Re: What to do about the 2TB limit on HDIO_GETGEO ?

From: Greg KH
Date: Tue Mar 25 2008 - 15:25:48 EST


On Tue, Mar 25, 2008 at 01:37:03PM -0400, Mark Lord wrote:
> H. Peter Anvin wrote:
>> Mark Lord wrote:
>>>
>>> Yeah, that would be just as good, really. Maybe even better.
>>>
>>> Mark Lord wrote (later on):
>>>> Instead, software has to search everything inside /sys/block/
>>>> looking for a "dev" file whose contents match,
>>>> rather than just trying to access something like this:
>>>>
>>>> /sys/block/8:1/start
>>>> or
>>>> /sys/block/majors/8/minors/1/start
>>>>
>>>> Or any one of a number of similar ways to arrange it.
>>> ..
>> It shouldn't be under /sys/block... there are enough many things that scan
>> /sys/block and assume any directory underneath it has the current format.
> ..
>
> So long as we only add things, and not remove them, then any software
> that scans /sys/block/ shouldn't care, really.
>
> But yes, it could go elsewhere, too.
> Perhaps a /sys/dev/ directory, populated with symbolic links
> (or hard links?) back to the /sys/block/ entries, something like this:
>
> /sys/dev/block/8:0 -> ../../../block/sda
> /sys/dev/block/8:1 -> ../../../block/sda/sda1
> /sys/dev/block/8:2 -> ../../../block/sda/sda2
> ...
>
> That's just a suggestion, really.
> And what about character devices?
>
> Perhaps Greg will chime in.

I've been waiting to see if sanity will take hold of anyone here.

Come on people, adding symlinks for device major:minor numbers in sysfs
to save a few 10s of lines of userspace code? Can things get sillier?

You can add a single udev rule to probably build these in a tree in /dev
if you really need such a thing...

And what's wrong with your new ioctl recomendation?

greg k-h
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