diff options
| author | Jiri Slaby <jslaby@suse.cz> | 2011-08-25 15:12:04 +0200 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@suse.de> | 2011-08-25 09:00:39 -0700 |
| commit | 426929f8d3514d7f727b8c464d1eeeaf74b21519 (patch) | |
| tree | 05f84b3f6e0182dfee2f0cb720f2acc36a4134ba /drivers/tty/serial/serial_core.c | |
| parent | dfc97fcebd6a9a85335adcfc0e4d0a204bbaea35 (diff) | |
| download | linux-426929f8d3514d7f727b8c464d1eeeaf74b21519.tar.bz2 | |
TTY: serial, use ASYNCB_CLOSING in uart_close
We need to move port->mutex locking after wait_until_sent in
uart_close (for rationale see next patches). But if we did it now, we
would introduce a race between close and open. This is exactly why
port->mutex is locked at the top of uart_close.
To avoid the race, we add ASYNCB_CLOSING to uart_close. Like every
other sane TTY driver. Thanks to tty_port_block_til_ready used in
uart_open we will have this for free. Then we can move the port->mutex
lock.
Also note that this will make the conversion to tty_port helpers
easier. They are currently handling ASYNC_CLOSING flag correctly.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Diffstat (limited to 'drivers/tty/serial/serial_core.c')
| -rw-r--r-- | drivers/tty/serial/serial_core.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/drivers/tty/serial/serial_core.c b/drivers/tty/serial/serial_core.c index 3844980b397f..849bd0d06b2c 100644 --- a/drivers/tty/serial/serial_core.c +++ b/drivers/tty/serial/serial_core.c @@ -1288,6 +1288,7 @@ static void uart_close(struct tty_struct *tty, struct file *filp) * the line discipline to only process XON/XOFF characters by * setting tty->closing. */ + set_bit(ASYNCB_CLOSING, &port->flags); tty->closing = 1; spin_unlock_irqrestore(&port->lock, flags); @@ -1335,8 +1336,10 @@ static void uart_close(struct tty_struct *tty, struct file *filp) * Wake up anyone trying to open this port. */ clear_bit(ASYNCB_NORMAL_ACTIVE, &port->flags); + clear_bit(ASYNCB_CLOSING, &port->flags); spin_unlock_irqrestore(&port->lock, flags); wake_up_interruptible(&port->open_wait); + wake_up_interruptible(&port->close_wait); done: mutex_unlock(&port->mutex); |