amifb: test virtual screen range before subtraction on unsigned

[linux-2.6-omap-h63xx.git] / drivers / video / amifb.c

diff --git a/drivers/video/amifb.c b/drivers/video/amifb.c
index 45c154ade9ca4901710716356f02abdcd336929c..0c549aa1cf87fc306e20e00e8dab38f08c885ff5 100644 (file)
--- a/drivers/video/amifb.c
+++ b/drivers/video/amifb.c
@@ -2048,13 +2048,16 @@ static void amifb_copyarea(struct fb_info *info,
        width = x2 - dx;
        height = y2 - dy;
 
+       if (area->sx + dx < area->dx || area->sy + dy < area->dy)
+               return;
+
        /* update sx,sy */
        sx = area->sx + (dx - area->dx);
        sy = area->sy + (dy - area->dy);
 
        /* the source must be completely inside the virtual screen */
-       if (sx < 0 || sy < 0 || (sx + width) > info->var.xres_virtual ||
-           (sy + height) > info->var.yres_virtual)
+       if (sx + width > info->var.xres_virtual ||
+                       sy + height > info->var.yres_virtual)
                return;
 
        if (dy > sy || (dy == sy && dx > sx)) {