From: Shannon Nelson <shannon.nelson@oracle.com>
Date: Mon, 24 Jul 2017 18:17:42 -0700
Subject: i40e: limit lan queue count in large CPU count machine
Patch-mainline: v4.15-rc1
Git-commit: e50d5751c807853cd0fce0b5c46479cc6274014f
References: bsc#1101816 FATE#325147 FATE#325149

When a machine has more CPUs than queue pairs, e.g. 512 cores, the
counting gets a little funky and turns off Flow Director with the
message:
  not enough queues for Flow Director. Flow Director feature is disabled

This patch limits the number of lan queues initially allocated to
be sure we have some left for FD and other features.

Signed-off-by: Shannon Nelson <shannon.nelson@oracle.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Acked-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
---
 drivers/net/ethernet/intel/i40e/i40e_main.c |   11 +++++++----
 1 file changed, 7 insertions(+), 4 deletions(-)

--- a/drivers/net/ethernet/intel/i40e/i40e_main.c
+++ b/drivers/net/ethernet/intel/i40e/i40e_main.c
@@ -11093,6 +11093,7 @@ static int i40e_setup_pf_switch(struct i
 static void i40e_determine_queue_usage(struct i40e_pf *pf)
 {
 	int queues_left;
+	int q_max;
 
 	pf->num_lan_qps = 0;
 
@@ -11139,10 +11140,12 @@ static void i40e_determine_queue_usage(s
 					I40E_FLAG_DCB_ENABLED);
 			dev_info(&pf->pdev->dev, "not enough queues for DCB. DCB is disabled.\n");
 		}
-		pf->num_lan_qps = max_t(int, pf->rss_size_max,
-					num_online_cpus());
-		pf->num_lan_qps = min_t(int, pf->num_lan_qps,
-					pf->hw.func_caps.num_tx_qp);
+
+		/* limit lan qps to the smaller of qps, cpus or msix */
+		q_max = max_t(int, pf->rss_size_max, num_online_cpus());
+		q_max = min_t(int, q_max, pf->hw.func_caps.num_tx_qp);
+		q_max = min_t(int, q_max, pf->hw.func_caps.num_msix_vectors);
+		pf->num_lan_qps = q_max;
 
 		queues_left -= pf->num_lan_qps;
 	}