[ofa-general] [PATCH][REPOST] drivers/infiniband/ulp/srpt: Fixtarget data corruption

[Vu Pham]

Vladislav Bolkhovitin wrote:
> Vu Pham wrote:
>> Vladislav Bolkhovitin wrote:
>>
>>> Robert Pearson wrote:
>>>
>>>> Vlad,
>>>>
>>>> I think we agree. But, when we tried the experiment of running 
>>>> without the
>>>> local memory allocator scst hung when we did large IO operations. 
>>>> Probably
>>>> something simple.
>>>
>>> Why do you think it scst hung, not something else? Do you have 
>>> evidences for that? ;) According to Vu, you can't simply switch to 
>>> SCST memory allocator, because IB hardware has very limited number of 
>>> available SG entries in commands (few tens), so for large request, 
>>> where there are too many SG entries, they should be "iomapped" using 
>>> the corresponding IB facility.
>>
>> No - you can easily switch to SCST memory by set srpt's module 
>> parameter mem_element=0. There is limited number of sg entries per IB 
>> work request (29); however, the current srpt can submit several IB 
>> work requests to cover large sg entries IO.
> 
> What's the point in the internal memory management in the SRPT driver then?
> 

+ To avoid some back-end storage which can not handle big sg 
entries
+ To save work requests

However, I agree that I need to remove srpt' internal memory 
management.

-vu