TTY: HVC, use count from tty_port

Now, count is used from tty_port and protected by tty_port->lock.

n_outbuf is left unprotected in hvc_hangup now, because there is no
point to hold any lock, since other uses are unprotected too.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Cc: linuxppc-dev@lists.ozlabs.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

2 files changed, 21 insertions, 20 deletions

diff --git a/drivers/tty/hvc/hvc_console.c b/drivers/tty/hvc/hvc_console.c
index 92b7f5d5441f..6c45cbf3fc91 100644
--- a/drivers/tty/hvc/hvc_console.c
+++ b/drivers/tty/hvc/hvc_console.c
@@ -313,18 +313,18 @@ static int hvc_open(struct tty_struct *tty, struct file * filp)
         if (!(hp = hvc_get_by_index(tty->index)))
                 return -ENODEV;
 
-        spin_lock_irqsave(&hp->lock, flags);
+        spin_lock_irqsave(&hp->port.lock, flags);
         /* Check and then increment for fast path open. */
-        if (hp->count++ > 0) {
+        if (hp->port.count++ > 0) {
+                spin_unlock_irqrestore(&hp->port.lock, flags);
+                /* FIXME why taking a reference here? */
                 tty_kref_get(tty);
-                spin_unlock_irqrestore(&hp->lock, flags);
                 hvc_kick();
                 return 0;
         } /* else count == 0 */
+        spin_unlock_irqrestore(&hp->port.lock, flags);
 
         tty->driver_data = hp;
-        spin_unlock_irqrestore(&hp->lock, flags);
-
         tty_port_tty_set(&hp->port, tty);
 
         if (hp->ops->notifier_add)
@@ -367,10 +367,10 @@ static void hvc_close(struct tty_struct *tty, struct file * filp)
 
         hp = tty->driver_data;
 
-        spin_lock_irqsave(&hp->lock, flags);
+        spin_lock_irqsave(&hp->port.lock, flags);
 
-        if (--hp->count == 0) {
-                spin_unlock_irqrestore(&hp->lock, flags);
+        if (--hp->port.count == 0) {
+                spin_unlock_irqrestore(&hp->port.lock, flags);
                 /* We are done with the tty pointer now. */
                 tty_port_tty_set(&hp->port, NULL);
 
@@ -387,10 +387,10 @@ static void hvc_close(struct tty_struct *tty, struct file * filp)
                  */
                 tty_wait_until_sent_from_close(tty, HVC_CLOSE_WAIT);
         } else {
-                if (hp->count < 0)
+                if (hp->port.count < 0)
                         printk(KERN_ERR "hvc_close %X: oops, count is %d\n",
-                                hp->vtermno, hp->count);
-                spin_unlock_irqrestore(&hp->lock, flags);
+                                hp->vtermno, hp->port.count);
+                spin_unlock_irqrestore(&hp->port.lock, flags);
         }
 
         tty_kref_put(tty);
@@ -409,24 +409,25 @@ static void hvc_hangup(struct tty_struct *tty)
         /* cancel pending tty resize work */
         cancel_work_sync(&hp->tty_resize);
 
-        spin_lock_irqsave(&hp->lock, flags);
+        spin_lock_irqsave(&hp->port.lock, flags);
 
         /*
          * The N_TTY line discipline has problems such that in a close vs
          * open->hangup case this can be called after the final close so prevent
          * that from happening for now.
          */
-        if (hp->count <= 0) {
-                spin_unlock_irqrestore(&hp->lock, flags);
+        if (hp->port.count <= 0) {
+                spin_unlock_irqrestore(&hp->port.lock, flags);
                 return;
         }
 
-        temp_open_count = hp->count;
-        hp->count = 0;
-        hp->n_outbuf = 0;
-        spin_unlock_irqrestore(&hp->lock, flags);
+        temp_open_count = hp->port.count;
+        hp->port.count = 0;
+        spin_unlock_irqrestore(&hp->port.lock, flags);
         tty_port_tty_set(&hp->port, NULL);
 
+        hp->n_outbuf = 0;
+
         if (hp->ops->notifier_hangup)
                 hp->ops->notifier_hangup(hp, hp->data);
 
@@ -474,7 +475,8 @@ static int hvc_write(struct tty_struct *tty, const unsigned char *buf, int count
         if (!hp)
                 return -EPIPE;
 
-        if (hp->count <= 0)
+        /* FIXME what's this (unprotected) check for? */
+        if (hp->port.count <= 0)
                 return -EIO;
 
         spin_lock_irqsave(&hp->lock, flags);
diff --git a/drivers/tty/hvc/hvc_console.h b/drivers/tty/hvc/hvc_console.h
index 594a28fe0da0..674d23cb919a 100644
--- a/drivers/tty/hvc/hvc_console.h
+++ b/drivers/tty/hvc/hvc_console.h
@@ -49,7 +49,6 @@ struct hvc_struct {
         struct tty_port port;
         spinlock_t lock;
         int index;
-        int count;
         int do_wakeup;
         char *outbuf;
         int outbuf_size;