This patch adds support for the IB "base memory management extension"
(BMME) and the equivalent iWARP operations (which the iWARP verbs
mandates all devices must implement).  The new operations are:

 - Allocate an ib_mr for use in fast register work requests.

 - Allocate/free a physical buffer lists for use in fast register work
   requests.  This allows device drivers to allocate this memory as
   needed for use in posting send requests (eg via dma_alloc_coherent).

 - New send queue work requests:
   * send with remote invalidate
   * fast register memory region
   * local invalidate memory region
   * RDMA read with invalidate local memory region (iWARP only)

Consumer interface details:

 - A new device capability flag IB_DEVICE_MEM_MGT_EXTENSIONS is added
   to indicate device support for these features.

 - New send work request opcodes IB_WR_FAST_REG_MR, IB_WR_LOCAL_INV,
   IB_WR_RDMA_READ_WITH_INV are added.

 - A new consumer API function, ib_alloc_mr() is added to allocate
   fast register memory regions.

 - New consumer API functions, ib_alloc_fast_reg_page_list() and
   ib_free_fast_reg_page_list() are added to allocate and free
   device-specific memory for fast registration page lists.

 - A new consumer API function, ib_update_fast_reg_key(), is added to
   allow the key portion of the R_Key and L_Key of a fast registration
   MR to be updated.  Consumers call this if desired before posting
   a IB_WR_FAST_REG_MR work request.

Consumers can use this as follows:

 - MR is allocated with ib_alloc_mr().

 - Page list memory is allocated with ib_alloc_fast_reg_page_list().

 - MR R_Key/L_Key "key" field is updated with ib_update_fast_reg_key().

 - MR made VALID and bound to a specific page list via
   ib_post_send(IB_WR_FAST_REG_MR)

 - MR made INVALID via ib_post_send(IB_WR_LOCAL_INV),
   ib_post_send(IB_WR_RDMA_READ_WITH_INV) or an incoming send with
   invalidate operation.

 - MR is deallocated with ib_dereg_mr()

 - page lists dealloced via ib_free_fast_reg_page_list().

Applications can allocate a fast register MR once, and then can
repeatedly bind the MR to different physical block lists (PBLs) via
posting work requests to a send queue (SQ).  For each outstanding
MR-to-PBL binding in the SQ pipe, a fast_reg_page_list needs to be
allocated (the fast_reg_page_list is owned by the low-level driver
from the consumer posting a work request until the request completes).
Thus pipelining can be achieved while still allowing device-specific
page_list processing.

The 32-bit fast register memory key/STag is composed of a 24-bit index
and an 8-bit key.  The application can change the key each time it
fast registers thus allowing more control over the peer's use of the
key/STag (ie it can effectively be changed each time the rkey is
rebound to a page list).

Signed-off-by: Steve Wise <swise@opengridcomputing.com>
Signed-off-by: Roland Dreier <rolandd@cisco.com>