fb: rework locking to fix lock ordering on takeover
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.
[akpm@linux-foundation.org: remove stray non-ascii char, tidy comment]
[akpm@linux-foundation.org: export do_take_over_console()]
[airlied: cleanup another non-ascii char]
Signed-off-by: Alan Cox <alan@linux.intel.com>
Cc: Florian Tobias Schandinat <FlorianSchandinat@gmx.de>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Jiri Kosina <jkosina@suse.cz>
Tested-by: Sedat Dilek <sedat.dilek@gmail.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
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>
diff --git a/drivers/video/console/fbcon.c b/drivers/video/console/fbcon.c
index bdcd34d..7ccec55 100644
--- a/drivers/video/console/fbcon.c
+++ b/drivers/video/console/fbcon.c
@@ -529,6 +529,33 @@
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;
@@ -3121,7 +3148,7 @@
}
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)
diff --git a/drivers/video/fbmem.c b/drivers/video/fbmem.c
index c6ce416..f04ccf7 100644
--- a/drivers/video/fbmem.c
+++ b/drivers/video/fbmem.c
@@ -1642,7 +1642,9 @@
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;
}
@@ -1845,11 +1847,8 @@
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;
diff --git a/drivers/video/fbsysfs.c b/drivers/video/fbsysfs.c
index 67afa9c..303fb9f 100644
--- a/drivers/video/fbsysfs.c
+++ b/drivers/video/fbsysfs.c
@@ -175,6 +175,8 @@
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 @@
fb_destroy_modelist(&old_list);
console_unlock();
+ unlock_fb_info(fb_info);
return 0;
}