fb: Yet another band-aid for fixing lockdep mess

commit e93a9a868792ad71cdd09d75e5a02d8067473c4e upstream.

I've still got lockdep warnings even after Alan's patch, and it seems that
yet more band aids are required to paper over similar paths for
unbind_con_driver() and unregister_con_driver().  After this hack, lockdep
warnings are finally gone.

Signed-off-by: Takashi Iwai <tiwai@suse.de>
Cc: Alan Cox <alan@linux.intel.com>
Cc: Florian Tobias Schandinat <FlorianSchandinat@gmx.de>
Cc: Jiri Kosina <jkosina@suse.cz>
Tested-by: Sedat Dilek <sedat.dilek@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Dave Airlie <airlied@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

5 files changed, 37 insertions, 17 deletions

diff --git a/drivers/tty/vt/vt.c b/drivers/tty/vt/vt.c
index 4fa5dd6efb4b..3b1d6bf349c2 100644
--- a/drivers/tty/vt/vt.c
+++ b/drivers/tty/vt/vt.c
@@ -3135,6 +3135,18 @@ static int con_is_graphics(const struct consw *csw, int first, int last)
  */
 int unbind_con_driver(const struct consw *csw, int first, int last, int deflt)
 {
+	int retval;
+
+	console_lock();
+	retval = do_unbind_con_driver(csw, first, last, deflt);
+	console_unlock();
+	return retval;
+}
+EXPORT_SYMBOL(unbind_con_driver);
+
+/* unlocked version of unbind_con_driver() */
+int do_unbind_con_driver(const struct consw *csw, int first, int last, int deflt)
+{
 	struct module *owner = csw->owner;
 	const struct consw *defcsw = NULL;
 	struct con_driver *con_driver = NULL, *con_back = NULL;
@@ -3143,7 +3155,7 @@ int unbind_con_driver(const struct consw *csw, int first, int last, int deflt)
 	if (!try_module_get(owner))
 		return -ENODEV;
 
-	console_lock();
+	WARN_CONSOLE_UNLOCKED();
 
 	/* check if driver is registered and if it is unbindable */
 	for (i = 0; i < MAX_NR_CON_DRIVER; i++) {
@@ -3156,10 +3168,8 @@ int unbind_con_driver(const struct consw *csw, int first, int last, int deflt)
 		}
 	}
 
-	if (retval) {
-		console_unlock();
+	if (retval)
 		goto err;
-	}
 
 	retval = -ENODEV;
 
@@ -3175,15 +3185,11 @@ int unbind_con_driver(const struct consw *csw, int first, int last, int deflt)
 		}
 	}
 
-	if (retval) {
-		console_unlock();
+	if (retval)
 		goto err;
-	}
 
-	if (!con_is_bound(csw)) {
-		console_unlock();
+	if (!con_is_bound(csw))
 		goto err;
-	}
 
 	first = max(first, con_driver->first);
 	last = min(last, con_driver->last);
@@ -3212,13 +3218,12 @@ int unbind_con_driver(const struct consw *csw, int first, int last, int deflt)
 
 	/* ignore return value, binding should not fail */
 	do_bind_con_driver(defcsw, first, last, deflt);
-	console_unlock();
 err:
 	module_put(owner);
 	return retval;
 
 }
-EXPORT_SYMBOL(unbind_con_driver);
+EXPORT_SYMBOL_GPL(do_unbind_con_driver);
 
 static int vt_bind(struct con_driver *con)
 {
@@ -3605,9 +3610,18 @@ EXPORT_SYMBOL(register_con_driver);
  */
 int unregister_con_driver(const struct consw *csw)
 {
-	int i, retval = -ENODEV;
+	int retval;
 
 	console_lock();
+	retval = do_unregister_con_driver(csw);
+	console_unlock();
+	return retval;
+}
+EXPORT_SYMBOL(unregister_con_driver);
+
+int do_unregister_con_driver(const struct consw *csw)
+{
+	int i, retval = -ENODEV;
 
