Re: [PATCH 7/8] md: update_size(): Remove useless variable "fit".

[Neil Brown <neilb@xxxxxxx>]

On Wednesday July 9, maan@xxxxxxxxxxxxxxx wrote:
> > If you are keen to do some more tidying up, I would really love it if
> > all internal values that are currently stored as 'K' would instead be
> > stored as sectors.
> > So for example with update_size, we could make the value that is
> > passed in be a number of sectors, get rid of those divisions.
> 
> Of course the size unit exported to user space programs via sysfs must
> not change. So if we change update_size() as you propose, the division
> has to be done in the size_store() instead, which calls update_size()
> with a value obtained from sysfs.

Correct - the unit exported to userspace must not change.
We could conceivably make it fractional though.
    100.5
for 201 sectors.
size_store would do a multiplication:
       err = update_size(mddev, size*2);
size_show would do a division:
	return sprintf(page, "%llu\n", mddev->size/2);
or conceivably
	return sprintf(page, "%llu%s\n", mddev->size/2,
			(mddev->size&1) ? ".5":"");

> 
> Therefore I think it's impossible to completely get rid of the
> divisions/multiplications without breaking user space, but it might
> still be worth to change the internal representations.

Exactly how I see it.

> 
> I will have a look at it, but I might need some further advice.
> 
> > BTW your patches arrive without a valid "To" field.  The Date is odd
> > too.
> 
> They were generated by git-format-patch and then bounced to the
> list. The date is "correct" in the sense that I checked them in back
> then. I'll see that subsequent patches have a proper date and a valid
> "To" field.

The date wasn't a problem, it just seemed odd.  Your explanation makes
perfect sense.
I think you are "supposed" to use 
          git-send-mail --to linux-raid@xxxxxxxxxxxxxxx ...
to send the mail.  That sticks in a "To:".  Without the "To:" is have
to edit the headers to reply to the list (which isn't a big problem).

Thanks,
NeilBrown
--
To unsubscribe from this list: send the line "unsubscribe linux-raid" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html