linux/drivers/infiniband
Parav Pandit 6b57cea922 IB/core: Let IB core distribute cache update events
Currently when the low level driver notifies Pkey, GID, and port change
events they are notified to the registered handlers in the order they are
registered.

IB core and other ULPs such as IPoIB are interested in GID, LID, Pkey
change events.

Since all GID queries done by ULPs are serviced by IB core, and the IB
core deferes cache updates to a work queue, it is possible for other
clients to see stale cache data when they handle their own events.

For example, the below call tree shows how ipoib will call
rdma_query_gid() concurrently with the update to the cache sitting in the
WQ.

mlx5_ib_handle_event()
  ib_dispatch_event()
    ib_cache_event()
       queue_work() -> slow cache update

    [..]
    ipoib_event()
     queue_work()
       [..]
       work handler
         ipoib_ib_dev_flush_light()
           __ipoib_ib_dev_flush()
              ipoib_dev_addr_changed_valid()
                rdma_query_gid() <- Returns old GID, cache not updated.

Move all the event dispatch to a work queue so that the cache update is
always done before any clients are notified.

Fixes: f35faa4ba9 ("IB/core: Simplify ib_query_gid to always refer to cache")
Link: https://lore.kernel.org/r/20191212113024.336702-3-leon@kernel.org
Signed-off-by: Parav Pandit <parav@mellanox.com>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Reviewed-by: Jason Gunthorpe <jgg@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
2020-01-07 20:18:10 -04:00
..
core IB/core: Let IB core distribute cache update events 2020-01-07 20:18:10 -04:00
hw IB/mlx5: Do reverse sequence during device removal 2020-01-07 20:18:10 -04:00
sw RDMA/rxe: Fix error type of mmap_offset 2020-01-03 19:43:51 -04:00
ulp IB/iser: use true,false for bool variable 2020-01-03 19:13:59 -04:00
Kconfig RDMA/iw_cxgb3: Remove the iw_cxgb3 module from kernel 2019-10-04 15:08:59 -03:00
Makefile treewide: Add SPDX license identifier - Makefile/Kconfig 2019-05-21 10:50:46 +02:00