iavf: Fix double free in iavf_reset_task

Fix double free possibility in iavf_disable_vf, as crit_lock is
freed in caller, iavf_reset_task. Add kernel-doc for iavf_disable_vf.
Remove mutex_unlock in iavf_disable_vf.
Without this patch there is double free scenario, when calling
iavf_reset_task.

Fixes: e85ff9c6 ("iavf: Fix deadlock in iavf_reset_task")
Signed-off-by: Przemyslaw Patynowski <przemyslawx.patynowski@intel.com>
Suggested-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Mateusz Palczewski <mateusz.palczewski@intel.com>
Tested-by: Konrad Jankowski <konrad0.jankowski@intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>

drivers/net/ethernet/intel/iavf/iavf_main.c

@@ -2541,6 +2541,13 @@ static void iavf_watchdog_task(struct work_struct *work)
 		queue_delayed_work(iavf_wq, &adapter->watchdog_task, HZ * 2);
 }
 
+/**
+ * iavf_disable_vf - disable VF
+ * @adapter: board private structure
+ *
+ * Set communication failed flag and free all resources.
+ * NOTE: This function is expected to be called with crit_lock being held.
+ **/
 static void iavf_disable_vf(struct iavf_adapter *adapter)
 {
 	struct iavf_mac_filter *f, *ftmp;
@@ -2595,7 +2602,6 @@ static void iavf_disable_vf(struct iavf_adapter *adapter)
 	memset(adapter->vf_res, 0, IAVF_VIRTCHNL_VF_RESOURCE_SIZE);
 	iavf_shutdown_adminq(&adapter->hw);
 	adapter->netdev->flags &= ~IFF_UP;
-	mutex_unlock(&adapter->crit_lock);
 	adapter->flags &= ~IAVF_FLAG_RESET_PENDING;
 	iavf_change_state(adapter, __IAVF_DOWN);
 	wake_up(&adapter->down_waitqueue);