Re: RDMA Read: Local protection error

[Sagi Grimberg <sagi-NQWnxTmZq1alnMjI0IkVqw@public.gmane.org>]

>> But this is specific to mlx4 which supports up 511 pages per MR, mlx5
>> will need a coherent allocation anyways right (it supports up to 64K
>> pages per MR)?
>
> Why does that make a difference?

Chuck's original bug report said that the problem with the current
code is that dma_map_single expects the pages array to fit in a single
page:

"
See what mlx4_alloc_priv_pages does with this memory
allocation:

   mr->page_map = dma_map_single(device->dma_device, mr->pages,
                                 size, DMA_TO_DEVICE);

dma_map_single() expects the mr->pages allocation to fit
on a single page, as far as I can tell.
"

But when I revisited dma_map_single in some archs I didn't
see this expectation. So actually now I don't really see what
is the problem in the first place (or how your patch fixes it)...
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