i40e: use the safe hash table iterator when deleting mac filters

This patch replaces hash_for_each function with hash_for_each_safe
when calling  __i40e_del_filter. The hash_for_each_safe function is
the right one to use when iterating over a hash table to safely remove
a hash entry. Otherwise, incorrect values may be read from freed memory.

Detected by CoverityScan, CID 1402048 Read from pointer after free

Signed-off-by: Lihong Yang <lihong.yang@intel.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

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

@@ -2883,6 +2883,7 @@ int i40e_ndo_set_vf_mac(struct net_device *netdev, int vf_id, u8 *mac)
 	struct i40e_mac_filter *f;
 	struct i40e_vf *vf;
 	int ret = 0;
+	struct hlist_node *h;
 	int bkt;
 
 	/* validate the request */
@@ -2921,7 +2922,7 @@ int i40e_ndo_set_vf_mac(struct net_device *netdev, int vf_id, u8 *mac)
 	/* Delete all the filters for this VSI - we're going to kill it
 	 * anyway.
 	 */
-	hash_for_each(vsi->mac_filter_hash, bkt, f, hlist)
+	hash_for_each_safe(vsi->mac_filter_hash, bkt, h, f, hlist)
 		__i40e_del_filter(vsi, f);
 
 	spin_unlock_bh(&vsi->mac_filter_hash_lock);