Re: end_request() deprecated, which one should be used ?

[Jens Axboe <jens.axboe@xxxxxxxxxx>]

On Mon, Sep 01 2008, Thomas Petazzoni wrote:
> Hi,
> 
> The comment at the top of end_request() says:
> 
>  *     This is a remnant of how older block drivers handled IO completions.
>  *     Modern drivers typically end IO on the full request in one go, unless
>  *     they have a residual value to account for. For that case this function
>  *     isn't really useful, unless the residual just happens to be the
>  *     full current segment. In other words, don't use this function in new
>  *     code. Either use end_request_completely(), or the
>  *     end_that_request_chunk() (along with end_that_request_last()) for
>  *     partial completions.
> 
> But unless I'm blind, neither end_request_completely() nor
> end_request_chunk() exist.
> 
> There are several request completion notification functions
> (end_request, end_queued_request, end_dequeued_request, blk_end_request
> and __blk_end_request). Which ones should be used in what case ?
> 
> If end_request() is deprecated, I suspect that the goal is to deprecate
> all end_*_request() functions as well, is it correct ? If so, is that
> correct that one should use blk_end_request() when the queue lock is
> not held, and __blk_end_request() if the queue lock is already held ?

end_request() is deprecated, and only that one. You can use
end_dequeued_request() or end_queued_request() to completely end a
dequeued or queued request. Or you can use blk_end_request() to end
nr_bytes of IO on that request. Those are the functions that you should
use. And yes, you should use __blk_end_request() if you already have the
queue lock grabbed.

-- 
Jens Axboe


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