Re: [PATCH 6/6] blk-mq: remove REQ_ATOM_STARTED

[Tejun Heo]

Hello,

On Wed, Dec 13, 2017 at 11:05:11AM +0800, jianchao.wang wrote:
> Just don't quite understand the strict definition of "generation" you said.
> A allocation->free cycle is a generation ? or a idle->in-flight cycle is a
> generation? The idle->in-flight cycle could include the requeue case as above.
> Can you clarify this?

So, a request is

* IN_FLIGHT, if it can be completed by the lower level driver

* COMPLETE, if the lower level driver indicated completion but block
  layer is still processing.

* IDLE, if neither of the above two.

and generation is bumped up on IDLE -> IN_FLIGHT to distinguish
different IN_FLIGHT instances.

Thanks.

-- 
tejun