linux_dsm_epyc7002/drivers/infiniband/ulp/ipoib
Pradeep Satyanarayana 68e995a295 IPoIB/cm: Add connected mode support for devices without SRQs
Some IB adapters (notably IBM's eHCA) do not implement SRQs (shared
receive queues).  The current IPoIB connected mode support only works
on devices that support SRQs.

Fix this by adding support for using the receive queue of each
connected mode receive QP.  The disadvantage of this compared to using
an SRQ is that it means a full queue of receives must be posted for
each remote connected mode peer, which means that total memory usage
is potentially much higher than when using SRQs.  To manage this, add
a new module parameter "max_nonsrq_conn_qp" that limits the number of
connections allowed per interface.

The rest of the changes are fairly straightforward: we use a table of
struct ipoib_cm_rx to hold all the active connections, and put the
table index of the connection in the high bits of receive WR IDs.
This is needed because we cannot rely on the struct ib_wc.qp field for
non-SRQ receive completions.  Most of the rest of the changes just
test whether or not an SRQ is available, and post receives or find
received packets in the right place depending on the answer.

Cleaning up dead connections actually becomes simpler, because we do
not have to do the "last WQE reached" dance that is required to
destroy QPs attached to an SRQ.  We just move the QP to the error
state and wait for all pending receives to be flushed.

Signed-off-by: Pradeep Satyanarayana <pradeeps@linux.vnet.ibm.com>

[ Completely rewritten and split up, based on Pradeep's work.  Several
  bugs fixed and no doubt several bugs introduced.  - Roland ]

Signed-off-by: Roland Dreier <rolandd@cisco.com>
2008-01-25 14:15:24 -08:00
..
ipoib_cm.c IPoIB/cm: Add connected mode support for devices without SRQs 2008-01-25 14:15:24 -08:00
ipoib_fs.c [PATCH] mark struct file_operations const 3 2007-02-12 09:48:45 -08:00
ipoib_ib.c IPoIB: Trivial formatting cleanups 2008-01-25 14:15:23 -08:00
ipoib_main.c IPoIB/cm: Add connected mode support for devices without SRQs 2008-01-25 14:15:24 -08:00
ipoib_multicast.c IPoIB: Trivial formatting cleanups 2008-01-25 14:15:23 -08:00
ipoib_verbs.c IPoIB/cm: Add connected mode support for devices without SRQs 2008-01-25 14:15:24 -08:00
ipoib_vlan.c IPoIB: Allow setting policy to ignore multicast groups 2007-10-10 13:02:30 -07:00
ipoib.h IPoIB/cm: Add connected mode support for devices without SRQs 2008-01-25 14:15:24 -08:00
Kconfig IB: Use menuconfig for InfiniBand menu 2007-07-09 20:12:26 -07:00
Makefile IPoIB: Connected mode experimental support 2007-02-10 08:00:48 -08:00