cc: netdev@vger.kernel.org Cc: stable@vger.kernel.org # 5.10+ Signed-off-by: Ronald Wahl Reviewed-by: Jacob Keller Link: https://patch.msgid.link/20240709195845.9089-1-rwahl@gmx.de Signed-off-by: Paolo Abeni Signed-off-by: Greg Kroah-Hartman --- drivers/net/ethernet/micrel/ks8851_common.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/net/ethernet/micrel/ks8851_common.c b/drivers/net/ethernet/micrel/ks8851_common.c index 3b59bf15b..5e58e5238 100755 --- a/drivers/net/ethernet/micrel/ks8851_common.c +++ b/drivers/net/ethernet/micrel/ks8851_common.c @@ -500,6 +500,7 @@ static int ks8851_net_open(struct net_device *dev) ks8851_wrreg16(ks, KS_IER, ks->rc_ier); ks->queued_len = 0; + ks->tx_space = ks8851_rdreg16(ks, KS_TXMIR); netif_start_queue(ks->netdev); netif_dbg(ks, ifup, ks->netdev, "network device up\n"); @@ -1056,7 +1057,6 @@ int ks8851_probe_common(struct net_device *netdev, struct device *dev, int ret; ks->netdev = netdev; - ks->tx_space = 6144; gpio = of_get_named_gpio_flags(dev->of_node, "reset-gpios", 0, NULL); if (gpio == -EPROBE_DEFER)