From: Parvi Kaustubhi <pkaustub@cisco.com>
Date: Wed, 1 Nov 2017 08:44:46 -0700
Subject: enic: reset fetch index
Patch-mainline: v4.15-rc1
Git-commit: e6cdfcc581866625980a89391be4e6a8b379d0c5
References: bsc#1037697

Since we are allowing rx ring size modification, reset fetch index
everytime. Otherwise it could have a stale value that can lead to a null
pointer dereference.

Signed-off-by: Govindarajulu Varadarajan <gvaradar@cisco.com>
Signed-off-by: Parvi Kaustubhi <pkaustub@cisco.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Acked-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
---
 drivers/net/ethernet/cisco/enic/vnic_rq.c |   16 ++--------------
 1 file changed, 2 insertions(+), 14 deletions(-)

--- a/drivers/net/ethernet/cisco/enic/vnic_rq.c
+++ b/drivers/net/ethernet/cisco/enic/vnic_rq.c
@@ -139,20 +139,8 @@ void vnic_rq_init(struct vnic_rq *rq, un
 	unsigned int error_interrupt_enable,
 	unsigned int error_interrupt_offset)
 {
-	u32 fetch_index = 0;
-
-	/* Use current fetch_index as the ring starting point */
-	fetch_index = ioread32(&rq->ctrl->fetch_index);
-
-	if (fetch_index == 0xFFFFFFFF) { /* check for hardware gone  */
-		/* Hardware surprise removal: reset fetch_index */
-		fetch_index = 0;
-	}
-
-	vnic_rq_init_start(rq, cq_index,
-		fetch_index, fetch_index,
-		error_interrupt_enable,
-		error_interrupt_offset);
+	vnic_rq_init_start(rq, cq_index, 0, 0, error_interrupt_enable,
+			   error_interrupt_offset);
 }
 
 unsigned int vnic_rq_error_status(struct vnic_rq *rq)