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Commit dd5eede2 authored by Jacob Keller's avatar Jacob Keller Committed by Jeff Kirsher
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fm10k: avoid divide by zero in rare cases when device is resetting 



It is possible that under rare circumstances the device is undergoing
a reset, such as when a PFLR occurs, and the device may be transmitting
simultaneously. In this case, we might attempt to divide by zero when
finding the proper r_idx. Instead, lets read the num_tx_queues once,
and make sure it's non-zero.

Signed-off-by: default avatarJacob Keller <jacob.e.keller@intel.com>
Tested-by: default avatarKrishneil Singh <krishneil.k.singh@intel.com>
Signed-off-by: default avatarJeff Kirsher <jeffrey.t.kirsher@intel.com>
parent d876c158

drivers/net/ethernet/intel/fm10k/fm10k_netdev.c

+6 −2
Original line number Diff line number Diff line
@@ -643,9 +643,13 @@ int fm10k_close(struct net_device *netdev) 
static netdev_tx_t fm10k_xmit_frame(struct sk_buff *skb, struct net_device *dev)

{

	struct fm10k_intfc *interface = netdev_priv(dev);

	int num_tx_queues = READ_ONCE(interface->num_tx_queues);

	unsigned int r_idx = skb->queue_mapping;

	int err;



	if (!num_tx_queues)

		return NETDEV_TX_BUSY;



	if ((skb->protocol == htons(ETH_P_8021Q)) &&

	    !skb_vlan_tag_present(skb)) {

		/* FM10K only supports hardware tagging, any tags in frame
@@ -698,8 +702,8 @@ static netdev_tx_t fm10k_xmit_frame(struct sk_buff *skb, struct net_device *dev) 
		__skb_put(skb, pad_len);

	}



	if (r_idx >= interface->num_tx_queues)

		r_idx %= interface->num_tx_queues;

	if (r_idx >= num_tx_queues)

		r_idx %= num_tx_queues;



	err = fm10k_xmit_frame_ring(skb, interface->tx_ring[r_idx]);