Re: [patch] My AMD IDE driver, v2.7

[Jeff Garzik]

Linus Torvalds wrote:

>On Mon, 11 Mar 2002, Linus Torvalds wrote:
>
>> - attach to one or more request queue(s). Notice that you should not have
>>   _one_ module that handles all request queues, because the filter module
>>   obviously has to be different for an ATA disk than for a SCSI disk, and
>>   in fact it might be different for an IBM ATA disk than for a Maxtor ATA
>>   disk, for example.
>>
>
>Btw, to tie this back to the other IDE thread, namely the suspend/resume 
>thing, I think things like that should also just push commands down the 
>request list. In particular, instead of waiting until the handler is NULL, 
>it should do something like
>
> - create a "sync" request
> - do the equivalent of
>
>	DECLARE_COMPLETION(wait);
>	rq->waiting = &wait;
>	q->elevator.elevator_add_req_fn(q, rq, queue_head);
>	wait_for_completion(&wait);
>
>which automatically synchronizes with any outstanding requests (simply 
>by virtue of the elevator knowing not to re-order/merge special requests, 
>so when the sync command in finished, we know all other commands have 
>finished too).
>

Dumb question, why create a separate request?

Why not just have some way to wait for request X (and flag it for 
no-merge/barrier treatment, etc.)?  bios have end_io callbacks...

    Jeff