synclink: reworking locking a bit

Use the port mutex and port lock to fix the various races. The locking
still isn't totally consistent but its better than before. Wants switching
to the port helpers.

Signed-off-by: Alan Cox <alan@linux.intel.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 8 insertions, 1 deletions

diff --git a/drivers/char/synclinkmp.c b/drivers/char/synclinkmp.c
index 8da976bd731..ac447c7eb57 100644
--- a/drivers/char/synclinkmp.c
+++ b/drivers/char/synclinkmp.c
@@ -812,13 +812,15 @@ static void close(struct tty_struct *tty, struct file *filp)
 
         if (tty_port_close_start(&info->port, tty, filp) == 0)
                 goto cleanup;
-                
+
+        mutex_lock(&info->port.mutex);
         if (info->port.flags & ASYNC_INITIALIZED)
                 wait_until_sent(tty, info->timeout);
 
         flush_buffer(tty);
         tty_ldisc_flush(tty);
         shutdown(info);
+        mutex_unlock(&info->port.mutex);
 
         tty_port_close_end(&info->port, tty);
         info->port.tty = NULL;
@@ -834,6 +836,7 @@ cleanup:
 static void hangup(struct tty_struct *tty)
 {
         SLMP_INFO *info = tty->driver_data;
+        unsigned long flags;
 
         if (debug_level >= DEBUG_LEVEL_INFO)
                 printk("%s(%d):%s hangup()\n",
@@ -842,12 +845,16 @@ static void hangup(struct tty_struct *tty)
         if (sanity_check(info, tty->name, "hangup"))
                 return;
 
+        mutex_lock(&info->port.mutex);
         flush_buffer(tty);
         shutdown(info);
 
+        spin_lock_irqsave(&info->port.lock, flags);
         info->port.count = 0;
         info->port.flags &= ~ASYNC_NORMAL_ACTIVE;
         info->port.tty = NULL;
+        spin_unlock_irqrestore(&info->port.lock, flags);
+        mutex_unlock(&info->port.mutex);
 
         wake_up_interruptible(&info->port.open_wait);
 }