i40e: acquire VSI pointer only after VF is initialized

This change simplifies the VF initialization check and also minimizes
the delay between acquiring the VSI pointer and using it. As known by
the commit being fixed, there is a risk of the VSI pointer getting
changed. Therefore minimize the delay between getting and using the
pointer.

Fixes: 9889707b ("i40e: Fix crash caused by stress setting of VF MAC addresses")
Signed-off-by: NStefan Assmann <sassmann@kpanic.de>
Reviewed-by: NJacob Keller <jacob.e.keller@intel.com>
Tested-by: NKonrad Jankowski <konrad0.jankowski@intel.com>
Signed-off-by: NTony Nguyen <anthony.l.nguyen@intel.com>

drivers/net/ethernet/intel/i40e/i40e_virtchnl_pf.c

@@ -4046,20 +4046,16 @@ int i40e_ndo_set_vf_mac(struct net_device *netdev, int vf_id, u8 *mac)
 		goto error_param;
 
 	vf = &pf->vf[vf_id];
-	vsi = pf->vsi[vf->lan_vsi_idx];
 
 	/* When the VF is resetting wait until it is done.
 	 * It can take up to 200 milliseconds,
 	 * but wait for up to 300 milliseconds to be safe.
-	 * If the VF is indeed in reset, the vsi pointer has
-	 * to show on the newly loaded vsi under pf->vsi[id].
+	 * Acquire the VSI pointer only after the VF has been
+	 * properly initialized.
 	 */
 	for (i = 0; i < 15; i++) {
-		if (test_bit(I40E_VF_STATE_INIT, &vf->vf_states)) {
-			if (i > 0)
-				vsi = pf->vsi[vf->lan_vsi_idx];
+		if (test_bit(I40E_VF_STATE_INIT, &vf->vf_states))
 			break;
-		}
 		msleep(20);
 	}
 	if (!test_bit(I40E_VF_STATE_INIT, &vf->vf_states)) {
@@ -4068,6 +4064,7 @@ int i40e_ndo_set_vf_mac(struct net_device *netdev, int vf_id, u8 *mac)
 		ret = -EAGAIN;
 		goto error_param;
 	}
+	vsi = pf->vsi[vf->lan_vsi_idx];
 
 	if (is_multicast_ether_addr(mac)) {
 		dev_err(&pf->pdev->dev,