 	/* cannot unregister a bound driver */
 	if (con_is_bound(csw))
@@ -3633,10 +3647,9 @@ int unregister_con_driver(const struct consw *csw)
 		}
 	}
 err:
-	console_unlock();
 	return retval;
 }
-EXPORT_SYMBOL(unregister_con_driver);
+EXPORT_SYMBOL_GPL(do_unregister_con_driver);
 
 /*
  *	If we support more console drivers, this function is used
diff --git a/drivers/video/console/fbcon.c b/drivers/video/console/fbcon.c
index f06719f5645e..0d4c192b1969 100644
--- a/drivers/video/console/fbcon.c
+++ b/drivers/video/console/fbcon.c
@@ -3010,7 +3010,7 @@ static int fbcon_unbind(void)
 {
 	int ret;
 
-	ret = unbind_con_driver(&fb_con, first_fb_vc, last_fb_vc,
+	ret = do_unbind_con_driver(&fb_con, first_fb_vc, last_fb_vc,
 				fbcon_is_default);
 
 	if (!ret)
@@ -3083,7 +3083,7 @@ static int fbcon_fb_unregistered(struct fb_info *info)
 		primary_device = -1;
 
 	if (!num_registered_fb)
-		unregister_con_driver(&fb_con);
+		do_unregister_con_driver(&fb_con);
 
 	return 0;
 }
diff --git a/drivers/video/fbmem.c b/drivers/video/fbmem.c
index d8d9831b3fdb..070b9a13d892 100644
--- a/drivers/video/fbmem.c
+++ b/drivers/video/fbmem.c
@@ -1668,8 +1668,10 @@ static int do_unregister_framebuffer(struct fb_info *fb_info)
 
 	if (!lock_fb_info(fb_info))
 		return -ENODEV;
+	console_lock();
 	event.info = fb_info;
 	ret = fb_notifier_call_chain(FB_EVENT_FB_UNBIND, &event);
+	console_unlock();
 	unlock_fb_info(fb_info);
 
 	if (ret)
@@ -1684,7 +1686,9 @@ static int do_unregister_framebuffer(struct fb_info *fb_info)
 	num_registered_fb--;
 	fb_cleanup_device(fb_info);
 	event.info = fb_info;
+	console_lock();
 	fb_notifier_call_chain(FB_EVENT_FB_UNREGISTERED, &event);
+	console_unlock();
 
 	/* this may free fb info */
 	put_fb_info(fb_info);
diff --git a/include/linux/console.h b/include/linux/console.h
index 4ef4307dfb82..47b858cffc47 100644
--- a/include/linux/console.h
+++ b/include/linux/console.h
@@ -77,6 +77,7 @@ extern const struct consw prom_con;	/* SPARC PROM console */
 int con_is_bound(const struct consw *csw);
 int register_con_driver(const struct consw *csw, int first, int last);
 int unregister_con_driver(const struct consw *csw);
+int do_unregister_con_driver(const struct consw *csw);
 int take_over_console(const struct consw *sw, int first, int last, int deflt);
 int do_take_over_console(const struct consw *sw, int first, int last, int deflt);
 void give_up_console(const struct consw *sw);
diff --git a/include/linux/vt_kern.h b/include/linux/vt_kern.h
index 1f55665d7b49..e8d65718560b 100644
--- a/include/linux/vt_kern.h
+++ b/include/linux/vt_kern.h
@@ -131,6 +131,8 @@ void vt_event_post(unsigned int event, unsigned int old, unsigned int new);
 int vt_waitactive(int n);
 void change_console(struct vc_data *new_vc);
 void reset_vc(struct vc_data *vc);
+extern int do_unbind_con_driver(const struct consw *csw, int first, int last,
+			     int deflt);
 extern int unbind_con_driver(const struct consw *csw, int first, int last,
 			     int deflt);
 int vty_init(const struct file_operations *console_fops);