[PATCH v2 30/38] fbdev/smscufx: Detect registered fb_info from refcount

[Thomas Zimmermann]

Detect registered instances of fb_info by reading the reference
counter from struct fb_info.read. Avoids looking at the dev field
and prepares fbdev for making struct fb_info.dev optional.

Signed-off-by: Thomas Zimmermann <tzimmermann@xxxxxxx>
Cc: Steve Glendinning <steve.glendinning@xxxxxxxxxxx>
Reviewed-by: Javier Martinez Canillas <javierm@xxxxxxxxxx>
---
 drivers/video/fbdev/smscufx.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/video/fbdev/smscufx.c b/drivers/video/fbdev/smscufx.c
index 17cec62cc65db..adb2b1fe8383c 100644
--- a/drivers/video/fbdev/smscufx.c
+++ b/drivers/video/fbdev/smscufx.c
@@ -1496,7 +1496,7 @@ static int ufx_setup_modes(struct ufx_data *dev, struct fb_info *info,
 	u8 *edid;
 	int i, result = 0, tries = 3;
 
-	if (info->dev) /* only use mutex if info has been registered */
+	if (refcount_read(&info->count)) /* only use mutex if info has been registered */
 		mutex_lock(&info->lock);
 
 	edid = kmalloc(EDID_LENGTH, GFP_KERNEL);
@@ -1610,7 +1610,7 @@ static int ufx_setup_modes(struct ufx_data *dev, struct fb_info *info,
 	if (edid && (dev->edid != edid))
 		kfree(edid);
 
-	if (info->dev)
+	if (refcount_read(&info->count))
 		mutex_unlock(&info->lock);
 
 	return result;
-- 
2.41.0