Re: [RFC] current libata eh doc

[Jeff Garzik <jgarzik@pobox.com>]

Tejun Heo wrote:
> Jeff Garzik wrote:
>> I would note that ->complete_fn() is the asynchronous path, and 
>> qc->waiting is the synchronous (sleeping in process context) path.

>  Okay.  One question though.  Is it necessary to keep these two 
> separate?  qc->waiting can easily be implemented in terms of 
> ->complete_fn() if we add a void *udata argument to it.  Is there any 
> design consideration I'm not aware of?


Synchronous usage (use of qc->waiting) is common and growing more 
common, so it seemed expedient to put 'waiting' in the data structure. 
I also thought it might be nice to have the completion occur after the 
->complete_fn() callback and tag poisoning occurred.

Certainly qc->waiting can be implemented in terms of ->complete_fn(). 
But unless unseen elegance (or bug fixes) will result, I'm not terribly 
inclined to change it.

	Jeff