From: Jiri Pirko <redacted>

RDMA device names are unique system-wide today:
__ib_device_get_by_name() checks a requested name against every
registered device regardless of the network namespace it lives in.
A device in one network namespace therefore cannot use a name already
taken in another, even in exclusive netns mode (netns_mode=0) where
the two are otherwise isolated. Net devices have no such restriction -
their names only need to be unique within a network namespace.

This series makes RDMA device names unique per network namespace,
matching net device semantics, and adapts the users that assumed
system-wide unique names.

Scoping reuses the existing rdma_dev_access_netns() predicate, so
behavior only changes in exclusive mode:
  - shared mode (default): names stay unique system-wide, no change;
  - exclusive mode: names only need to be unique within a namespace;
  - CONFIG_NET_NS=n: everything is init_net, names stay system-wide
    unique.

There are two users that cannot be made per-namespace and are
documented as known limitations instead of changed:
  - the rdma_cm configfs tree: configfs has no network namespace
    support, so it cannot represent two same-named devices;
  - SELinux ibendport labelling: endports are labelled by (device
    name, port) from a global policy; distinguishing same-named
    devices would need net namespace support in the SELinux policy
    language and tooling.

Tested with the new rxe_netns_names kselftest added in the last patch.

Jiri Pirko (13):
  RDMA/core: Pass the net namespace to the device name lookups
  RDMA/core: Handle device name conflicts when changing net namespace
  RDMA/core: Support renaming a device when changing its net namespace
  RDMA/nldev: Report net namespace move errors through extack
  RDMA/nldev: Allow setting the device name while changing net namespace
  net/smc: Look up the pnetid ib device within the net namespace
  RDMA/srp: Make the SRP sysfs class net namespace aware
  RDMA/cgroup: Scope rdma cgroup device visibility to the net namespace
  RDMA/cma: Document that CM configfs cannot be net namespace scoped
  RDMA/core: Document the SELinux ibendport net namespace limitation
  RDMA/core: Make device names unique per net namespace
  RDMA/rxe: Implement disassociate_ucontext callback
  RDMA/selftests: Add rxe_netns_names test

 Documentation/ABI/testing/configfs-rdma_cm    |   4 +
 Documentation/admin-guide/cgroup-v2.rst       |   7 +
 drivers/infiniband/core/cgroup.c              |  12 +
 drivers/infiniband/core/cma_configfs.c        |   4 +
 drivers/infiniband/core/core_priv.h           |  15 +-
 drivers/infiniband/core/device.c              | 256 +++++++++++++---
 drivers/infiniband/core/nldev.c               |  26 +-
 drivers/infiniband/core/security.c            |   6 +
 drivers/infiniband/sw/rxe/rxe_verbs.c         |   5 +
 drivers/infiniband/ulp/srp/ib_srp.c           |  16 +-
 include/linux/cgroup_rdma.h                   |  10 +
 include/uapi/rdma/rdma_netlink.h              |   5 +-
 kernel/cgroup/rdma.c                          |  20 +-
 net/smc/smc_pnet.c                            |  20 +-
 tools/testing/selftests/rdma/Makefile         |   3 +-
 tools/testing/selftests/rdma/config           |   2 +
 .../testing/selftests/rdma/rxe_netns_names.sh | 282 ++++++++++++++++++
 17 files changed, 639 insertions(+), 54 deletions(-)
 create mode 100755 tools/testing/selftests/rdma/rxe_netns_names.sh

-- 
2.54.0