diff options
Diffstat (limited to 'drivers/tty/hvc/hvc_console.c')
-rw-r--r-- | drivers/tty/hvc/hvc_console.c | 16 |
1 files changed, 14 insertions, 2 deletions
diff --git a/drivers/tty/hvc/hvc_console.c b/drivers/tty/hvc/hvc_console.c index acf6d143c753..81f23af8beca 100644 --- a/drivers/tty/hvc/hvc_console.c +++ b/drivers/tty/hvc/hvc_console.c @@ -89,6 +89,8 @@ static LIST_HEAD(hvc_structs); */ static DEFINE_SPINLOCK(hvc_structs_lock); +/* Mutex to serialize hvc_open */ +static DEFINE_MUTEX(hvc_open_mutex); /* * This value is used to assign a tty->index value to a hvc_struct based * upon order of exposure via hvc_probe(), when we can not match it to @@ -333,16 +335,24 @@ static int hvc_install(struct tty_driver *driver, struct tty_struct *tty) */ static int hvc_open(struct tty_struct *tty, struct file * filp) { - struct hvc_struct *hp = tty->driver_data; + struct hvc_struct *hp; unsigned long flags; int rc = 0; + mutex_lock(&hvc_open_mutex); + + hp = tty->driver_data; + if (!hp) { + rc = -EIO; + goto out; + } + spin_lock_irqsave(&hp->port.lock, flags); /* Check and then increment for fast path open. */ if (hp->port.count++ > 0) { spin_unlock_irqrestore(&hp->port.lock, flags); hvc_kick(); - return 0; + goto out; } /* else count == 0 */ spin_unlock_irqrestore(&hp->port.lock, flags); @@ -371,6 +381,8 @@ static int hvc_open(struct tty_struct *tty, struct file * filp) /* Force wakeup of the polling thread */ hvc_kick(); +out: + mutex_unlock(&hvc_open_mutex); return rc; } |