[PATCH AUTOSEL 5.2 107/123] net: hisilicon: fix hip04-xmit never return TX_BUSY

Sasha Levin
2019-08-14T02:15:45Z

From: Jiangfeng Xiao <xiaojiangfeng@huawei.com>

[ Upstream commit f2243b82785942be519016067ee6c55a063bbfe2 ]

TX_DESC_NUM is 256, in tx_count, the maximum value of
mod(TX_DESC_NUM - 1) is 254, the variable "count" in
the hip04_mac_start_xmit function is never equal to
(TX_DESC_NUM - 1), so hip04_mac_start_xmit never
return NETDEV_TX_BUSY.

tx_count is modified to mod(TX_DESC_NUM) so that
the maximum value of tx_count can reach
(TX_DESC_NUM - 1), then hip04_mac_start_xmit can reurn
NETDEV_TX_BUSY.

Signed-off-by: Jiangfeng Xiao <xiaojiangfeng@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/net/ethernet/hisilicon/hip04_eth.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/hisilicon/hip04_eth.c b/drivers/net/ethernet/hisilicon/hip04_eth.c
index 5abe88dfe6abf..ee6da8d66cd31 100644
--- a/drivers/net/ethernet/hisilicon/hip04_eth.c
+++ b/drivers/net/ethernet/hisilicon/hip04_eth.c
@@ -181,7 +181,7 @@ struct hip04_priv {

static inline unsigned int tx_count(unsigned int head, unsigned int tail)
{
- return (head - tail) % (TX_DESC_NUM - 1);
+ return (head - tail) % TX_DESC_NUM;
}

static void hip04_config_port(struct net_device *ndev, u32 speed, u32 duplex)
--
2.20.1