The data transfer and CDC message headers differ in SMC-R and SMC-D.
This patch adds support for the SMC-D data transfer to the existing SMC
code. It consists of the following:

* SMC-D CDC support
* SMC-D tx support
* SMC-D rx support

The CDC header is stored at the beginning of the receive buffer. Thus, a
rx_offset variable is added for the CDC header offset within the buffer
(0 for SMC-R).
Signed-off-by: NHans Wippel <hwippel@linux.ibm.com>
Signed-off-by: NUrsula Braun <ubraun@linux.ibm.com>
Suggested-by: NThomas Richter <tmricht@linux.ibm.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

SMC-D relies on PNETIDs to find usable SMC-D/ISM devices for a SMC
connection. This patch adds SMC-D/ISM support to the current PNETID
implementation.
Signed-off-by: NHans Wippel <hwippel@linux.ibm.com>
Signed-off-by: NUrsula Braun <ubraun@linux.ibm.com>
Suggested-by: NThomas Richter <tmricht@linux.ibm.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

SMC supports two variants: SMC-R and SMC-D. For data transport, SMC-R
uses RDMA devices, SMC-D uses so-called Internal Shared Memory (ISM)
devices. An ISM device only allows shared memory communication between
SMC instances on the same machine. For example, this allows virtual
machines on the same host to communicate via SMC without RDMA devices.

This patch adds the base infrastructure for SMC-D and ISM devices to
the existing SMC code. It contains the following:

* ISM driver interface:
  This interface allows an ISM driver to register ISM devices in SMC. In
  the process, the driver provides a set of device ops for each device.
  SMC uses these ops to execute SMC specific operations on or transfer
  data over the device.

* Core SMC-D link group, connection, and buffer support:
  Link groups, SMC connections and SMC buffers (in smc_core) are
  extended to support SMC-D.

* SMC type checks:
  Some type checks are added to prevent using SMC-R specific code for
  SMC-D and vice versa.

To actually use SMC-D, additional changes to pnetid, CLC, CDC, etc. are
required. These are added in follow-up patches.
Signed-off-by: NHans Wippel <hwippel@linux.ibm.com>
Signed-off-by: NUrsula Braun <ubraun@linux.ibm.com>
Suggested-by: NThomas Richter <tmricht@linux.ibm.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>