The patch below does not apply to the 4.9-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 996defd7f8b5dafc1d480b7585c7c62437f80c3c Mon Sep 17 00:00:00 2001 From: Robert Hancock robert.hancock@calian.com Date: Tue, 18 Jan 2022 15:41:29 -0600 Subject: [PATCH] net: axienet: Fix TX ring slot available check

The check for whether a TX ring slot was available was incorrect, since a slot which had been loaded with transmit data but the device had not started transmitting would be treated as available, potentially causing non-transmitted slots to be overwritten. The control field in the descriptor should be checked, rather than the status field (which may only be updated when the device completes the entry).

Fixes: 8a3b7a252dca9 ("drivers/net/ethernet/xilinx: added Xilinx AXI Ethernet driver") Signed-off-by: Robert Hancock robert.hancock@calian.com Signed-off-by: David S. Miller davem@davemloft.net

diff --git a/drivers/net/ethernet/xilinx/xilinx_axienet_main.c b/drivers/net/ethernet/xilinx/xilinx_axienet_main.c index 3f92001bacaf..85fe2b3bd37a 100644 --- a/drivers/net/ethernet/xilinx/xilinx_axienet_main.c +++ b/drivers/net/ethernet/xilinx/xilinx_axienet_main.c @@ -643,7 +643,6 @@ static int axienet_free_tx_chain(struct net_device *ndev, u32 first_bd, if (cur_p->skb && (status & XAXIDMA_BD_STS_COMPLETE_MASK)) dev_consume_skb_irq(cur_p->skb);

- cur_p->cntrl = 0; cur_p->app0 = 0; cur_p->app1 = 0; cur_p->app2 = 0; @@ -651,6 +650,7 @@ static int axienet_free_tx_chain(struct net_device *ndev, u32 first_bd, cur_p->skb = NULL; /* ensure our transmit path and device don't prematurely see status cleared */ wmb(); + cur_p->cntrl = 0; cur_p->status = 0;

if (sizep) @@ -713,7 +713,7 @@ static inline int axienet_check_tx_bd_space(struct axienet_local *lp, /* Ensure we see all descriptor updates from device or TX IRQ path */ rmb(); cur_p = &lp->tx_bd_v[(lp->tx_bd_tail + num_frag) % lp->tx_bd_num]; - if (cur_p->status & XAXIDMA_BD_STS_ALL_MASK) + if (cur_p->cntrl) return NETDEV_TX_BUSY; return 0; }