timers: Get rid of del_singleshot_timer_sync()

del_singleshot_timer_sync() used to be an optimization for deleting timers
which are not rearmed from the timer callback function.

This optimization turned out to be broken and got mapped to
del_timer_sync() about 17 years ago.

Get rid of the undocumented indirection and use del_timer_sync() directly.

No functional change.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Guenter Roeck <linux@roeck-us.net>
Reviewed-by: Jacob Keller <jacob.e.keller@intel.com>
Reviewed-by: Anna-Maria Behnsen <anna-maria@linutronix.de>
Link: https://lore.kernel.org/r/20221123201624.706987932@linutronix.de

drivers/char/tpm/tpm-dev-common.c

@@ -155,7 +155,7 @@ ssize_t tpm_common_read(struct file *file, char __user *buf,
 out:
 	if (!priv->response_length) {
 		*off = 0;
-		del_singleshot_timer_sync(&priv->user_read_timer);
+		del_timer_sync(&priv->user_read_timer);
 		flush_work(&priv->timeout_work);
 	}
 	mutex_unlock(&priv->buffer_mutex);
@@ -262,7 +262,7 @@ __poll_t tpm_common_poll(struct file *file, poll_table *wait)
 void tpm_common_release(struct file *file, struct file_priv *priv)
 {
 	flush_work(&priv->async_work);
-	del_singleshot_timer_sync(&priv->user_read_timer);
+	del_timer_sync(&priv->user_read_timer);
 	flush_work(&priv->timeout_work);
 	file->private_data = NULL;
 	priv->response_length = 0;

drivers/staging/wlan-ng/hfa384x_usb.c

@@ -1116,8 +1116,8 @@ cleanup:
 		if (ctlx == get_active_ctlx(hw)) {
 			spin_unlock_irqrestore(&hw->ctlxq.lock, flags);
 
-			del_singleshot_timer_sync(&hw->reqtimer);
-			del_singleshot_timer_sync(&hw->resptimer);
+			del_timer_sync(&hw->reqtimer);
+			del_timer_sync(&hw->resptimer);
 			hw->req_timer_done = 1;
 			hw->resp_timer_done = 1;
 			usb_kill_urb(&hw->ctlx_urb);

drivers/staging/wlan-ng/prism2usb.c

@@ -170,9 +170,9 @@ static void prism2sta_disconnect_usb(struct usb_interface *interface)
 		 */
 		prism2sta_ifstate(wlandev, P80211ENUM_ifstate_disable);
 
-		del_singleshot_timer_sync(&hw->throttle);
-		del_singleshot_timer_sync(&hw->reqtimer);
-		del_singleshot_timer_sync(&hw->resptimer);
+		del_timer_sync(&hw->throttle);
+		del_timer_sync(&hw->reqtimer);
+		del_timer_sync(&hw->resptimer);
 
 		/* Unlink all the URBs. This "removes the wheels"
 		 * from the entire CTLX handling mechanism.

include/linux/timer.h

@@ -190,8 +190,6 @@ extern int try_to_del_timer_sync(struct timer_list *timer);
 # define del_timer_sync(t)		del_timer(t)
 #endif
 
-#define del_singleshot_timer_sync(t) del_timer_sync(t)
-
 extern void init_timers(void);
 struct hrtimer;
 extern enum hrtimer_restart it_real_fn(struct hrtimer *);

kernel/time/timer.c

@@ -1933,7 +1933,7 @@ signed long __sched schedule_timeout(signed long timeout)
 	timer_setup_on_stack(&timer.timer, process_timeout, 0);
 	__mod_timer(&timer.timer, expire, MOD_TIMER_NOTPENDING);
 	schedule();
-	del_singleshot_timer_sync(&timer.timer);
+	del_timer_sync(&timer.timer);
 
 	/* Remove the timer from the object tracker */
 	destroy_timer_on_stack(&timer.timer);

net/sunrpc/xprt.c

@@ -1164,7 +1164,7 @@ xprt_request_enqueue_receive(struct rpc_task *task)
 	spin_unlock(&xprt->queue_lock);
 
 	/* Turn off autodisconnect */
-	del_singleshot_timer_sync(&xprt->timer);
+	del_timer_sync(&xprt->timer);
 	return 0;
 }