Re: [PATCH] ide: limit drive capacity to 137GB if host doesn't support LBA48

[Andries Brouwer]

On Thu, Aug 14, 2003 at 09:53:28AM +0100, Alan Cox wrote:
> On Iau, 2003-08-14 at 02:24, Bartlomiej Zolnierkiewicz wrote:
> >  	hwif->rqsize			= old_hwif.rqsize;
> > -	hwif->addressing		= old_hwif.addressing;
> > +	hwif->no_lba48			= old_hwif.no_lba48;
> 
> This change is a bad idea. Its called "addressing" because that is what
> it is about (see SATA and ATA specs). In future SATA addressing becomes
> a 0,1,2 value because 48bits isnt enough, it may get more forms beyond
> that.
> 
> Might be worth defining ADDR_LBA48, ADDR_LBA28 etc to make it clearer,
> but really people shouldnt be randomly hacking IDE code without having
> read the specifications.

Bartlomiej chose "no_lba48" (I had "cannot_do_lba48"), but otherwise
the change is mine. I will contradict you that it is a bad idea -
indeed, it is an excellent idea.
(Indeed, I made the change just for making the code more readable,
but immediately afterwards, reading this more readable code,
I understood why people had been experiencing filesystem corruption.)

Your strange remarks about reading specs - no doubt everybody who
touches IDE code knows the specs.

I don't know whether you saw my first post - but just to be sure let
me repeat a bit. There are two things that both are called addressing.
One is drive->addressing, and it is the enum that it looks like you
are thinking of. The other is hwif->addressing, and it is a boolean.
If this is ever changed then we have to visit all occurrences, and
also that is easier with the new name.

Andries

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