On Sun, Oct 31, 2021 at 12:41 PM Jens Axboe <axboe@xxxxxxxxx> wrote:
>
> On top of the core block branch, this topic branch cleans up the bdev
> size handling.
So on the whole this seems to be a good cleanup, but some of it worries me.
For example, it seems to have lost the cast to "loff_t" when
generating the byte size from a "sector_t".
Ok, so these days those are both 64-bit, and it doesn't actually
matter (the time when we had a 32-bit sector_t as an option are long
gone), but I think that bdev_nr_bytes() helper really ends up being
subtler than it looks. It very much depends on 'sector_t' and 'loff_t'
being the same size (although sector_t is an u64, loff_t ends up being
the signed version).
I've pulled this, but I do think it might have been better with the
type conversion being explicit. One of the reasons we had "sector_t"
originally was that it ended up being configuration-dependent, and
could be 32-bit. Those times may be gone, but it's still conceptually
a very different type from "loff_t".
Linus
