Re: [PATCH] fix warning in fbmem.c

[Jesper Juhl]

On Thu, 17 Jun 2004, Geert Uytterhoeven wrote:

> On Thu, 17 Jun 2004, Jesper Juhl wrote:
> > Here are two proposed patches to fix the following warning in fbmem.c :
> > drivers/video/fbmem.c:933: warning: passing arg 1 of `copy_from_user' discards qualifiers from pointer target type
> >
> > The cause of the warning is that the .data member of struct fb_image is of
> > type 'const char *' and copy_from_user() takes a 'void *' as it's first
> > 'to' argument.
> > I see two ways to fix it;
> > a) use a simple cast to hide the warning
> > b) rewrite the code to copy into a buffer pointed to by a non-const
> > pointer, then assign the pointer to cursor.image.data
>
> Here is a variant of b, which avoids the cast and makes cursor.mask const as
> well.
>

> --- linux-2.6.7-rc1/include/linux/fb.h.orig	2004-05-24 11:14:01.000000000 +0200
> +++ linux-2.6.7-rc1/include/linux/fb.h	2004-06-07 22:38:01.000000000 +0200
> @@ -375,7 +375,7 @@ struct fb_cursor {
>  	__u16 set;		/* what to set */
>  	__u16 enable;		/* cursor on/off */
>  	__u16 rop;		/* bitop operation */
> -	char *mask;		/* cursor mask bits */
> +	const char *mask;	/* cursor mask bits */
>  	struct fbcurpos hot;	/* cursor hot spot */
>  	struct fb_image	image;	/* Cursor image */
>  };
>

Nice. I didn't know the code well enough to dare make this change as well.


--
Jesper Juhl <juhl-lkml@xxxxxx>
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