Re: Request for comments (kdev_t and friends...)

Linus Torvalds (torvalds@transmeta.com)
Fri, 26 Nov 1999 11:02:06 -0800 (PST)


On Fri, 26 Nov 1999 Andries.Brouwer@cwi.nl wrote:
>
> But how is that different from the planned kdev_t?
>
> Your "struct block_device *" is precisely kdev_t.

No.

Notice that "kdev_t" implies that all devices have the same kind of
pointer.

"struct block_device" implies that, for example, character devices are of
a completely different type.

Also, the difference is in reference counting. The current setup assumes
that you never have to "put" a reference to kdev_t, which is just broken
in a dynamic environment - we do NOT want to be required to hold on to
"struct block_device" data structures forever, we need to also clean them
up after they are no longer referenced by anybody.

It's more of an evolution of kdev_t, and I agree with you 100% in that
sense.

Linus

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