RDMA/core: Introduce peer memory interface

The peer_memory_client scheme allows a driver to register with the ib_umem
system that it has the ability to understand user virtual address ranges
that are not compatible with get_user_pages(). For instance VMAs created
with io_remap_pfn_range(), or other driver special VMA.

For ranges the interface understands it can provide a DMA mapped sg_table
for use by the ib_umem, allowing user virtual ranges that cannot be
supported by get_user_pages() to be used as umems for RDMA.

This is designed to preserve the kABI, no functions or structures are
changed, only new symbols are added:


And a bitfield in struct ib_umem uses more bits.

This interface is compatible with the two out of tree GPU drivers:

Signed-off-by: Yishai Hadas <yishaih@mellanox.com>
Signed-off-by: Feras Daoud <ferasda@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
Signed-off-by: Leon Romanovsky <leonro@nvidia.com>
12 files changed