Patchwork [3.5.y.z,extended,stable] Patch "fb: Yet another band-aid for fixing lockdep mess" has been added to staging queue

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Submitter Luis Henriques
Date Feb. 28, 2013, 11:58 a.m.
Message ID <1362052681-19556-1-git-send-email-luis.henriques@canonical.com>
Download mbox | patch
Permalink /patch/223915/
State New
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Comments

Luis Henriques - Feb. 28, 2013, 11:58 a.m.
This is a note to let you know that I have just added a patch titled

    fb: Yet another band-aid for fixing lockdep mess

to the linux-3.5.y-queue branch of the 3.5.y.z extended stable tree 
which can be found at:

 http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.5.y-queue

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.5.y.z tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Luis

------

From 5790858214c40c1683cf9a49ccb9f34bd15c9da2 Mon Sep 17 00:00:00 2001
From: Takashi Iwai <tiwai@suse.de>
Date: Fri, 25 Jan 2013 10:28:18 +1000
Subject: [PATCH] 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: Luis Henriques <luis.henriques@canonical.com>
---
 drivers/tty/vt/vt.c           | 43 ++++++++++++++++++++++++++++---------------
 drivers/video/console/fbcon.c |  4 ++--
 drivers/video/fbmem.c         |  4 ++++
 include/linux/console.h       |  1 +
 include/linux/vt_kern.h       |  2 ++
 5 files changed, 37 insertions(+), 17 deletions(-)

--
1.8.1.2

Patch

diff --git a/drivers/tty/vt/vt.c b/drivers/tty/vt/vt.c
index f7ffae5..d2f0b26 100644
--- a/drivers/tty/vt/vt.c
+++ b/drivers/tty/vt/vt.c
@@ -3165,6 +3165,18 @@  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;
@@ -3173,7 +3185,7 @@  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++) {
@@ -3186,10 +3198,8 @@  int unbind_con_driver(const struct consw *csw, int first, int last, int deflt)
 		}
 	}

-	if (retval) {
-		console_unlock();
+	if (retval)
 		goto err;
-	}

 	retval = -ENODEV;

@@ -3205,15 +3215,11 @@  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);
@@ -3242,13 +3248,12 @@  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)
 {
@@ -3635,9 +3640,18 @@  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))
@@ -3663,10 +3677,9 @@  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 7ccec55..5bf163e 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 616278a..afa804f 100644
--- a/drivers/video/fbmem.c
+++ b/drivers/video/fbmem.c
@@ -1669,8 +1669,10 @@  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)
@@ -1685,7 +1687,9 @@  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 e8ea7d7..f59e942 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 1f55665..e8d6571 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);