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Message-Id: <20130304033711.235458785@decadent.org.uk>
Date: Mon, 04 Mar 2013 03:37:44 +0000
From: Ben Hutchings <ben@...adent.org.uk>
To: linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc: akpm@...ux-foundation.org, Takashi Iwai <tiwai@...e.de>,
Alan Cox <alan@...ux.intel.com>,
Florian Tobias Schandinat <FlorianSchandinat@....de>,
Jiri Kosina <jkosina@...e.cz>,
Sedat Dilek <sedat.dilek@...il.com>,
Dave Airlie <airlied@...hat.com>
Subject: [ 037/153] fb: Yet another band-aid for fixing lockdep mess
3.2-stable review patch. If anyone has any objections, please let me know.
------------------
From: Takashi Iwai <tiwai@...e.de>
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@...e.de>
Cc: Alan Cox <alan@...ux.intel.com>
Cc: Florian Tobias Schandinat <FlorianSchandinat@....de>
Cc: Jiri Kosina <jkosina@...e.cz>
Tested-by: Sedat Dilek <sedat.dilek@...il.com>
Signed-off-by: Andrew Morton <akpm@...ux-foundation.org>
Signed-off-by: Dave Airlie <airlied@...hat.com>
Signed-off-by: Ben Hutchings <ben@...adent.org.uk>
---
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(-)
--- a/drivers/tty/vt/vt.c
+++ b/drivers/tty/vt/vt.c
@@ -3164,6 +3164,18 @@ static int con_is_graphics(const struct
*/
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;
@@ -3172,7 +3184,7 @@ int unbind_con_driver(const struct consw
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++) {
@@ -3185,10 +3197,8 @@ int unbind_con_driver(const struct consw
}
}
- if (retval) {
- console_unlock();
+ if (retval)
goto err;
- }
retval = -ENODEV;
@@ -3204,15 +3214,11 @@ int unbind_con_driver(const struct consw
}
}
- 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);
@@ -3241,13 +3247,12 @@ int unbind_con_driver(const struct consw
/* 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)
{
@@ -3621,9 +3626,18 @@ 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))
@@ -3649,10 +3663,9 @@ int unregister_con_driver(const struct c
}
}
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
--- a/drivers/video/console/fbcon.c
+++ b/drivers/video/console/fbcon.c
@@ -3011,7 +3011,7 @@ 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)
@@ -3084,7 +3084,7 @@ static int fbcon_fb_unregistered(struct
primary_device = -1;
if (!num_registered_fb)
- unregister_con_driver(&fb_con);
+ do_unregister_con_driver(&fb_con);
return 0;
}
--- a/drivers/video/fbmem.c
+++ b/drivers/video/fbmem.c
@@ -1646,8 +1646,10 @@ static int do_unregister_framebuffer(str
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)
@@ -1662,7 +1664,9 @@ static int do_unregister_framebuffer(str
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);
--- a/include/linux/console.h
+++ b/include/linux/console.h
@@ -77,6 +77,7 @@ extern const struct consw prom_con; /* S
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);
--- a/include/linux/vt_kern.h
+++ b/include/linux/vt_kern.h
@@ -132,6 +132,8 @@ void vt_event_post(unsigned int event, u
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);
--
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