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um: race fix: initialize delayed_work *before* registering IRQ

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... since chan_interrupt() might schedule it if there's too much
incoming data.  Kill task argument of chan_interrupt(), while
we are at it - it's always &line->task.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Richard Weinberger <richard@nod.at>
This commit is contained in:
Al Viro 2011-09-10 08:17:04 -04:00 committed by Richard Weinberger
parent 5eaa3411a8
commit 0fcd719934
3 changed files with 15 additions and 18 deletions
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2
arch/um/drivers/chan.h
View File

@ -27,7 +27,7 @@ struct chan {
void *data;
};
extern void chan_interrupt(struct line *line, struct delayed_work *task,
extern void chan_interrupt(struct line *line,
struct tty_struct *tty, int irq);
extern int parse_chan_pair(char *str, struct line *line, int device,
const struct chan_opts *opts, char **error_out);

15
arch/um/drivers/chan_kern.c
View File

@ -146,12 +146,22 @@ void chan_enable_winch(struct chan *chan, struct tty_struct *tty)
register_winch(chan->fd, tty);
}
static void line_timer_cb(struct work_struct *work)
{
struct line *line = container_of(work, struct line, task.work);
if (!line->throttled)
chan_interrupt(line, line->tty, line->driver->read_irq);
}
int enable_chan(struct line *line)
{
struct list_head *ele;
struct chan *chan;
int err;
INIT_DELAYED_WORK(&line->task, line_timer_cb);
list_for_each(ele, &line->chan_list) {
chan = list_entry(ele, struct chan, list);
err = open_one_chan(chan);
@ -552,8 +562,7 @@ int parse_chan_pair(char *str, struct line *line, int device,
return 0;
}
void chan_interrupt(struct line *line, struct delayed_work *task,
struct tty_struct *tty, int irq)
void chan_interrupt(struct line *line, struct tty_struct *tty, int irq)
{
struct chan *chan = line->chan_in;
int err;
@ -564,7 +573,7 @@ void chan_interrupt(struct line *line, struct delayed_work *task,
do {
if (tty && !tty_buffer_request_room(tty, 1)) {
schedule_delayed_work(task, 1);
schedule_delayed_work(&line->task, 1);
goto out;
}
err = chan->ops->read(chan->fd, &c, chan->data);

16
arch/um/drivers/line.c
View File

@ -21,19 +21,10 @@ static irqreturn_t line_interrupt(int irq, void *data)
struct line *line = chan->line;
if (line)
chan_interrupt(line, &line->task, line->tty, irq);
chan_interrupt(line, line->tty, irq);
return IRQ_HANDLED;
}
static void line_timer_cb(struct work_struct *work)
{
struct line *line = container_of(work, struct line, task.work);
if (!line->throttled)
chan_interrupt(line, &line->task, line->tty,
line->driver->read_irq);
}
/*
* Returns the free space inside the ring buffer of this line.
*
@ -327,8 +318,7 @@ void line_unthrottle(struct tty_struct *tty)
struct line *line = tty->driver_data;
line->throttled = 0;
chan_interrupt(line, &line->task, tty,
line->driver->read_irq);
chan_interrupt(line, tty, line->driver->read_irq);
/*
* Maybe there is enough stuff pending that calling the interrupt
@ -424,8 +414,6 @@ int line_open(struct line *lines, struct tty_struct *tty)
if (err) /* line_close() will be called by our caller */
goto out_unlock;
INIT_DELAYED_WORK(&line->task, line_timer_cb);
if (!line->sigio) {
chan_enable_winch(line->chan_out, tty);
line->sigio = 1;