fb_get_fscreeninfo(): don't bother with do_fb_ioctl()

it's easier to do the right thing directly
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

drivers/video/fbdev/core/fbmem.c

@@ -1331,22 +1331,13 @@ static int do_fscreeninfo_to_user(struct fb_fix_screeninfo *fix,
 static int fb_get_fscreeninfo(struct fb_info *info, unsigned int cmd,
 			      unsigned long arg)
 {
-	mm_segment_t old_fs;
 	struct fb_fix_screeninfo fix;
-	struct fb_fix_screeninfo32 __user *fix32;
-	int err;
-
-	fix32 = compat_ptr(arg);
-
-	old_fs = get_fs();
-	set_fs(KERNEL_DS);
-	err = do_fb_ioctl(info, cmd, (unsigned long) &fix);
-	set_fs(old_fs);
-
-	if (!err)
-		err = do_fscreeninfo_to_user(&fix, fix32);
 
-	return err;
+	if (!lock_fb_info(info))
+		return -ENODEV;
+	fix = info->fix;
+	unlock_fb_info(info);
+	return do_fscreeninfo_to_user(&fix, compat_ptr(arg));
 }
 
 static long fb_compat_ioctl(struct file *file, unsigned int cmd,