Re: [PATCH] 2.5 ide 48-bit usage

Linus Torvalds
2003-05-07T16:16:16Z

On Wed, 7 May 2003, Jens Axboe wrote:
>
> I did a patch for 2.4 some weeks ago that added (what I consider) proper
> 48-bit lba usage to ide-disk.

Ok, let me disagree a bit.

At least if I read the patch correctly, theer's no way for upper layers to
say "I want 48-bit addressing" - it's just turned on automatically for
high sectors (or big transfers).

Well, you can mark the drive itself as wanting 48-bit transfers, but you
can't do it on a per-request basis.

And I think this is 100% equivalent to the 6 vs 10 vs 16-byte SCSI command
issue, and I really think it should b esolved the same way. Namely, you
should be able to (on a "struct request" level) explicitly say that you
want the big requests, and then the default prep_fn() would do roughly
what you do now by default.

That way something like a SG_IO interface could force one mode or the
other on a per-request basis.

Comments?

Linus