3.2-stable review patch. If anyone has any objections, please let me know.
------------------
From: Alan Cox <a...@linux.intel.com>
commit 50e244cc793d511b86adea24972f3a7264cae114 upstream.
Adjust the console layer to allow a take over call where the caller
already holds the locks. Make the fb layer lock in order.
This is partly a band aid, the fb layer is terminally confused about the
locking rules it uses for its notifiers it seems.
[a...@linux-foundation.org: remove stray non-ascii char, tidy comment]
[a...@linux-foundation.org: export do_take_over_console()]
[airlied: cleanup another non-ascii char]
Signed-off-by: Alan Cox <a...@linux.intel.com>
Cc: Florian Tobias Schandinat <florianschandi...@gmx.de>
Cc: Stephen Rothwell <s...@canb.auug.org.au>
Cc: Jiri Kosina <jkos...@suse.cz>
Tested-by: Sedat Dilek <sedat.di...@gmail.com>
Reviewed-by: Daniel Vetter <daniel.vet...@ffwll.ch>
Signed-off-by: Andrew Morton <a...@linux-foundation.org>
Signed-off-by: Dave Airlie <airl...@redhat.com>
Signed-off-by: Ben Hutchings <b...@decadent.org.uk>
---
drivers/tty/vt/vt.c | 93 +++++++++++++++++++++++++++++++----------
drivers/video/console/fbcon.c | 29 ++++++++++++-
drivers/video/fbmem.c | 5 +--
drivers/video/fbsysfs.c | 3 ++
include/linux/console.h | 1 +
5 files changed, 104 insertions(+), 27 deletions(-)
--- a/drivers/tty/vt/vt.c
+++ b/drivers/tty/vt/vt.c
@@ -3016,7 +3016,7 @@ int __init vty_init(const struct file_op
static struct class *vtconsole_class;
-static int bind_con_driver(const struct consw *csw, int first, int last,
+static int do_bind_con_driver(const struct consw *csw, int first, int last,
int deflt)
{
struct module *owner = csw->owner;
@@ -3027,7 +3027,7 @@ static int bind_con_driver(const struct
if (!try_module_get(owner))
return -ENODEV;
- console_lock();
+ WARN_CONSOLE_UNLOCKED();
/* check if driver is registered */
for (i = 0; i < MAX_NR_CON_DRIVER; i++) {
@@ -3112,11 +3112,22 @@ static int bind_con_driver(const struct
retval = 0;
err:
- console_unlock();
module_put(owner);
return retval;
};
+
+static int bind_con_driver(const struct consw *csw, int first, int last,
+ int deflt)
+{
+ int ret;
+
+ console_lock();
+ ret = do_bind_con_driver(csw, first, last, deflt);
+ console_unlock();
+ return ret;
+}
+
#ifdef CONFIG_VT_HW_CONSOLE_BINDING
static int con_is_graphics(const struct consw *csw, int first, int last)
{
@@ -3228,9 +3239,9 @@ int unbind_con_driver(const struct consw
if (!con_is_bound(csw))
con_driver->flag &= ~CON_DRIVER_FLAG_INIT;
- console_unlock();
/* ignore return value, binding should not fail */
- bind_con_driver(defcsw, first, last, deflt);
+ do_bind_con_driver(defcsw, first, last, deflt);
+ console_unlock();
err:
module_put(owner);
return retval;
@@ -3508,28 +3519,18 @@ int con_debug_leave(void)
}
EXPORT_SYMBOL_GPL(con_debug_leave);
-/**
- * register_con_driver - register console driver to console layer
- * @csw: console driver
- * @first: the first console to take over, minimum value is 0
- * @last: the last console to take over, maximum value is MAX_NR_CONSOLES -1
- *
- * DESCRIPTION: This function registers a console driver which can later
- * bind to a range of consoles specified by @first and @last. It will
- * also initialize the console driver by calling con_startup().
- */
-int register_con_driver(const struct consw *csw, int first, int last)
+static int do_register_con_driver(const struct consw *csw, int first, int last)
{
struct module *owner = csw->owner;
struct con_driver *con_driver;
const char *desc;
int i, retval = 0;
+ WARN_CONSOLE_UNLOCKED();
+
if (!try_module_get(owner))
return -ENODEV;
- console_lock();
-
for (i = 0; i < MAX_NR_CON_DRIVER; i++) {
con_driver = ®istered_con_driver[i];
@@ -3582,10 +3583,29 @@ int register_con_driver(const struct con
}
err:
- console_unlock();
module_put(owner);
return retval;
}
+
+/**
+ * register_con_driver - register console driver to console layer
+ * @csw: console driver
+ * @first: the first console to take over, minimum value is 0
+ * @last: the last console to take over, maximum value is MAX_NR_CONSOLES -1
+ *
+ * DESCRIPTION: This function registers a console driver which can later
+ * bind to a range of consoles specified by @first and @last. It will
+ * also initialize the console driver by calling con_startup().
