From: Ciara Loftus <ciara.loftus@intel.com>
Date: Tue, 9 Jun 2020 13:19:45 +0000
Subject: ice: protect ring accesses with WRITE_ONCE
Patch-mainline: v5.8-rc3
Git-commit: b1d95cc2391ffac0c5b27256a4fb0d2cfb021a29
References: jsc#SLE-12878

The READ_ONCE macro is used when reading rings prior to accessing the
statistics pointer. The corresponding WRITE_ONCE usage when allocating and
freeing the rings to ensure protected access was not in place. Introduce
this.

Signed-off-by: Ciara Loftus <ciara.loftus@intel.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/ice/ice_lib.c  |    8 ++++----
 drivers/net/ethernet/intel/ice/ice_main.c |    2 +-
 2 files changed, 5 insertions(+), 5 deletions(-)

--- a/drivers/net/ethernet/intel/ice/ice_lib.c
+++ b/drivers/net/ethernet/intel/ice/ice_lib.c
@@ -1194,7 +1194,7 @@ static void ice_vsi_clear_rings(struct i
 		for (i = 0; i < vsi->alloc_txq; i++) {
 			if (vsi->tx_rings[i]) {
 				kfree_rcu(vsi->tx_rings[i], rcu);
-				vsi->tx_rings[i] = NULL;
+				WRITE_ONCE(vsi->tx_rings[i], NULL);
 			}
 		}
 	}
@@ -1202,7 +1202,7 @@ static void ice_vsi_clear_rings(struct i
 		for (i = 0; i < vsi->alloc_rxq; i++) {
 			if (vsi->rx_rings[i]) {
 				kfree_rcu(vsi->rx_rings[i], rcu);
-				vsi->rx_rings[i] = NULL;
+				WRITE_ONCE(vsi->rx_rings[i], NULL);
 			}
 		}
 	}
@@ -1235,7 +1235,7 @@ static int ice_vsi_alloc_rings(struct ic
 		ring->vsi = vsi;
 		ring->dev = dev;
 		ring->count = vsi->num_tx_desc;
-		vsi->tx_rings[i] = ring;
+		WRITE_ONCE(vsi->tx_rings[i], ring);
 	}
 
 	/* Allocate Rx rings */
@@ -1254,7 +1254,7 @@ static int ice_vsi_alloc_rings(struct ic
 		ring->netdev = vsi->netdev;
 		ring->dev = dev;
 		ring->count = vsi->num_rx_desc;
-		vsi->rx_rings[i] = ring;
+		WRITE_ONCE(vsi->rx_rings[i], ring);
 	}
 
 	return 0;
--- a/drivers/net/ethernet/intel/ice/ice_main.c
+++ b/drivers/net/ethernet/intel/ice/ice_main.c
@@ -1702,7 +1702,7 @@ static int ice_xdp_alloc_setup_rings(str
 		xdp_ring->netdev = NULL;
 		xdp_ring->dev = dev;
 		xdp_ring->count = vsi->num_tx_desc;
-		vsi->xdp_rings[i] = xdp_ring;
+		WRITE_ONCE(vsi->xdp_rings[i], xdp_ring);
 		if (ice_setup_tx_ring(xdp_ring))
 			goto free_xdp_rings;
 		ice_set_ring_xdp(xdp_ring);