tty: relock generic_serial

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>

1 files changed, 24 insertions, 13 deletions

diff --git a/drivers/char/generic_serial.c b/drivers/char/generic_serial.c
index 2356994ee010..2f040d1ed89f 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 ();