[PATCH net v2 2/4] net: ll_temac: Add more error handling of dma_map_single() calls

From: Esben Haabendal
Date: Fri Feb 21 2020 - 01:47:43 EST


This adds error handling to the remaining dma_map_single() calls, so that
behavior is well defined if/when we run out of DMA memory.

Fixes: 92744989533c ("net: add Xilinx ll_temac device driver")
Signed-off-by: Esben Haabendal <esben@xxxxxxxxxx>
---
drivers/net/ethernet/xilinx/ll_temac_main.c | 26 +++++++++++++++++++--
1 file changed, 24 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/xilinx/ll_temac_main.c b/drivers/net/ethernet/xilinx/ll_temac_main.c
index 996004ef8bd4..c368c3914bda 100644
--- a/drivers/net/ethernet/xilinx/ll_temac_main.c
+++ b/drivers/net/ethernet/xilinx/ll_temac_main.c
@@ -367,6 +367,8 @@ static int temac_dma_bd_init(struct net_device *ndev)
skb_dma_addr = dma_map_single(ndev->dev.parent, skb->data,
XTE_MAX_JUMBO_FRAME_SIZE,
DMA_FROM_DEVICE);
+ if (dma_mapping_error(ndev->dev.parent, skb_dma_addr))
+ goto out;
lp->rx_bd_v[i].phys = cpu_to_be32(skb_dma_addr);
lp->rx_bd_v[i].len = cpu_to_be32(XTE_MAX_JUMBO_FRAME_SIZE);
lp->rx_bd_v[i].app0 = cpu_to_be32(STS_CTRL_APP0_IRQONEND);
@@ -863,12 +865,13 @@ temac_start_xmit(struct sk_buff *skb, struct net_device *ndev)
skb_dma_addr = dma_map_single(ndev->dev.parent, skb->data,
skb_headlen(skb), DMA_TO_DEVICE);
cur_p->len = cpu_to_be32(skb_headlen(skb));
+ if (WARN_ON_ONCE(dma_mapping_error(ndev->dev.parent, skb_dma_addr)))
+ return NETDEV_TX_BUSY;
cur_p->phys = cpu_to_be32(skb_dma_addr);
ptr_to_txbd((void *)skb, cur_p);

for (ii = 0; ii < num_frag; ii++) {
- lp->tx_bd_tail++;
- if (lp->tx_bd_tail >= TX_BD_NUM)
+ if (++lp->tx_bd_tail >= TX_BD_NUM)
lp->tx_bd_tail = 0;

cur_p = &lp->tx_bd_v[lp->tx_bd_tail];
@@ -876,6 +879,25 @@ temac_start_xmit(struct sk_buff *skb, struct net_device *ndev)
skb_frag_address(frag),
skb_frag_size(frag),
DMA_TO_DEVICE);
+ if (dma_mapping_error(ndev->dev.parent, skb_dma_addr)) {
+ if (--lp->tx_bd_tail < 0)
+ lp->tx_bd_tail = TX_BD_NUM - 1;
+ cur_p = &lp->tx_bd_v[lp->tx_bd_tail];
+ while (--ii >= 0) {
+ --frag;
+ dma_unmap_single(ndev->dev.parent,
+ be32_to_cpu(cur_p->phys),
+ skb_frag_size(frag),
+ DMA_TO_DEVICE);
+ if (--lp->tx_bd_tail < 0)
+ lp->tx_bd_tail = TX_BD_NUM - 1;
+ cur_p = &lp->tx_bd_v[lp->tx_bd_tail];
+ }
+ dma_unmap_single(ndev->dev.parent,
+ be32_to_cpu(cur_p->phys),
+ skb_headlen(skb), DMA_TO_DEVICE);
+ return NETDEV_TX_BUSY;
+ }
cur_p->phys = cpu_to_be32(skb_dma_addr);
cur_p->len = cpu_to_be32(skb_frag_size(frag));
cur_p->app0 = 0;
--
2.25.0