On Thu, Mar 1, 2012 at 20:22, Daniel Vetter <daniel.vetter at ffwll.ch> wrote:
> +/* Multipage variants of the above prefault helpers, useful if more than
> + * PAGE_SIZE of date needs to be prefaulted. These are separate from the
> above
> + * functions (which only handle up to PAGE_SIZE) to avoid clobbering the
> + * filemap.c hotpaths. */
> +static inline int fault_in_multipages_writeable(char __user *uaddr, int size)
> +{
> + ? ? ? int ret;
> + ? ? ? const char __user *end = uaddr + size - 1;
Please drop the const.
> +
> + ? ? ? if (unlikely(size == 0))
> + ? ? ? ? ? ? ? return 0;
> +
> + ? ? ? /*
> + ? ? ? ?* Writing zeroes into userspace here is OK, because we know that if
> + ? ? ? ?* the zero gets there, we'll be overwriting it.
> + ? ? ? ?*/
> + ? ? ? while (uaddr <= end) {
> + ? ? ? ? ? ? ? ret = __put_user(0, uaddr);
> + ? ? ? ? ? ? ? if (ret != 0)
> + ? ? ? ? ? ? ? ? ? ? ? return ret;
> + ? ? ? ? ? ? ? uaddr += PAGE_SIZE;
> + ? ? ? }
> +
> + ? ? ? /* Check whether the range spilled into the next page. */
> + ? ? ? if (((unsigned long)uaddr & PAGE_MASK) ==
> + ? ? ? ? ? ? ? ? ? ? ? ((unsigned long)end & PAGE_MASK))
> + ? ? ? ? ? ? ? ret = __put_user(0, end);
include/linux/pagemap.h:483:3: error: read-only location '*end' used
as 'asm' output
Now in -next:
http://kisskb.ellerman.id.au/kisskb/buildresult/6100650/
http://kisskb.ellerman.id.au/kisskb/buildresult/6100673/
http://kisskb.ellerman.id.au/kisskb/buildresult/6100860/
Gr{oetje,eeting}s,
? ? ? ? ? ? ? ? ? ? ? ? Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert at
linux-m68k.org
In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
? ? ? ? ? ? ? ? ? ? ? ? ? ?? ?? -- Linus Torvalds
