sisfb: use display information in info not in var for panning

We must not use any information in the passed var besides xoffset,
yoffset and vmode as otherwise applications might abuse it.

Fix checkpatch.pl warnings in the surrounding code.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Cc: Aaro Koskinen <aaro.koskinen@iki.fi>
Cc: Thomas Winischhofer <thomas@winischhofer.net>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>

diff --git a/drivers/video/sis/sis_main.c b/drivers/video/sis/sis_main.c
index 75259845933deb53ab030a2067bb52e69259f673..078ca2167d6f9754a3fc9ad26582643b82e34c8a 100644 (file)
--- a/drivers/video/sis/sis_main.c
+++ b/drivers/video/sis/sis_main.c
@@ -1333,19 +1333,14 @@ sisfb_set_base_CRT2(struct sis_video_info *ivideo, unsigned int base)
 }
 
 static int
-sisfb_pan_var(struct sis_video_info *ivideo, struct fb_var_screeninfo *var)
+sisfb_pan_var(struct sis_video_info *ivideo, struct fb_info *info,
+             struct fb_var_screeninfo *var)
 {
-       if(var->xoffset > (var->xres_virtual - var->xres)) {
-               return -EINVAL;
-       }
-       if(var->yoffset > (var->yres_virtual - var->yres)) {
-               return -EINVAL;
-       }
-
-       ivideo->current_base = (var->yoffset * var->xres_virtual) + var->xoffset;
+       ivideo->current_base = var->yoffset * info->var.xres_virtual
+                            + var->xoffset;
 
        /* calculate base bpp dep. */
-       switch(var->bits_per_pixel) {
+       switch (info->var.bits_per_pixel) {
        case 32:
                break;
        case 16:
@@ -1635,20 +1630,15 @@ sisfb_pan_display(struct fb_var_screeninfo *var, struct fb_info* info)
        struct sis_video_info *ivideo = (struct sis_video_info *)info->par;
        int err;
 
-       if(var->xoffset > (var->xres_virtual - var->xres))
-               return -EINVAL;
-
-       if(var->yoffset > (var->yres_virtual - var->yres))
-               return -EINVAL;
-
-       if(var->vmode & FB_VMODE_YWRAP)
+       if (var->vmode & FB_VMODE_YWRAP)
                return -EINVAL;
 
-       if(var->xoffset + info->var.xres > info->var.xres_virtual ||
-          var->yoffset + info->var.yres > info->var.yres_virtual)
+       if (var->xoffset + info->var.xres > info->var.xres_virtual ||
+           var->yoffset + info->var.yres > info->var.yres_virtual)
                return -EINVAL;
 
-       if((err = sisfb_pan_var(ivideo, var)) < 0)
+       err = sisfb_pan_var(ivideo, info, var);
+       if (err < 0)
                return err;
 
        info->var.xoffset = var->xoffset;