net: axienet: Fix TX ring slot available check
authorRobert Hancock <robert.hancock@calian.com>
Tue, 18 Jan 2022 21:41:29 +0000 (15:41 -0600)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Thu, 27 Jan 2022 10:05:33 +0000 (11:05 +0100)
commit 996defd7f8b5dafc1d480b7585c7c62437f80c3c upstream.

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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
drivers/net/ethernet/xilinx/xilinx_axienet_main.c

index cc3c9eb9c4ccb0a274085103f8cc97d116624d81..5fc9ced4ec566ce216a862708cb8caa92efd59a1 100644 (file)
@@ -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;
 }