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Commit d6047d79 authored by Linus Torvalds's avatar Linus Torvalds
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Merge branch 'tty-fixes' 

* branch 'tty-fixes':
  tty: use the new 'flush_delayed_work()' helper to do ldisc flush
  workqueue: add 'flush_delayed_work()' to run and wait for delayed work
  Make flush_to_ldisc properly handle parallel calls
parents 601adfed 514fc01d

drivers/char/tty_buffer.c

+14 −17
Original line number Diff line number Diff line
@@ -402,28 +402,26 @@ static void flush_to_ldisc(struct work_struct *work) 
		container_of(work, struct tty_struct, buf.work.work);

	unsigned long 	flags;

	struct tty_ldisc *disc;

	struct tty_buffer *tbuf, *head;

	char *char_buf;

	unsigned char *flag_buf;



	disc = tty_ldisc_ref(tty);

	if (disc == NULL)	/*  !TTY_LDISC */

		return;



	spin_lock_irqsave(&tty->buf.lock, flags);

	/* So we know a flush is running */

	set_bit(TTY_FLUSHING, &tty->flags);

	head = tty->buf.head;

	if (head != NULL) {

		tty->buf.head = NULL;

		for (;;) {

			int count = head->commit - head->read;



	if (!test_and_set_bit(TTY_FLUSHING, &tty->flags)) {

		struct tty_buffer *head;

		while ((head = tty->buf.head) != NULL) {

			int count;

			char *char_buf;

			unsigned char *flag_buf;



			count = head->commit - head->read;

			if (!count) {

				if (head->next == NULL)

					break;

				tbuf = head;

				head = head->next;

				tty_buffer_free(tty, tbuf);

				tty->buf.head = head->next;

				tty_buffer_free(tty, head);

				continue;

			}

			/* Ldisc or user is trying to flush the buffers
@@ -445,9 +443,9 @@ static void flush_to_ldisc(struct work_struct *work) 
							flag_buf, count);

			spin_lock_irqsave(&tty->buf.lock, flags);

		}

		/* Restore the queue head */

		tty->buf.head = head;

		clear_bit(TTY_FLUSHING, &tty->flags);

	}



	/* We may have a deferred request to flush the input buffer,

	   if so pull the chain under the lock and empty the queue */

	if (test_bit(TTY_FLUSHPENDING, &tty->flags)) {
@@ -455,7 +453,6 @@ static void flush_to_ldisc(struct work_struct *work) 
		clear_bit(TTY_FLUSHPENDING, &tty->flags);

		wake_up(&tty->read_wait);

	}

	clear_bit(TTY_FLUSHING, &tty->flags);

	spin_unlock_irqrestore(&tty->buf.lock, flags);



	tty_ldisc_deref(disc);
@@ -471,7 +468,7 @@ static void flush_to_ldisc(struct work_struct *work) 
 */

void tty_flush_to_ldisc(struct tty_struct *tty)

{

	flush_to_ldisc(&tty->buf.work.work);

	flush_delayed_work(&tty->buf.work);

}



/**

include/linux/workqueue.h

+1 −0
Original line number Diff line number Diff line
@@ -207,6 +207,7 @@ extern int queue_delayed_work_on(int cpu, struct workqueue_struct *wq, 


extern void flush_workqueue(struct workqueue_struct *wq);

extern void flush_scheduled_work(void);

extern void flush_delayed_work(struct delayed_work *work);



extern int schedule_work(struct work_struct *work);

extern int schedule_work_on(int cpu, struct work_struct *work);

kernel/workqueue.c

+18 −0
Original line number Diff line number Diff line
@@ -639,6 +639,24 @@ int schedule_delayed_work(struct delayed_work *dwork, 
}

EXPORT_SYMBOL(schedule_delayed_work);



/**

 * flush_delayed_work - block until a dwork_struct's callback has terminated

 * @dwork: the delayed work which is to be flushed

 *

 * Any timeout is cancelled, and any pending work is run immediately.

 */

void flush_delayed_work(struct delayed_work *dwork)

{

	if (del_timer(&dwork->timer)) {

		struct cpu_workqueue_struct *cwq;

		cwq = wq_per_cpu(keventd_wq, get_cpu());

		__queue_work(cwq, &dwork->work);

		put_cpu();

	}

	flush_work(&dwork->work);

}

EXPORT_SYMBOL(flush_delayed_work);



/**

 * schedule_delayed_work_on - queue work in global workqueue on CPU after delay

 * @cpu: cpu to use