[ofa-general] [RFC] [PATCH 0/3] 2.6.23: basic support for IB routers

[Sean Hefty]

Re-sending - typo in mailing list name...

I'd like to get feedback about incorporating the following changes to support
IB routers into 2.6.23.  The goal of the patches is to allow for IB router
development and prototyping within the current framework of IBA.  The changes
themselves are fairly minimal, but based on the following concepts:

* Routing data is maintained by the local SA.  No assumption is made regarding
  how the SA obtains routing information.  The SA is only expected to respond
  to cross subnet PR queries by providing a path to the local router.  This
  matches the behavior in opensm.

* A ULP connecting to a remote subnet provides path information about both
  subnets.  For now the implementation simply assumes that the properties of
  the remote path match that of the local path.  This allows the active side
  CM to properly format the CM REQ.

* If the SLID/DLID values in the CM REQ are set to the permissive LID, then
  the passive side CM uses the SLID/DLID/SL values from the received CM REQ
  LRH to configure the passive side QP.  This is done to meet C9-54 without
  requiring communication with the remote SA, but I should note that this
  behavior is non-compliant.

These changes were tested by establishing a connection and transferring data
between two IB subnets connected by an Obsidian router.

These patches are also available in the ib_router branch of my rdma-dev.git
tree.  The tree is based on 2.6.21, so include a couple of additional patches
that were already pushed for 2.6.22.

Signed-off-by: Sean Hefty <sean.hefty at intel.com>