[PATCH 04/14] net: axienet: Improve DMA error handling

From: Andre Przywara
Date: Fri Jan 10 2020 - 06:55:32 EST


Since 0 is a valid DMA address, we cannot use the physical address to
check whether a TX descriptor is valid and is holding a DMA mapping.

Use the "cntrl" member of the descriptor to make this decision, as it
contains at least the length of the buffer, so 0 points to an
uninitialised buffer.

Signed-off-by: Andre Przywara <andre.przywara@xxxxxxx>
---
drivers/net/ethernet/xilinx/xilinx_axienet_main.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/xilinx/xilinx_axienet_main.c b/drivers/net/ethernet/xilinx/xilinx_axienet_main.c
index 7e90044cf2d9..ec5d01adc1d5 100644
--- a/drivers/net/ethernet/xilinx/xilinx_axienet_main.c
+++ b/drivers/net/ethernet/xilinx/xilinx_axienet_main.c
@@ -570,7 +570,7 @@ static void axienet_start_xmit_done(struct net_device *ndev)
DMA_TO_DEVICE);
if (cur_p->skb)
dev_consume_skb_irq(cur_p->skb);
- /*cur_p->phys = 0;*/
+ cur_p->cntrl = 0;
cur_p->app0 = 0;
cur_p->app1 = 0;
cur_p->app2 = 0;
@@ -1557,7 +1557,7 @@ static void axienet_dma_err_handler(unsigned long data)

for (i = 0; i < lp->tx_bd_num; i++) {
cur_p = &lp->tx_bd_v[i];
- if (cur_p->phys)
+ if (cur_p->cntrl)
dma_unmap_single(ndev->dev.parent, cur_p->phys,
(cur_p->cntrl &
XAXIDMA_BD_CTRL_LENGTH_MASK),
--
2.17.1