From: Alexander Duyck <aduyck@mirantis.com>
Date: Tue, 22 Sep 2015 21:35:41 +0000 (-0700)
Subject: ixgbe: Fix handling of NAPI budget when multiple queues are enabled per vector
X-Git-Tag: firefly_0821_release~176^2~4^2~31^2~179
X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=5c5989e0dde275bae778d6b4706cf606aca749cc;p=firefly-linux-kernel-4.4.55.git

ixgbe: Fix handling of NAPI budget when multiple queues are enabled per vector

[ 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@mirantis.com>
Tested-by: Darin Miller <darin.j.miller@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c b/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
index aed8d029b23d..cd9b284bc83b 100644
--- 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, int budget)
 	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