Re: [PATCH 2.6.30] xprtrdma: The frmr iova_start values are truncated by the nfs rdma client.

[Steve Wise <swise@opengridcomputing.com>]

Tom Talpey wrote:
> At 02:57 PM 4/26/2009, Steve Wise wrote:
>   
>> Hey Trond,
>>
>> Turns out the server side is fine.  So this patch is good to go.
>>     
>
> I'll ACK the patch, but I do wonder if the code will compile cleanly on all
> platforms. The iova_start is a u64, whereas the mr_dma is a dma_addr_t,
> which is variable sized, depending on platform. Would a (u64) cast be a
> safer patch, warning-wise?
>
>   

Well, if dma_addr_t is smaller, I don't think you'll get a warning, will 
you?  And if its larger than 64b, then you _want_ the warning, because 
nothing will work. :)

Its up to you and/or Trond.

Steve.


> Tom.
>
>   
>> Thanks,
>>
>> Steve.
>>
>> Steve Wise wrote:
>>     
>>> Trond,
>>>
>>> There is a similar bug in the server side too.  I'll repost a single 
>>> patch that fixes both.
>>>
>>> Steve.
>>>
>>> Steve Wise wrote:
>>>       
>>>> A bad cast causes the iova_start, which in this case is a DMA bus 
>>>> address,
>>>> to be truncated on 32b systems.  No cast is needed.
>>>>
>>>> Signed-off-by: Steve Wise <swise@opengridcomputing.com>
>>>> ---
>>>>
>>>>  net/sunrpc/xprtrdma/verbs.c |    2 +-
>>>>  1 files changed, 1 insertions(+), 1 deletions(-)
>>>>
>>>> diff --git a/net/sunrpc/xprtrdma/verbs.c b/net/sunrpc/xprtrdma/verbs.c
>>>> index 3b21e0c..3a374f5 100644
>>>> --- a/net/sunrpc/xprtrdma/verbs.c
>>>> +++ b/net/sunrpc/xprtrdma/verbs.c
>>>> @@ -1489,7 +1489,7 @@ rpcrdma_register_frmr_external(struct 
>>>> rpcrdma_mr_seg *seg,
>>>>      memset(&frmr_wr, 0, sizeof frmr_wr);
>>>>      frmr_wr.opcode = IB_WR_FAST_REG_MR;
>>>>      frmr_wr.send_flags = 0;            /* unsignaled */
>>>> -    frmr_wr.wr.fast_reg.iova_start = (unsigned long)seg1->mr_dma;
>>>> +    frmr_wr.wr.fast_reg.iova_start = seg1->mr_dma;
>>>>      frmr_wr.wr.fast_reg.page_list = 
>>>> seg1->mr_chunk.rl_mw->r.frmr.fr_pgl;
>>>>      frmr_wr.wr.fast_reg.page_list_len = i;
>>>>      frmr_wr.wr.fast_reg.page_shift = PAGE_SHIFT;
>>>>
>>>> -- 
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>>>>   
>>>>         
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>>>       
>>