linux-stable/drivers/infiniband/ulp/ipoib
Christoph Lameter 633d610212 RDMA/ipoib: Remove racy Subnet Manager sendonly join checks
When a system receives a REREG event from the SM, then the SM information
in the kernel is marked as invalid and a request is sent to the SM to
update the information. The SM information is invalid in that time period.

However, receiving a REREG also occurs simultaneously in user space
applications that are now trying to rejoin the multicast groups. Some of
those may be sendonly multicast groups which are then failing.

If the SM information is invalid then ib_sa_sendonly_fullmem_support()
returns false. That is wrong because it just means that we do not know yet
if the potentially new SM supports sendonly joins.

Sendonly join was introduced in 2015 and all the Subnet managers have
supported it ever since. So there is no point in checking if a subnet
manager supports it.

Should an old opensm get a request for a sendonly join then the request
will fail. The code that is removed here accomodated that situation and
fell back to a full join.

Falling back to a full join is problematic in itself. The reason to use
the sendonly join was to reduce the traffic on the Infiniband fabric
otherwise one could have just stayed with the regular join.  So this patch
may cause users of very old opensms to discover that lots of traffic
needlessly crosses their IB fabrics.

Link: https://lore.kernel.org/r/alpine.DEB.2.22.394.2101281845160.13303@www.lameter.com
Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
2021-02-16 14:42:58 -04:00
..
ipoib.h RDMA/ipoib: Remove racy Subnet Manager sendonly join checks 2021-02-16 14:42:58 -04:00
ipoib_cm.c RDMA: Convert sysfs device * show functions to use sysfs_emit() 2020-10-26 19:53:21 -03:00
ipoib_ethtool.c RDMA/ipoib: Add 50Gb and 100Gb link speeds to ethtool 2020-11-02 15:48:56 -04:00
ipoib_fs.c RDMA/ipoib: Convert to use DEFINE_SEQ_ATTRIBUTE macro 2020-09-16 13:46:18 -03:00
ipoib_ib.c RDMA/ipoib: Fix ABBA deadlock with ipoib_reap_ah() 2020-07-02 10:46:06 -03:00
ipoib_main.c RDMA/ipoib: Remove racy Subnet Manager sendonly join checks 2021-02-16 14:42:58 -04:00
ipoib_multicast.c RDMA/ipoib: Remove racy Subnet Manager sendonly join checks 2021-02-16 14:42:58 -04:00
ipoib_netlink.c RDMA/ipoib: Set rtnl_link_ops for ipoib interfaces 2020-10-05 15:05:45 -03:00
ipoib_verbs.c RDMA/ipoib: Distribute cq completion vector better 2020-11-20 16:18:59 -04:00
ipoib_vlan.c RDMA: Convert sysfs device * show functions to use sysfs_emit() 2020-10-26 19:53:21 -03:00
Kconfig treewide: replace '---help---' in Kconfig files with 'help' 2020-06-14 01:57:21 +09:00
Makefile License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00