TTY: um/line, use tty from tty_port

This means switching to the tty refcounted model so that we will not
race with interrupts.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Cc: Jeff Dike <jdike@addtoit.com>
Cc: Richard Weinberger <richard@nod.at>
Cc: user-mode-linux-devel@lists.sourceforge.net
Signed-off-by: Richard Weinberger <richard@nod.at>

diff --git a/arch/um/drivers/chan_kern.c b/arch/um/drivers/chan_kern.c
index 45e248c..87eebfe 100644 (file)
--- a/arch/um/drivers/chan_kern.c
+++ b/arch/um/drivers/chan_kern.c
@@ -150,9 +150,11 @@ void chan_enable_winch(struct chan *chan, struct tty_struct *tty)
 static void line_timer_cb(struct work_struct *work)
 {
        struct line *line = container_of(work, struct line, task.work);
+       struct tty_struct *tty = tty_port_tty_get(&line->port);
 
        if (!line->throttled)
-               chan_interrupt(line, line->tty, line->driver->read_irq);
+               chan_interrupt(line, tty, line->driver->read_irq);
+       tty_kref_put(tty);
 }
 
 int enable_chan(struct line *line)

diff --git a/arch/um/drivers/line.c b/arch/um/drivers/line.c
index 482a7bd..fb6e4ea 100644 (file)
--- a/arch/um/drivers/line.c
+++ b/arch/um/drivers/line.c
@@ -19,9 +19,11 @@ static irqreturn_t line_interrupt(int irq, void *data)
 {
        struct chan *chan = data;
        struct line *line = chan->line;
+       struct tty_struct *tty = tty_port_tty_get(&line->port);
 
        if (line)
-               chan_interrupt(line, line->tty, irq);
+               chan_interrupt(line, tty, irq);
+       tty_kref_put(tty);
        return IRQ_HANDLED;
 }
 
@@ -333,7 +335,7 @@ static irqreturn_t line_write_interrupt(int irq, void *data)
 {
        struct chan *chan = data;
        struct line *line = chan->line;
-       struct tty_struct *tty = line->tty;
+       struct tty_struct *tty;
        int err;
 
        /*
@@ -352,10 +354,13 @@ static irqreturn_t line_write_interrupt(int irq, void *data)
        }
        spin_unlock(&line->lock);
 
+       tty = tty_port_tty_get(&line->port);
        if (tty == NULL)
                return IRQ_NONE;
 
        tty_wakeup(tty);
+       tty_kref_put(tty);
+
        return IRQ_HANDLED;
 }
 
@@ -409,7 +414,7 @@ int line_open(struct line *lines, struct tty_struct *tty)
 
        BUG_ON(tty->driver_data);
        tty->driver_data = line;
-       line->tty = tty;
+       tty_port_tty_set(&line->port, tty);
 
        err = enable_chan(line);
        if (err) /* line_close() will be called by our caller */
@@ -449,7 +454,7 @@ void line_close(struct tty_struct *tty, struct file * filp)
        if (--line->port.count)
                goto out_unlock;
 
-       line->tty = NULL;
+       tty_port_tty_set(&line->port, NULL);
        tty->driver_data = NULL;
 
        if (line->sigio) {
@@ -610,9 +615,15 @@ int line_get_config(char *name, struct line *lines, unsigned int num, char *str,
        mutex_lock(&line->count_lock);
        if (!line->valid)
                CONFIG_CHUNK(str, size, n, "none", 1);
-       else if (line->tty == NULL)
-               CONFIG_CHUNK(str, size, n, line->init_str, 1);
-       else n = chan_config_string(line, str, size, error_out);
+       else {
+               struct tty_struct *tty = tty_port_tty_get(&line->port);
+               if (tty == NULL) {
+                       CONFIG_CHUNK(str, size, n, line->init_str, 1);
+               } else {
+                       n = chan_config_string(line, str, size, error_out);
+                       tty_kref_put(tty);
+               }
+       }
        mutex_unlock(&line->count_lock);
 
        return n;

diff --git a/arch/um/drivers/line.h b/arch/um/drivers/line.h
index 0e06a1f..5b3d4fb 100644 (file)
--- a/arch/um/drivers/line.h
+++ b/arch/um/drivers/line.h
@@ -33,7 +33,6 @@ struct line_driver {
 
 struct line {
        struct tty_port port;
-       struct tty_struct *tty;
        struct mutex count_lock;
        int valid;