Re: [RFC PATCH 2/2] ata: acpi: rework the ata acpi bind support

[Tejun Heo <tj@kernel.org>]

On Thu, Jul 25, 2013 at 01:47:03PM +0800, Aaron Lu wrote:
> Binding ACPI handle to SCSI device has several drawbacks, namely:
> 1 During ATA device initialization time, ACPI handle will be needed
>   while SCSI devices are not created yet. So each time ACPI handle is
>   needed, instead of retrieving the handle by ACPI_HANDLE macro,
>   a namespace scan is performed to find the handle for the corresponding
>   ATA device. This is inefficient, and also expose a restriction on
>   calling path not holding any lock.
> 2 The binding to SCSI device tree makes code complex, while at the same
>   time doesn't bring us any benefit. All ACPI handlings are still done
>   in ATA module, not in SCSI.
> 
> Rework the ATA ACPI binding code to bind ACPI handle to ATA transport
> devices(ATA port and ATA device). The binding needs to be done only once,
> since the ATA transport devices do not go away with hotplug. And due to
> this, the flush_work call in hotplug handler for ATA bay is no longer
> needed.

I like it but am wondering why we weren't doing this before.  Was the
acpi support added before we made ata objects proper devices?

Thanks.

-- 
tejun