ptp: drop redundant kasprintf() to create worker name

Building with -Wformat-nonliteral, gcc complains

drivers/ptp/ptp_clock.c: In function ‘ptp_clock_register’:
drivers/ptp/ptp_clock.c:239:26: warning: format not a string literal and no format arguments [-Wformat-nonliteral]
            worker_name : info->name);

kthread_create_worker takes fmt+varargs to set the name of the
worker, and that happens with a vsnprintf() to a stack buffer (that is
then copied into task_comm). So there's no reason not to just pass
"ptp%d", ptp->index to kthread_create_worker() and avoid the
intermediate worker_name variable.

Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Acked-by: Richard Cochran <richardcochran@gmail.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/ptp/ptp_clock.c

@@ -232,12 +232,8 @@ struct ptp_clock *ptp_clock_register(struct ptp_clock_info *info,
 	init_waitqueue_head(&ptp->tsev_wq);
 
 	if (ptp->info->do_aux_work) {
-		char *worker_name = kasprintf(GFP_KERNEL, "ptp%d", ptp->index);
-
 		kthread_init_delayed_work(&ptp->aux_work, ptp_aux_kworker);
-		ptp->kworker = kthread_create_worker(0, worker_name ?
-						     worker_name : info->name);
-		kfree(worker_name);
+		ptp->kworker = kthread_create_worker(0, "ptp%d", ptp->index);
 		if (IS_ERR(ptp->kworker)) {
 			err = PTR_ERR(ptp->kworker);
 			pr_err("failed to create ptp aux_worker %d\n", err);