[PATCH 35/75] tty: relock generic_serial

Alan Cox
2009-01-02T13:46:07Z

From: Alan Cox <alan@redhat.com>

Switch generic_serial to do port count locking via the tty_port structure
ready for moving to a common port wait routine. Keep the old driver lock for
internal calling so we don't risk messing up the drivers below until we
are ready.

Still needs kref conversions

Signed-off-by: Alan Cox <alan@redhat.com>
---

drivers/char/generic_serial.c | 37 ++++++++++++++++++++++++-------------
1 files changed, 24 insertions(+), 13 deletions(-)

diff --git a/drivers/char/generic_serial.c b/drivers/char/generic_serial.c
index 2356994..2f040d1 100644
--- a/drivers/char/generic_serial.c
+++ b/drivers/char/generic_serial.c
@@ -376,7 +376,8 @@ static void gs_shutdown_port (struct gs_port *port)

void gs_hangup(struct tty_struct *tty)
{
- struct gs_port *port;
+ struct gs_port *port;
+ unsigned long flags;

func_enter ();

@@ -386,9 +387,11 @@ void gs_hangup(struct tty_struct *tty)
return;

gs_shutdown_port (port);
+ spin_lock_irqsave(&port->port.lock, flags);
port->port.flags &= ~(ASYNC_NORMAL_ACTIVE|GS_ACTIVE);
port->port.tty = NULL;
port->port.count = 0;
+ spin_unlock_irqrestore(&port->port.lock, flags);

wake_up_interruptible(&port->port.open_wait);
func_exit ();
@@ -454,12 +457,12 @@ int gs_block_til_ready(void *port_, struct file * filp)
add_wait_queue(&port->open_wait, &wait);

gs_dprintk (GS_DEBUG_BTR, "after add waitq.\n");
- spin_lock_irqsave(&gp->driver_lock, flags);
+ spin_lock_irqsave(&port->lock, flags);
if (!tty_hung_up_p(filp)) {
port->count--;
}
- spin_unlock_irqrestore(&gp->driver_lock, flags);
port->blocked_open++;
+ spin_unlock_irqrestore(&port->lock, flags);
while (1) {
CD = tty_port_carrier_raised(port);
gs_dprintk (GS_DEBUG_BTR, "CD is now %d.\n", CD);
@@ -487,16 +490,17 @@ int gs_block_til_ready(void *port_, struct file * filp)
port->blocked_open);
set_current_state (TASK_RUNNING);
remove_wait_queue(&port->open_wait, &wait);
+
+ spin_lock_irqsave(&port->lock, flags);
if (!tty_hung_up_p(filp)) {
port->count++;
}
port->blocked_open--;
- if (retval)
- return retval;
-
- port->flags |= ASYNC_NORMAL_ACTIVE;
+ if (retval == 0)
+ port->flags |= ASYNC_NORMAL_ACTIVE;
+ spin_unlock_irqrestore(&port->lock, flags);
func_exit ();
- return 0;
+ return retval;
}

@@ -517,10 +521,10 @@ void gs_close(struct tty_struct * tty, struct file * filp)
port->port.tty = tty;
}

- spin_lock_irqsave(&port->driver_lock, flags);
+ spin_lock_irqsave(&port->port.lock, flags);

if (tty_hung_up_p(filp)) {
- spin_unlock_irqrestore(&port->driver_lock, flags);
+ spin_unlock_irqrestore(&port->port.lock, flags);
if (port->rd->hungup)
port->rd->hungup (port);
func_exit ();
@@ -539,7 +543,7 @@ void gs_close(struct tty_struct * tty, struct file * filp)

if (port->port.count) {
gs_dprintk(GS_DEBUG_CLOSE, "gs_close port %p: count: %d\n", port, port->port.count);
- spin_unlock_irqrestore(&port->driver_lock, flags);
+ spin_unlock_irqrestore(&port->port.lock, flags);
func_exit ();
return;
}
@@ -560,8 +564,10 @@ void gs_close(struct tty_struct * tty, struct file * filp)
* line status register.
*/

+ spin_lock_irqsave(&port->driver_lock, flags);
port->rd->disable_rx_interrupts (port);
spin_unlock_irqrestore(&port->driver_lock, flags);
+ spin_unlock_irqrestore(&port->port.lock, flags);

/* close has no way of returning "EINTR", so discard return value */
if (port->closing_wait != ASYNC_CLOSING_WAIT_NONE)
@@ -574,20 +580,25 @@ void gs_close(struct tty_struct * tty, struct file * filp)
tty_ldisc_flush(tty);
tty->closing = 0;

+ spin_lock_irqsave(&port->driver_lock, flags);
port->event = 0;
port->rd->close (port);
port->rd->shutdown_port (port);
+ spin_unlock_irqrestore(&port->driver_lock, flags);
+
+ spin_lock_irqsave(&port->port.lock, flags);
port->port.tty = NULL;

if (port->port.blocked_open) {
if (port->close_delay) {
- spin_unlock_irqrestore(&port->driver_lock, flags);
+ spin_unlock_irqrestore(&port->port.lock, flags);
msleep_interruptible(jiffies_to_msecs(port->close_delay));
- spin_lock_irqsave(&port->driver_lock, flags);
+ spin_lock_irqsave(&port->port.lock, flags);
}
wake_up_interruptible(&port->port.open_wait);
}
port->port.flags &= ~(ASYNC_NORMAL_ACTIVE|ASYNC_CLOSING | ASYNC_INITIALIZED);
+ spin_unlock_irqrestore(&port->port.lock, flags);
wake_up_interruptible(&port->port.close_wait);

func_exit ();