Commit 0fcd7199 authored by Al Viro's avatar Al Viro Committed by Richard Weinberger
Browse files

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



... 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: default avatarAl Viro <viro@zeniv.linux.org.uk>
Signed-off-by: default avatarRichard Weinberger <richard@nod.at>
parent 5eaa3411

arch/um/drivers/chan.h

+1 −1
Original line number Diff line number Diff line
@@ -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);

arch/um/drivers/chan_kern.c

+12 −3
Original line number Diff line number Diff line
@@ -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);

arch/um/drivers/line.c

+2 −14
Original line number Diff line number Diff line
@@ -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;