On Mon, Jul 18, 2016 at 09:03:31AM -0600, Jeffrey Hugo wrote:
> On 7/18/2016 5:00 AM, Mark Rutland wrote:
> >Hi,
> >
> >On Sun, Jul 17, 2016 at 02:45:59PM -0600, Jeffrey Hugo wrote:
> >>+ if (status == EFI_BUFFER_TOO_SMALL ||
> >>+ (*buff_size - *map_size) / sizeof(*m) < 8) {
> >> efi_call_early(free_pool, m);
> >>+ /*
> >>+ * Make sure there is 8 entries worth of headroom so that the
> >>+ * buffer can be reused for a new map after allocations are
> >>+ * no longer permitted. Its unlikely that the map will grow to
> >>+ * exceed this headroom once we are ready to trigger
> >>+ * ExitBootServices()
> >>+ */
> >>+ *map_size += sizeof(*m) * 8;
> >As a general note, it's a shame that we don't know desc_size first time
> >through. If descs grow, 8 * sizeof(*m) might be too small. That's an
> >existing problem though, so I guess it makes sense to be consistent and
> >use sizeof(*m) here.
>
> Yep. Unless I've missed something, it seems like the two options
> are either make a decent attempt to guess at desc_size the first
> time (current approach), or intentionally fail the first time just
> to get the size. The current approach doesn't seem perfect, but it
> does have a chance at passing with just one attempt. I couldn't see
> a better solution, but if someone else has an idea, I'd like to hear
> it.
Sure, that was more of an observation than a critique. In the absence of
any suggestions better, sticking with sizeof(*m) makes sense.
If it does become a problem, we're likely to have to fix up other sites
regardless.
Thanks,
Mark.
--
To unsubscribe from this list: send the line "unsubscribe linux-efi" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
