[PATCH V3 0/2] Function for improved node descriptions

[Michael Heinz <michael.heinz-h88ZbnxC6KDQT0dZR+AlfA@public.gmane.org>]

Changes from Version 2:

Changed the function to skip over '%' fields that aren't supported and added
code to ensure the string is null terminated no matter how it was formatted.

Changed the default description to more closely match the current OFED behavior.
The new default is '%h HCA-%d'. For example:

homer HCA-mthca0
node-a2 HCA-qib1
lisa HCA-mlx4_0

Changes from Version 1:

Replaced the original substitution of the hostname for '@' with an 
implementation of the '%h' and '%d' fields.

Description:

The common practice in IB fabrics is to set the description of an HCA to be
the hostname of the machine plus a description (i.e., "myhost hca-1",
"myhost hca-2", etc..)

This has a limitation, however.  The first is that if the machine's hostname
is set via DHCP, the HCA description may be set before the hostname is, leading
to an incorrect description. This can also occur if the machine's hostname
changes for some other reason after boot.

This can cause difficulties and confusion when trying to maintain a large
fabric - if all your nodes are described as "localhost HCA-1" it can be very
difficult to figure out which node is suffering from symbol errors.

This patch addresses the problem by providing a function to build the node
description. If the provided source string for the description contains a '%h'
it will be replaced at read time with the hostname of the node. If the provided
source string contains a '%d' it will be replaced at read time with the name of
the HCA.  For example, if the node description of the second HCA on node-a13 is
set to'%h: %d', at read time this will be expanded to read "node-a2: qib1".

This ensures that even after a fabric has been completely initialized, if a
node's hostname changes, that change will be reflected in the next "heavy"
sweep of the SM, but also maintains compatibility with existing code since the
behavior is unchanged if the description string does not contain a '%'
character.

---

Michael Heinz (2):
      Function for improved node descriptions
      Add support for ib_build_node_desc() to the HCAs.


 drivers/infiniband/core/mad.c                |   39 ++++++++++++++++++++++++++
 drivers/infiniband/hw/ipath/ipath_mad.c      |    2 +
 drivers/infiniband/hw/ipath/ipath_verbs.c    |    3 +-
 drivers/infiniband/hw/mlx4/mad.c             |    2 +
 drivers/infiniband/hw/mlx4/main.c            |    2 +
 drivers/infiniband/hw/mthca/mthca_mad.c      |    2 +
 drivers/infiniband/hw/mthca/mthca_provider.c |    2 +
 drivers/infiniband/hw/qib/qib_mad.c          |    2 +
 drivers/infiniband/hw/qib/qib_verbs.c        |    3 +-
 include/rdma/ib_mad.h                        |    9 ++++++
 include/rdma/ib_verbs.h                      |    3 +-
 11 files changed, 58 insertions(+), 11 deletions(-)

-- 
Signed-off-by: Michael Heinz <michael.heinz-h88ZbnxC6KDQT0dZR+AlfA@public.gmane.org>
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