ice: tighter control over VSI_DOWN state

The driver had comments to the effect of: This flag should be set before
calling this function. While reviewing code it was found that there were
several violations of this policy, which could introduce hard to find
bugs or races.

Fix the violations of the "VSI DOWN state must be set before calling
ice_down" and make checking the state into code with a WARN_ON.

Signed-off-by: Jesse Brandeburg <[email protected]>
Tested-by: Gurucharan G <[email protected]>
Signed-off-by: Tony Nguyen <[email protected]>

Author: jbrandeb

drivers/net/ethernet/intel/ice/ice_ethtool.c

@@ -1280,8 +1280,10 @@ static int ice_set_priv_flags(struct net_device *netdev, u32 flags)
 	}
 	if (test_bit(ICE_FLAG_LEGACY_RX, change_flags)) {
 		/* down and up VSI so that changes of Rx cfg are reflected. */
-		ice_down(vsi);
-		ice_up(vsi);
+		if (!test_and_set_bit(ICE_VSI_DOWN, vsi->state)) {
+			ice_down(vsi);
+			ice_up(vsi);
+		}
 	}
 	/* don't allow modification of this flag when a single VF is in
 	 * promiscuous mode because it's not supported

drivers/net/ethernet/intel/ice/ice_main.c

@@ -6229,14 +6229,15 @@ static void ice_napi_disable_all(struct ice_vsi *vsi)
 /**
  * ice_down - Shutdown the connection
  * @vsi: The VSI being stopped
+ *
+ * Caller of this function is expected to set the vsi->state ICE_DOWN bit
  */
 int ice_down(struct ice_vsi *vsi)
 {
 	int i, tx_err, rx_err, link_err = 0;
 
-	/* Caller of this function is expected to set the
-	 * vsi->state ICE_DOWN bit
-	 */
+	WARN_ON(!test_bit(ICE_VSI_DOWN, vsi->state));
+
 	if (vsi->netdev && vsi->type == ICE_VSI_PF) {
 		netif_carrier_off(vsi->netdev);
 		netif_tx_disable(vsi->netdev);