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

Steve Wise
2009-04-27T17:37:06Z

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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>>