net/smc: put sk reference if close work was canceled

Note that we always hold a reference to sock when attempting
to submit close_work. Therefore, if we have successfully
canceled close_work from pending, we MUST release that reference
to avoid potential leaks.

Fixes: 42bfba9eaa33 ("net/smc: immediate termination for SMCD link groups")
Signed-off-by: D. Wythe <[e-mail]>
Reviewed-by: Dust Li <[e-mail]>
Signed-off-by: David S. Miller <[e-mail]>

net/smc/smc_close.c

···
 	struct sock *sk = &smc->sk;
 
 	release_sock(sk);
-	cancel_work_sync(&smc->conn.close_work);
+	if (cancel_work_sync(&smc->conn.close_work))
+		sock_put(sk);
 	cancel_delayed_work_sync(&smc->conn.tx_work);
 	lock_sock(sk);
 }