1 files changed, 41 insertions, 39 deletions

diff --git a/drivers/tty/vt/vt_ioctl.c b/drivers/tty/vt/vt_ioctl.c
index e9d9f9f3dc88..9353789e4337 100644
--- a/drivers/tty/vt/vt_ioctl.c
+++ b/drivers/tty/vt/vt_ioctl.c
@@ -38,11 +38,32 @@
 #include <linux/kbd_diacr.h>
 #include <linux/selection.h>
 
-char vt_dont_switch;
-extern struct tty_driver *console_driver;
+bool vt_dont_switch;
 
-#define VT_IS_IN_USE(i)	(console_driver->ttys[i] && console_driver->ttys[i]->count)
-#define VT_BUSY(i)	(VT_IS_IN_USE(i) || i == fg_console || vc_cons[i].d == sel_cons)
+static inline bool vt_in_use(unsigned int i)
+{
+	const struct vc_data *vc = vc_cons[i].d;
+
+	/*
+	 * 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)
+{
+	if (vt_in_use(i))
+		return true;
+	if (i == fg_console)
+		return true;
+	if (vc_is_sel(vc_cons[i].d))
+		return true;
+
+	return false;
+}
 
 /*
  * Console (vt and kd) routines, as defined by USL SVR4 manual, and by
@@ -292,16 +313,14 @@ static int vt_disallocate(unsigned int vc_num)
 	int ret = 0;
 
 	console_lock();
-	if (VT_BUSY(vc_num))
+	if (vt_busy(vc_num))
 		ret = -EBUSY;
 	else if (vc_num)
 		vc = vc_deallocate(vc_num);
 	console_unlock();
 
-	if (vc && vc_num >= MIN_NR_CONSOLES) {
-		tty_port_destroy(&vc->port);
-		kfree(vc);
-	}
+	if (vc && vc_num >= MIN_NR_CONSOLES)
+		tty_port_put(&vc->port);
 
 	return ret;
 }
@@ -314,17 +333,15 @@ static void vt_disallocate_all(void)
 
 	console_lock();
 	for (i = 1; i < MAX_NR_CONSOLES; i++)
-		if (!VT_BUSY(i))
+		if (!vt_busy(i))
 			vc[i] = vc_deallocate(i);
 		else
 			vc[i] = NULL;
 	console_unlock();
 
 	for (i = 1; i < MAX_NR_CONSOLES; i++) {
-		if (vc[i] && i >= MIN_NR_CONSOLES) {
-			tty_port_destroy(&vc[i]->port);
-			kfree(vc[i]);
-		}
+		if (vc[i] && i >= MIN_NR_CONSOLES)
+			tty_port_put(&vc[i]->port);
 	}
 }
 
@@ -338,22 +355,13 @@ int vt_ioctl(struct tty_struct *tty,
 {
 	struct vc_data *vc = tty->driver_data;
 	struct console_font_op op;	/* used in multiple places here */
-	unsigned int console;
+	unsigned int console = vc->vc_num;
 	unsigned char ucval;
 	unsigned int uival;
 	void __user *up = (void __user *)arg;
 	int i, perm;
 	int ret = 0;
 
-	console = vc->vc_num;
-
-
-	if (!vc_cons_allocated(console)) { 	/* impossible? */
-		ret = -ENOIOCTLCMD;
-		goto out;
-	}
-
-
 	/*
 	 * To have permissions to do most of the vt ioctls, we either have
 	 * to be the owner of the tty, or have CAP_SYS_TTY_CONFIG.
@@ -644,15 +652,16 @@ 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_IS_IN_USE(i))
+				if (vt_in_use(i))
 					state |= mask;
+			console_unlock();
 			ret = put_user(state, &vtstat->v_state);
 		}
 		break;
@@ -662,10 +671,11 @@ 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_IS_IN_USE(i))
+			if (!vt_in_use(i))
 				break;
+		console_unlock();
 		uival = i < MAX_NR_CONSOLES ? (i+1) : -1;
 		goto setint;		 
 
@@ -1020,12 +1030,12 @@ int vt_ioctl(struct tty_struct *tty,
 	case VT_LOCKSWITCH:
 		if (!capable(CAP_SYS_TTY_CONFIG))
 			return -EPERM;
-		vt_dont_switch = 1;
+		vt_dont_switch = true;
 		break;
 	case VT_UNLOCKSWITCH:
 		if (!capable(CAP_SYS_TTY_CONFIG))
 			return -EPERM;
-		vt_dont_switch = 0;
+		vt_dont_switch = false;
 		break;
 	case VT_GETHIFONTMASK:
 		ret = put_user(vc->vc_hi_font_mask,
@@ -1193,18 +1203,10 @@ long vt_compat_ioctl(struct tty_struct *tty,
 {
 	struct vc_data *vc = tty->driver_data;
 	struct console_font_op op;	/* used in multiple places here */
-	unsigned int console;
 	void __user *up = (void __user *)arg;
 	int perm;
 	int ret = 0;
 
-	console = vc->vc_num;
-
-	if (!vc_cons_allocated(console)) { 	/* impossible? */
-		ret = -ENOIOCTLCMD;
-		goto out;
-	}
-
 	/*
 	 * To have permissions to do most of the vt ioctls, we either have
 	 * to be the owner of the tty, or have CAP_SYS_TTY_CONFIG.
@@ -1264,7 +1266,7 @@ long vt_compat_ioctl(struct tty_struct *tty,
 		arg = (unsigned long)compat_ptr(arg);
 		goto fallback;
 	}
-out:
+
 	return ret;
 
 fallback: