From 0fcd719934cd3521ae4a977f454e75e2be60b7ff Mon Sep 17 00:00:00 2001 From: Al Viro Date: Sat, 10 Sep 2011 08:17:04 -0400 Subject: [PATCH] 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: Al Viro Signed-off-by: Richard Weinberger --- arch/um/drivers/chan.h | 2 +- arch/um/drivers/chan_kern.c | 15 ++++++++++++--- arch/um/drivers/line.c | 16 ++-------------- 3 files changed, 15 insertions(+), 18 deletions(-) diff --git a/arch/um/drivers/chan.h b/arch/um/drivers/chan.h index 5078ec7..d3974a9 100644 --- a/arch/um/drivers/chan.h +++ b/arch/um/drivers/chan.h @@ -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); diff --git a/arch/um/drivers/chan_kern.c b/arch/um/drivers/chan_kern.c index 73d7bc0..4744b58 100644 --- a/arch/um/drivers/chan_kern.c +++ b/arch/um/drivers/chan_kern.c @@ -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); diff --git a/arch/um/drivers/line.c b/arch/um/drivers/line.c index 08f6393..9299b8a 100644 --- a/arch/um/drivers/line.c +++ b/arch/um/drivers/line.c @@ -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; -- 2.7.4