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net: nps_enet: bug fix - handle lost tx interrupts

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The tx interrupt is of edge type, and in case such interrupt is triggered
while it is masked it will not be handled even after tx interrupts are
re-enabled in the end of NAPI poll.
This will cause tx network to stop in the following scenario:
 * Rx is being handled, hence interrupts are masked.
 * Tx interrupt is triggered after checking if there is some tx to handle
   and before re-enabling the interrupts.
In this situation only rx transaction will release tx requests.

In order to handle the tx that was missed( if there was one ),
a NAPI reschdule was added after enabling the interrupts.

Signed-off-by: Elad Kanfi <eladkan@mellanox.com>
Acked-by: Noam Camus <noamca@mellanox.com>
Acked-by: Gilad Ben-Yossef <giladby@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Elad Kanfi 2016-05-09 20:13:20 +03:00 committed by David S. Miller
parent e5df49d564
commit 05c00d82f4
1 changed files with 15 additions and 0 deletions
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15
drivers/net/ethernet/ezchip/nps_enet.c
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@ -183,6 +183,9 @@ static int nps_enet_poll(struct napi_struct *napi, int budget)
work_done = nps_enet_rx_handler(ndev);
if (work_done < budget) {
u32 buf_int_enable_value = 0;
u32 tx_ctrl_value = nps_enet_reg_get(priv, NPS_ENET_REG_TX_CTL);
u32 tx_ctrl_ct =
(tx_ctrl_value & TX_CTL_CT_MASK) >> TX_CTL_CT_SHIFT;
napi_complete(napi);
@ -192,6 +195,18 @@ static int nps_enet_poll(struct napi_struct *napi, int budget)
nps_enet_reg_set(priv, NPS_ENET_REG_BUF_INT_ENABLE,
buf_int_enable_value);
/* in case we will get a tx interrupt while interrupts
* are masked, we will lose it since the tx is edge interrupt.
* specifically, while executing the code section above,
* between nps_enet_tx_handler and the interrupts enable, all
* tx requests will be stuck until we will get an rx interrupt.
* the two code lines below will solve this situation by
* re-adding ourselves to the poll list.
*/
if (priv->tx_skb && !tx_ctrl_ct)
napi_reschedule(napi);
}
return work_done;