Commit 7004b26f authored by Jijie Shao's avatar Jijie Shao Committed by Jakub Kicinski
Browse files

net: hibmcge: fix the division by zero issue 



When the network port is down, the queue is released, and ring->len is 0.
In debugfs, hbg_get_queue_used_num() will be called,
which may lead to a division by zero issue.

This patch adds a check, if ring->len is 0,
hbg_get_queue_used_num() directly returns 0.

Fixes: 40735e75 ("net: hibmcge: Implement .ndo_start_xmit function")
Signed-off-by: default avatarJijie Shao <shaojijie@huawei.com>
Reviewed-by: default avatarSimon Horman <horms@kernel.org>
Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent c875503a

drivers/net/ethernet/hisilicon/hibmcge/hbg_txrx.h

+6 −1
Original line number Diff line number Diff line
@@ -29,7 +29,12 @@ static inline bool hbg_fifo_is_full(struct hbg_priv *priv, enum hbg_dir dir) 


static inline u32 hbg_get_queue_used_num(struct hbg_ring *ring)

{

	return (ring->ntu + ring->len - ring->ntc) % ring->len;

	u32 len = READ_ONCE(ring->len);



	if (!len)

		return 0;



	return (READ_ONCE(ring->ntu) + len - READ_ONCE(ring->ntc)) % len;

}



netdev_tx_t hbg_net_start_xmit(struct sk_buff *skb, struct net_device *netdev);