Re: [PATCH v4 1/1] block: Add test-iosched scheduler

[merez@codeaurora.org]

On Tue, June 12, 2012 1:13 pm, Jeff Moyer wrote:
> merez@codeaurora.org writes:
>
>> On Tue, June 12, 2012 7:09 am, Jeff Moyer wrote:
>>> Maya Erez <merez@codeaurora.org> writes:
>>>
>>>> The test scheduler allows testing a block device by dispatching
>>>> specific requests according to the test case and declare PASS/FAIL
>>>> according to the requests completion error code
>>>
>>> What sort of tests have you written that make use of this
>>> infrastructure?
>>>
>>>> @@ -1072,8 +1072,6 @@ struct request *blk_get_request(struct
>>>> request_queue *q, int rw, gfp_t gfp_mask)
>>>>  {
>>>>  	struct request *rq;
>>>>
>>>> -	BUG_ON(rw != READ && rw != WRITE);
>>>> -
>>>
>>> Please explain this.
>> get_request and get_request_wait, called by blk_get_request, expects to
>> get the REQ_SYNC flag in addition to the read/write flag. Moreover, it
>> uses the REQ_SYNC flag in its algorithm decision making.
>> However blk_get_request expects to get a Boolean to indicate only
>> read/write flag and cannot handle the REQ_SYNC flag.
>
> Right, so why is it okay to change this?  Right now, blk_get_request is
> used for block special requests.  There is no sense of sync vs. async
> for such requests (that's an fs request notion).  Perhaps you're calling
> the wrong function?
>
> Cheers,
> Jeff
>
I use this function to get a WRITE_FLUSH request (which includes in its
flags the REQ_SYNC flag).
Is there another function I should use for this purpose?

Thanks,
Maya
-- 
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