diff options
Diffstat (limited to 'drivers/tty/vt/vt_ioctl.c')
| -rw-r--r-- | drivers/tty/vt/vt_ioctl.c | 16 |
1 files changed, 12 insertions, 4 deletions
diff --git a/drivers/tty/vt/vt_ioctl.c b/drivers/tty/vt/vt_ioctl.c index f62f498f63c0..daf61c28ba76 100644 --- a/drivers/tty/vt/vt_ioctl.c +++ b/drivers/tty/vt/vt_ioctl.c @@ -43,9 +43,15 @@ bool vt_dont_switch; static inline bool vt_in_use(unsigned int i) { - extern struct tty_driver *console_driver; + const struct vc_data *vc = vc_cons[i].d; - return console_driver->ttys[i] && console_driver->ttys[i]->count; + /* + * console_lock must be held to prevent the vc from being deallocated + * while we're checking whether it's in-use. + */ + WARN_CONSOLE_UNLOCKED(); + + return vc && kref_read(&vc->port.kref) > 1; } static inline bool vt_busy(int i) @@ -643,15 +649,16 @@ int vt_ioctl(struct tty_struct *tty, struct vt_stat __user *vtstat = up; unsigned short state, mask; - /* Review: FIXME: Console lock ? */ if (put_user(fg_console + 1, &vtstat->v_active)) ret = -EFAULT; else { state = 1; /* /dev/tty0 is always open */ + console_lock(); /* required by vt_in_use() */ for (i = 0, mask = 2; i < MAX_NR_CONSOLES && mask; ++i, mask <<= 1) if (vt_in_use(i)) state |= mask; + console_unlock(); ret = put_user(state, &vtstat->v_state); } break; @@ -661,10 +668,11 @@ int vt_ioctl(struct tty_struct *tty, * Returns the first available (non-opened) console. */ case VT_OPENQRY: - /* FIXME: locking ? - but then this is a stupid API */ + console_lock(); /* required by vt_in_use() */ for (i = 0; i < MAX_NR_CONSOLES; ++i) if (!vt_in_use(i)) break; + console_unlock(); uival = i < MAX_NR_CONSOLES ? (i+1) : -1; goto setint; |