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authorLinus Torvalds <torvalds@linux-foundation.org>2009-10-14 15:34:55 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2009-10-14 15:34:55 -0700
commitd6047d79b90f6122fcbf2c3e783b507f7dd78fc6 (patch)
tree4091ff408dd6873609e3f3341b0b3972155b7201
parent601adfedba37326410760d8d60f5da99a0adfd2f (diff)
parent514fc01d389cf5d364ee3b5fec4ac1487448803e (diff)
downloadlinux-sh-d6047d79b90f6122fcbf2c3e783b507f7dd78fc6.tar.gz
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
-rw-r--r--drivers/char/tty_buffer.c31
-rw-r--r--include/linux/workqueue.h1
-rw-r--r--kernel/workqueue.c18
3 files changed, 33 insertions, 17 deletions
diff --git a/drivers/char/tty_buffer.c b/drivers/char/tty_buffer.c
index 3108991c5c8b..66fa4e10d76b 100644
--- a/drivers/char/tty_buffer.c
+++ b/drivers/char/tty_buffer.c
@@ -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);
}
/**
diff --git a/include/linux/workqueue.h b/include/linux/workqueue.h
index 7ef0c7b94f31..cf24c20de9e4 100644
--- a/include/linux/workqueue.h
+++ b/include/linux/workqueue.h
@@ -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);
diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index addfe2df93b1..ccefe574dcf7 100644
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -640,6 +640,24 @@ 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
* @dwork: job to be done