From: Dennis Dalessandro <dennis.dalessandro@intel.com>
Date: Mon, 6 Nov 2017 06:39:29 -0800
Subject: IB/hfi1: Handle initial value of 0 for CCTI setting
Patch-mainline: v4.15-rc1
Git-commit: 685894dd9bd03b92803fbc72565789713f067d4c
References: bsc#1096793 FATE#325050

When the driver is loaded it sets the default CCTI value to be 0. When the FM
starts and CCA is disabled the driver sets the max value to 65535 due the driver
subtracting 1 from 0 and the fact that the CCTI value is a u16.

Special case the subtraction to find the index for a 0 value.

Reviewed-by: Mike Marciniszyn <mike.marciniszyn@intel.com>
Signed-off-by: Dennis Dalessandro <dennis.dalessandro@intel.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>
Acked-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
---
 drivers/infiniband/hw/hfi1/mad.c |    6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

--- a/drivers/infiniband/hw/hfi1/mad.c
+++ b/drivers/infiniband/hw/hfi1/mad.c
@@ -3702,7 +3702,11 @@ static void apply_cc_state(struct hfi1_p
 
 	*new_cc_state = *old_cc_state;
 
-	new_cc_state->cct.ccti_limit = ppd->total_cct_entry - 1;
+	if (ppd->total_cct_entry)
+		new_cc_state->cct.ccti_limit = ppd->total_cct_entry - 1;
+	else
+		new_cc_state->cct.ccti_limit = 0;
+
 	memcpy(new_cc_state->cct.entries, ppd->ccti_entries,
 	       ppd->total_cct_entry * sizeof(struct ib_cc_table_entry));