tty: relock generic_serial
Alan Cox [Fri, 2 Jan 2009 13:45:36 +0000 (13:45 +0000)]
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>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

drivers/char/generic_serial.c

index 2356994..2f040d1 100644 (file)
@@ -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 ();