i40e: Add a SW workaround for lost interrupts
This patch adds a workaround for cases where we might have
interrupts that got lost but WB happened.
If that happens without this patch we will see a tx_timeout.
To work around it, this patch goes ahead and reschedules NAPI
in that situation, if NAPI is not already scheduled.
We also add a counter in ethtool to keep track of when
we detect a case of tx_lost_interrupt.
Note: napi_reschedule() can be safely called from process/service_task
context and is done in other drivers as well without an issue.
Change-ID: I00f98f1ce3774524d9421227652bef20fcbd0d20
Signed-off-by: Anjali Singhai Jain <anjali.singhai@intel.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
diff --git a/drivers/net/ethernet/intel/i40evf/i40e_txrx.c b/drivers/net/ethernet/intel/i40evf/i40e_txrx.c
index 76bad75..0f73a4f 100644
--- a/drivers/net/ethernet/intel/i40evf/i40e_txrx.c
+++ b/drivers/net/ethernet/intel/i40evf/i40e_txrx.c
@@ -129,15 +129,19 @@
/**
* i40evf_get_tx_pending - how many Tx descriptors not processed
* @tx_ring: the ring of descriptors
+ * @in_sw: is tx_pending being checked in SW or HW
*
* Since there is no access to the ring head register
* in XL710, we need to use our local copies
**/
-u32 i40evf_get_tx_pending(struct i40e_ring *ring)
+u32 i40evf_get_tx_pending(struct i40e_ring *ring, bool in_sw)
{
u32 head, tail;
- head = i40e_get_head(ring);
+ if (!in_sw)
+ head = i40e_get_head(ring);
+ else
+ head = ring->next_to_clean;
tail = readl(ring->tail);
if (head != tail)
@@ -259,7 +263,7 @@
* them to be written back in case we stay in NAPI.
* In this mode on X722 we do not enable Interrupt.
*/
- j = i40evf_get_tx_pending(tx_ring);
+ j = i40evf_get_tx_pending(tx_ring, false);
if (budget &&
((j / (WB_STRIDE + 1)) == 0) && (j > 0) &&