Re: [Qemu-devel] [PATCH 03/15] scsi: move request lists to QTAILQ.

[Gerd Hoffmann]

On 11/17/09 12:59, Paul Brook wrote:
> On Tuesday 17 November 2009, Gerd Hoffmann wrote:
> > Changes:
> >   * Move from open-coded lists to QTAILQ macros.
> >   * Move the struct elements to the common data structures
> >     (SCSIDevice + SCSIRequest).
> >   * Fix request cleanup in the destroy callback.
>
> This feels like the abstraction boundaries wrong. If the request chain fields
> are in common structures then I'd also expect the allocation and linking code
> to be common.

Isn't that easy because scsi-disk and scsi-generic keep a pool of unused 
request structures.  I didn't change that for now, although I've 
considered dropping it.  Not sure how important it is these days, malloc 
implementations don't do slow+stupid list walks any more ...

When the pools are gone we can easily move scsi_remove_request() to 
common code and have the common scsi_req_init() function handle 
allocation and linking too (and probably name it 'alloc' or 'get').

cheers,
  Gerd