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Merge branch 'tty-fixes'

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* 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
This commit is contained in:
Linus Torvalds 2009-10-14 15:34:55 -07:00
commit d6047d79b9
3 changed files with 33 additions and 17 deletions
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31
drivers/char/tty_buffer.c
View file

@ -402,28 +402,26 @@ static void flush_to_ldisc(struct work_struct *work)
container_of(work, struct tty_struct, buf.work.work); container_of(work, struct tty_struct, buf.work.work);
unsigned long flags; unsigned long flags;
struct tty_ldisc *disc; struct tty_ldisc *disc;
struct tty_buffer *tbuf, *head;
char *char_buf;
unsigned char *flag_buf;
disc = tty_ldisc_ref(tty); disc = tty_ldisc_ref(tty);
if (disc == NULL) /* !TTY_LDISC */ if (disc == NULL) /* !TTY_LDISC */
return; return;
spin_lock_irqsave(&tty->buf.lock, flags); spin_lock_irqsave(&tty->buf.lock, flags);
/* So we know a flush is running */
set_bit(TTY_FLUSHING, &tty->flags); if (!test_and_set_bit(TTY_FLUSHING, &tty->flags)) {
head = tty->buf.head; struct tty_buffer *head;
if (head != NULL) { while ((head = tty->buf.head) != NULL) {
tty->buf.head = NULL; int count;
for (;;) { char *char_buf;
int count = head->commit - head->read; unsigned char *flag_buf;
count = head->commit - head->read;
if (!count) { if (!count) {
if (head->next == NULL) if (head->next == NULL)
break; break;
tbuf = head; tty->buf.head = head->next;
head = head->next; tty_buffer_free(tty, head);
tty_buffer_free(tty, tbuf);
continue; continue;
} }
/* Ldisc or user is trying to flush the buffers /* 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); flag_buf, count);
spin_lock_irqsave(&tty->buf.lock, flags); spin_lock_irqsave(&tty->buf.lock, flags);
} }
/* Restore the queue head */ clear_bit(TTY_FLUSHING, &tty->flags);
tty->buf.head = head;
} }
/* We may have a deferred request to flush the input buffer, /* We may have a deferred request to flush the input buffer,
if so pull the chain under the lock and empty the queue */ if so pull the chain under the lock and empty the queue */
if (test_bit(TTY_FLUSHPENDING, &tty->flags)) { 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); clear_bit(TTY_FLUSHPENDING, &tty->flags);
wake_up(&tty->read_wait); wake_up(&tty->read_wait);
} }
clear_bit(TTY_FLUSHING, &tty->flags);
spin_unlock_irqrestore(&tty->buf.lock, flags); spin_unlock_irqrestore(&tty->buf.lock, flags);
tty_ldisc_deref(disc); 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) void tty_flush_to_ldisc(struct tty_struct *tty)
{ {
flush_to_ldisc(&tty->buf.work.work); flush_delayed_work(&tty->buf.work);
} }
/** /**

1
include/linux/workqueue.h
View file

@ -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_workqueue(struct workqueue_struct *wq);
extern void flush_scheduled_work(void); 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(struct work_struct *work);
extern int schedule_work_on(int cpu, struct work_struct *work); extern int schedule_work_on(int cpu, struct work_struct *work);

18
kernel/workqueue.c
View file

@ -639,6 +639,24 @@ int schedule_delayed_work(struct delayed_work *dwork,
} }
EXPORT_SYMBOL(schedule_delayed_work); 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 * schedule_delayed_work_on - queue work in global workqueue on CPU after delay
* @cpu: cpu to use * @cpu: cpu to use