linux/drivers/infiniband/ulp
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 RDMA/ipoib: Remove racy Subnet Manager sendonly join checks 2021-02-16 14:42:58 -04:00
iser IB/iser: Simplify prot_caps setting 2021-01-19 20:02:07 -04:00
isert IB/isert: Simplify signature cap check 2021-01-18 16:59:04 -04:00
opa_vnic RDMA: Convert comma to semicolon 2021-01-07 13:53:41 -04:00
rtrs RDMA/rtrs: Fix KASAN: stack-out-of-bounds bug 2021-01-15 15:25:10 -04:00
srp RDMA: Convert various random sprintf sysfs _show uses to sysfs_emit 2020-10-30 21:03:52 -03:00
srpt RDMA 5.11 pull request 2020-12-16 13:42:26 -08:00
Makefile RDMA/rtrs: include client and server modules into kernel compilation 2020-05-17 18:57:15 -03:00