Re: [Evms-devel] Re: Linux v2.5.42

Christoph Hellwig
2002-10-14T15:15:46Z

On Mon, Oct 14, 2002 at 01:41:51AM +0800, Michael Clark wrote:
> From the discussion so far:
>
> Pros
> * Simplify ioctl routing to plugins

* allow code reuse
* simplify userspace access to intermediate layer
* avoid data duplication
* avoid having different data structures for very differen things

> Cons
> * Chew up a minor
> * Get a block device we don't need or want (ie. we can still easily
> directly access the underlying physical block devices)
> * loose purely logical remapping abstraction in plugins

Explain the exact meaning of this to non/native speakers like me, please

> * Complicate mapping of request queues to devices (ie. shouldn't only
> the top level volume device and the underlying physical devices need
> request queues)

You need struct request queue as data structure, but you don't actually
need a queue. Please check the code.

And no, I don't think having a peoper, custom make_request_fn will
complicate the code.