Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 45242006 authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Make flush_to_ldisc properly handle parallel calls

parent 80f50691

drivers/char/tty_buffer.c

+13 −16
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);