Re: [PATCH] scsi sysfs cleanups

[Christoph Hellwig <hch@infradead.org>]

On Tue, Nov 19, 2002 at 10:39:08AM -0800, Mike Anderson wrote:
> I was trying to ensure consistency and type checking of class_data used
> by host of class type scsi-host.
> 
> In the device model the struct device contains three void pointers for
> use by associated member. driver_data is a private data pointer for the
> device driver. class_data is for use by the class in this case scsi-host
> class.

Still the casts make no sense at all.  in C you can assign a void pointer
to any other pointer and the other way around.

> 
> The *device_driver* interfaces are possibly not needed any more as I
> originally had them exported because they where being called directly by
> the upper layers.  Now they are being called by the mid-layer which this
> *.o is linked. In the future the upper layers could call these directly
> as the operations in scsi_register_device are handled by the sysfs layer
> if upper layers fully support the device model probe / remove / release.

But they shouldn't.  Each additional exported interface makes life harder.
Please don't export stuff unless it's really required.

> The *host_class* are interfaces for the LLDD to call to register and
> unregister as a scsi host class driver.
> 
> These interfaces are used in a scsi_debug patch I have beyond scsi_debug
> 1.65 that demonstrate the used of these interfaces.

Again, see above.  What do these interfaces actually gain us over
scsi_add_host/scsi_remove_host?  If it helps us in practice (of which I
still need to be convienced) remove scsi_add_host/scsi_remove_host when
exporting those, but don't keep both.