+ */
+int register_con_driver(const struct consw *csw, int first, int last)
+{
+ int retval;
+
+ console_lock();
+ retval = do_register_con_driver(csw, first, last);
+ console_unlock();
+ return retval;
+}
EXPORT_SYMBOL(register_con_driver);
/**
@@ -3639,17 +3659,44 @@ EXPORT_SYMBOL(unregister_con_driver);
* when a driver wants to take over some existing consoles
* and become default driver for newly opened ones.
*
- * take_over_console is basically a register followed by unbind
+ * take_over_console is basically a register followed by unbind
+ */
+int do_take_over_console(const struct consw *csw, int first, int last, int
deflt)
+{
+ int err;
+
+ err = do_register_con_driver(csw, first, last);
+ /*
+ * If we get an busy error we still want to bind the console driver
+ * and return success, as we may have unbound the console driver
+ * but not unregistered it.
+ */
+ if (err == -EBUSY)
+ err = 0;
+ if (!err)
+ do_bind_con_driver(csw, first, last, deflt);
+
+ return err;
+}
+EXPORT_SYMBOL_GPL(do_take_over_console);
+
+/*
+ * If we support more console drivers, this function is used
+ * when a driver wants to take over some existing consoles
+ * and become default driver for newly opened ones.
+ *
+ * take_over_console is basically a register followed by unbind
*/
int take_over_console(const struct consw *csw, int first, int last, int deflt)
{
int err;
err = register_con_driver(csw, first, last);
- /* if we get an busy error we still want to bind the console driver
+ /*
+ * If we get an busy error we still want to bind the console driver
* and return success, as we may have unbound the console driver
- Â * but not unregistered it.
- */
+ * but not unregistered it.
+ */
if (err == -EBUSY)
err = 0;
if (!err)
--- a/drivers/video/console/fbcon.c
+++ b/drivers/video/console/fbcon.c
@@ -530,6 +530,33 @@ static int search_for_mapped_con(void)
return retval;
}
+static int do_fbcon_takeover(int show_logo)
+{
+ int err, i;
+
+ if (!num_registered_fb)
+ return -ENODEV;
+
+ if (!show_logo)
+ logo_shown = FBCON_LOGO_DONTSHOW;
+
+ for (i = first_fb_vc; i <= last_fb_vc; i++)
+ con2fb_map[i] = info_idx;
+
+ err = do_take_over_console(&fb_con, first_fb_vc, last_fb_vc,
+ fbcon_is_default);
+
+ if (err) {
+ for (i = first_fb_vc; i <= last_fb_vc; i++)
+ con2fb_map[i] = -1;
+ info_idx = -1;
+ } else {
+ fbcon_has_console_bind = 1;
+ }
+
+ return err;
+}
+
static int fbcon_takeover(int show_logo)
{
int err, i;
@@ -3122,7 +3149,7 @@ static int fbcon_fb_registered(struct fb
}
if (info_idx != -1)
- ret = fbcon_takeover(1);
+ ret = do_fbcon_takeover(1);
} else {
for (i = first_fb_vc; i <= last_fb_vc; i++) {
if (con2fb_map_boot[i] == idx)
--- a/drivers/video/fbmem.c
+++ b/drivers/video/fbmem.c
@@ -1628,7 +1628,9 @@ static int do_register_framebuffer(struc
event.info = fb_info;
if (!lock_fb_info(fb_info))
return -ENODEV;
+ console_lock();
fb_notifier_call_chain(FB_EVENT_FB_REGISTERED, &event);
+ console_unlock();
unlock_fb_info(fb_info);
return 0;
}
@@ -1831,11 +1833,8 @@ int fb_new_modelist(struct fb_info *info
err = 1;
if (!list_empty(&info->modelist)) {
- if (!lock_fb_info(info))
- return -ENODEV;
event.info = info;
err = fb_notifier_call_chain(FB_EVENT_NEW_MODELIST, &event);
- unlock_fb_info(info);
}
return err;
--- a/drivers/video/fbsysfs.c
+++ b/drivers/video/fbsysfs.c
@@ -175,6 +175,8 @@ static ssize_t store_modes(struct device
if (i * sizeof(struct fb_videomode) != count)
return -EINVAL;
+ if (!lock_fb_info(fb_info))
+ return -ENODEV;
console_lock();
list_splice(&fb_info->modelist, &old_list);
fb_videomode_to_modelist((const struct fb_videomode *)buf, i,
@@ -186,6 +188,7 @@ static ssize_t store_modes(struct device
fb_destroy_modelist(&old_list);
console_unlock();
+ unlock_fb_info(fb_info);
return 0;
}
--- a/include/linux/console.h
+++ b/include/linux/console.h
@@ -78,6 +78,7 @@ 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 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);
#ifdef CONFIG_HW_CONSOLE
int con_debug_enter(struct vc_data *vc);
--
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