[PATCH v3 12/20] RDMA/rw: use dma_map_sgtable()

[Jason Gunthorpe]

On Thu, Sep 16, 2021 at 05:40:52PM -0600, Logan Gunthorpe wrote:
> dma_map_sg() now supports the use of P2PDMA pages so pci_p2pdma_map_sg()
> is no longer necessary and may be dropped.
> 
> Switch to the dma_map_sgtable() interface which will allow for better
> error reporting if the P2PDMA pages are unsupported.
> 
> The change to sgtable also appears to fix a couple subtle error path
> bugs:
> 
>   - In rdma_rw_ctx_init(), dma_unmap would be called with an sg
>     that could have been incremented from the original call, as
>     well as an nents that was not the original number of nents
>     called when mapped.
>   - Similarly in rdma_rw_ctx_signature_init, both sg and prot_sg
>     were unmapped with the incorrect number of nents.

Those bugs should definately get fixed.. I might extract the sgtable
conversion into a stand alone patch to do it.

But as it is, this looks fine

Reviewed-by: Jason Gunthorpe <jgg at nvidia.com>

Jason