[PATCH 4.4 014/192] [PATCH 014/135] ixgbe: Fix handling of NAPI budget when multiple queues are enabled per vector

From: Greg Kroah-Hartman
Date: Mon Sep 12 2016 - 13:05:36 EST

4.4-stable review patch. If anyone has any objections, please let me know.


[ Upstream commit 5d6002b7b822c7423e75d4651e6790bfb5642b1b ]

This patch corrects an issue in which the polling routine would increase
the budget for Rx to at least 1 per queue if multiple queues were present.
This would result in Rx packets being processed when the budget was 0 which
is meant to indicate that no Rx can be handled.

Signed-off-by: Alexander Duyck <aduyck@xxxxxxxxxxxx>
Tested-by: Darin Miller <darin.j.miller@xxxxxxxxx>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@xxxxxxxxx>
Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
drivers/net/ethernet/intel/ixgbe/ixgbe_main.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

--- a/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
+++ b/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
@@ -2786,7 +2786,8 @@ int ixgbe_poll(struct napi_struct *napi,
ixgbe_for_each_ring(ring, q_vector->tx)
clean_complete &= !!ixgbe_clean_tx_irq(q_vector, ring);

- if (!ixgbe_qv_lock_napi(q_vector))
+ /* Exit if we are called by netpoll or busy polling is active */
+ if ((budget <= 0) || !ixgbe_qv_lock_napi(q_vector))
return budget;

/* attempt to distribute budget to each queue fairly, but don't allow