Re: [PATCH 1/4] scsi: Allow hosts to be flagged as hotpluggable

Stefan Richter
2009-07-16T14:30:13Z

Matthew Garrett wrote:
> Userspace may wish to make policy decisions based on whether a host
> supports device hotplug or not - for example, AHCI link power management
> disables hotplug, so may only be desirable on hotplug ports. Add
> support for marking hosts as hotpluggable in order to allow userspace to
> treat them appropriately.
[...]
> --- a/include/scsi/scsi_host.h
> +++ b/include/scsi/scsi_host.h
> @@ -421,6 +421,7 @@ struct scsi_host_template {
> */
> unsigned unchecked_isa_dma:1;
>
> +
> /*
> * True if this host adapter can make good use of clustering.
> * I originally thought that if the tablesize was large that it
> @@ -447,6 +448,11 @@ struct scsi_host_template {
> unsigned ordered_tag:1;
>
> /*
> + * True if host supports hotplugging
> + */
> + unsigned hotpluggable:1;
> +

The comment should specify what the actual effects of the flag are.

(Provides the default for Scsi_Host.hotpluggable?)

> + /*
> * Countdown for host blocking with no commands outstanding.
> */
> unsigned int max_host_blocked;
> @@ -622,6 +628,9 @@ struct Scsi_Host {
> /* Asynchronous scan in progress */
> unsigned async_scan:1;
>
> + /* 1 if hotpluggable, 0 if not */
> + unsigned hotpluggable:1;
> +

Ditto here.

(Is used by power management infrastructure to decide over runtime PM
policy? I.e. don't enter power states which would prevent the port from
detecting/ reporting hotplug events?)

> /*
> * Optional work queue to be utilized by the transport
> */

--
Stefan Richter
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