From: Jiri Pirko <j...@mellanox.com> Ido says:
In kernel 4.9 the switchdev-specific FIB offload mechanism was replaced by a new FIB notification chain to which modules could register in order to be notified about the addition and deletion of FIB entries. The motivation for this change was that switchdev drivers need to be able to reflect the entire FIB table and not only FIBs configured on top of the port netdevs themselves. This is useful in case of in-band management. The fundamental problem with this approach is that upon registration listeners lose all the information previously sent in the chain and thus have an incomplete view of the FIB tables, which can result in packet loss. This patchset fixes that by introducing a new API to dump the FIB tables. The entire dump process is done under RCU and thus the FIB notification chain is converted to be atomic. The listeners are modified accordingly. This is done in the first seven patches. The eighth and ninth patches add a change sequence counter to ensure the integrity of the FIB dump and a sysctl to set the number of retries, respectively. The tenth patch finally introduces the FIB dump itself. The last two patches modify current listeners of the FIB notification chain to invoke the dump during their init. v2->v3: - Add sysctl to set the number of FIB dump retries (Hannes Frederic Sowa). - Read the sequence counter under RTNL to ensure synchronization between the dump process and other processes changing the routing tables (Hannes Frederic Sowa). - Pass a callback to the dump function to be executed prior to a retry. - Limit the dump to a single net namespace. v1->v2: - Add a sequence counter to ensure the integrity of the FIB dump (David S. Miller, Hannes Frederic Sowa). - Protect notifications from re-ordering in listeners by using an ordered workqueue (Hannes Frederic Sowa). - Introduce fib_info_hold() (Jiri Pirko). - Relieve rocker from the need to invoke the FIB dump by registering to the FIB notification chain prior to ports creation. Ido Schimmel (12): ipv4: fib: Export free_fib_info() ipv4: fib: Add fib_info_hold() helper mlxsw: core: Create an ordered workqueue for FIB offload mlxsw: spectrum_router: Implement FIB offload in deferred work rocker: Create an ordered workqueue for FIB offload rocker: Implement FIB offload in deferred work ipv4: fib: Convert FIB notification chain to be atomic ipv4: fib: Allow for consistent FIB dumping ipv4: fib: Add sysctl to limit number of FIB dump retries ipv4: fib: Add an API to request a FIB dump mlxsw: spectrum_router: Request a dump of FIB tables during init rocker: Register FIB notifier before creating ports Documentation/networking/ip-sysctl.txt | 8 ++ drivers/net/ethernet/mellanox/mlxsw/core.c | 22 +++ drivers/net/ethernet/mellanox/mlxsw/core.h | 2 + .../net/ethernet/mellanox/mlxsw/spectrum_router.c | 95 +++++++++++-- drivers/net/ethernet/rocker/rocker.h | 1 + drivers/net/ethernet/rocker/rocker_main.c | 78 +++++++++-- drivers/net/ethernet/rocker/rocker_ofdpa.c | 1 + include/net/ip_fib.h | 9 ++ include/net/netns/ipv4.h | 4 + net/ipv4/fib_frontend.c | 3 + net/ipv4/fib_semantics.c | 1 + net/ipv4/fib_trie.c | 147 ++++++++++++++++++++- net/ipv4/sysctl_net_ipv4.c | 7 + 13 files changed, 352 insertions(+), 26 deletions(-) -- 2.7.4
