Re: [RFC PATCH 1/3] block: add a flag to identify PM request

From: Alan Stern
Date: Tue May 15 2012 - 14:30:05 EST


On Tue, 15 May 2012, Lin Ming wrote:

> > > IDE code still uses both types and they are used for system
> > > suspend/resume. See generic_ide_suspend and generic_ide_resume.
> >
> > drivers/ide is obsolete code though so we shouldn't be forcing its needs
> > on the future
>
> Do you mean we don't care about breaking ide code?

As far as I can tell, Alan means that you shouldn't hesitate to change
the IDE code in order to make things easier for more up-to-date
systems. But don't _break_ the IDE driver!

> struct request {
> ....
> unsigned int cmd_flags;
> enum rq_cmd_type_bits cmd_type;
>
> Another reason I didn't reuse REQ_TYPE_PM_SUSPEND/REQ_TYPE_PM_RESUME is
> because all scsi requests set the cmd_type to REQ_TYPE_BLOCK_PC.
>
> So I think we should add a new cmd_flags(REQ_PM) to tell if it's a
> runtime pm request.

Yes, that does make more sense, even though it seems silly to have both
a flag and a type code for the same thing. Maybe the IDE driver could
be changed to use the new flag.

Alan Stern

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