net/smc: free link group without pending free_work only

Make sure there is no pending or running free_work worker for the link
group when freeing the link group.
Signed-off-by: NUrsula Braun <ubraun@linux.vnet.ibm.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/smc/af_smc.c

@@ -1477,6 +1477,7 @@ static void __exit smc_exit(void)
 	spin_unlock_bh(&smc_lgr_list.lock);
 	list_for_each_entry_safe(lgr, lg, &lgr_freeing_list, list) {
 		list_del_init(&lgr->list);
+		cancel_delayed_work_sync(&lgr->free_work);
 		smc_lgr_free(lgr); /* free link group */
 	}
 	static_branch_disable(&tcp_have_smc);

net/smc/smc_core.c

@@ -140,7 +140,8 @@ static void smc_lgr_free_work(struct work_struct *work)
 	list_del_init(&lgr->list); /* remove from smc_lgr_list */
 free:
 	spin_unlock_bh(&smc_lgr_list.lock);
-	smc_lgr_free(lgr);
+	if (!delayed_work_pending(&lgr->free_work))
+		smc_lgr_free(lgr);
 }
 
 /* create a new SMC link group */