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Date: Tue, 17 Nov 2009 13:39:38 +0100
From: Gerd Hoffmann <kraxel@redhat.com>
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Subject: Re: [Qemu-devel] [PATCH 03/15] scsi: move request lists to QTAILQ.
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To: Paul Brook <paul@codesourcery.com>
Cc: qemu-devel@nongnu.org

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