fb: rework locking to fix lock ordering on takeover
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>
Cc: stable <stable@vger.kernel.org>
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>
diff --git a/drivers/video/fbsysfs.c b/drivers/video/fbsysfs.c
index a55e366..ef476b0 100644
--- a/drivers/video/fbsysfs.c
+++ b/drivers/video/fbsysfs.c
@@ -177,6 +177,8 @@
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,
@@ -188,6 +190,7 @@
fb_destroy_modelist(&old_list);
console_unlock();
+ unlock_fb_info(fb_info);
return 0;
}