Re: [PATCH 06/13] async_tx: add support for asynchronous GF multiplication

From: Ilya Yanok
Date: Fri Mar 20 2009 - 19:01:23 EST


Hi H. Peter,

H. Peter Anvin wrote:
>> Something is broken if we take this path. This routine could stand to
>> have a WARN_ONCE(), because if it is ever called there is something is
>> wrong with the raid6 offload driver. The intent is that the
>> asynchronous recovery routines will perform an early check to see if
>> the recovery can be offloaded (with a series of calls to
>> async_xor/async_pq). If not we fall back to the optimized synchronous
>> recovery routines (raid6_2data_recov, raid6_datap_recov). The only
>> time this path will be taken is if we have decided to perform
>> asynchronous recovery but at a later call to async_pq the offload
>> driver reports it has run out of descriptors.
>>
>
> That doesn't explain what you expect the code to do. It still doesn't
> make sense to me.

We defined async_pq() function as hardware can do GF multiplication of
arbitrary elements and we want to take advantage of this fact. But by
the design of ASYNC_TX API we have to provide synchronous version of
that function too.

Regards, Ilya.

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