linux-stable.git/net/openvswitch/flow_table.c, branch v5.8.7

net: openvswitch: introduce common code for flushing flows

2020-09-03T09:29:25+00:00

[ Upstream commit 1f3a090b9033f69de380c03db3ea1a1015c850cf ]

To avoid some issues, for example RCU usage warning and double free,
we should flush the flows under ovs_lock. This patch refactors
table_instance_destroy and introduces table_instance_flow_flush
which can be invoked by __dp_destroy or ovs_flow_tbl_flush.

Fixes: 50b0e61b32ee ("net: openvswitch: fix possible memleak on destroy flow-table")
Reported-by: Johan Knöös 
Reported-at: https://mail.openvswitch.org/pipermail/ovs-discuss/2020-August/050489.html
Signed-off-by: Tonghao Zhang 
Reviewed-by: Cong Wang 
Signed-off-by: David S. Miller 
Signed-off-by: Sasha Levin

net: openvswitch: use hlist_for_each_entry_rcu instead of hlist_for_each_entry

2020-04-03T00:48:12+00:00

The struct sw_flow is protected by RCU, when traversing them,
use hlist_for_each_entry_rcu.

Signed-off-by: Tonghao Zhang 
Tested-by: Greg Rose 
Reviewed-by: Greg Rose 
Signed-off-by: David S. Miller

flow_table.c: Use built-in RCU list checking

2020-02-18T20:46:27+00:00

hlist_for_each_entry_rcu() has built-in RCU and lock checking.

Pass cond argument to list_for_each_entry_rcu() to silence
false lockdep warning when CONFIG_PROVE_RCU_LIST is enabled
by default.

Signed-off-by: Madhuparna Bhowmik 
Signed-off-by: David S. Miller

net: openvswitch: fix possible memleak on destroy flow-table

2019-11-04T01:18:03+00:00

When we destroy the flow tables which may contain the flow_mask,
so release the flow mask struct.

Signed-off-by: Tonghao Zhang 
Tested-by: Greg Rose 
Acked-by: Pravin B Shelar 
Signed-off-by: David S. Miller

net: openvswitch: add likely in flow_lookup

2019-11-04T01:18:03+00:00

The most case *index < ma->max, and flow-mask is not NULL.
We add un/likely for performance.

Signed-off-by: Tonghao Zhang 
Tested-by: Greg Rose 
Acked-by: William Tu 
Acked-by: Pravin B Shelar 
Signed-off-by: David S. Miller

net: openvswitch: simplify the flow_hash

2019-11-04T01:18:03+00:00

Simplify the code and remove the unnecessary BUILD_BUG_ON.

Signed-off-by: Tonghao Zhang 
Tested-by: Greg Rose 
Acked-by: William Tu 
Acked-by: Pravin B Shelar 
Signed-off-by: David S. Miller

net: openvswitch: optimize flow-mask looking up

2019-11-04T01:18:03+00:00

The full looking up on flow table traverses all mask array.
If mask-array is too large, the number of invalid flow-mask
increase, performance will be drop.

One bad case, for example: M means flow-mask is valid and NULL
of flow-mask means deleted.

+-------------------------------------------+
| M | NULL | ...                  | NULL | M|
+-------------------------------------------+

In that case, without this patch, openvswitch will traverses all
mask array, because there will be one flow-mask in the tail. This
patch changes the way of flow-mask inserting and deleting, and the
mask array will be keep as below: there is not a NULL hole. In the
fast path, we can "break" "for" (not "continue") in flow_lookup
when we get a NULL flow-mask.

         "break"
            v
+-------------------------------------------+
| M | M |  NULL |...           | NULL | NULL|
+-------------------------------------------+

This patch don't optimize slow or control path, still using ma->max
to traverse. Slow path:
* tbl_mask_array_realloc
* ovs_flow_tbl_lookup_exact
* flow_mask_find

Signed-off-by: Tonghao Zhang 
Tested-by: Greg Rose 
Acked-by: Pravin B Shelar 
Signed-off-by: David S. Miller

net: openvswitch: optimize flow mask cache hash collision

2019-11-04T01:18:03+00:00

Port the codes to linux upstream and with little changes.

Pravin B Shelar, says:
| In case hash collision on mask cache, OVS does extra flow
| lookup. Following patch avoid it.

Link: https://github.com/openvswitch/ovs/commit/0e6efbe2712da03522532dc5e84806a96f6a0dd1
Signed-off-by: Tonghao Zhang 
Tested-by: Greg Rose 
Signed-off-by: Pravin B Shelar 
Signed-off-by: David S. Miller

net: openvswitch: shrink the mask array if necessary

2019-11-04T01:18:03+00:00

When creating and inserting flow-mask, if there is no available
flow-mask, we realloc the mask array. When removing flow-mask,
if necessary, we shrink mask array.

Signed-off-by: Tonghao Zhang 
Tested-by: Greg Rose 
Acked-by: William Tu 
Acked-by: Pravin B Shelar 
Signed-off-by: David S. Miller

net: openvswitch: convert mask list in mask array

2019-11-04T01:18:03+00:00

Port the codes to linux upstream and with little changes.

Pravin B Shelar, says:
| mask caches index of mask in mask_list. On packet recv OVS
| need to traverse mask-list to get cached mask. Therefore array
| is better for retrieving cached mask. This also allows better
| cache replacement algorithm by directly checking mask's existence.

Link: https://github.com/openvswitch/ovs/commit/d49fc3ff53c65e4eca9cabd52ac63396746a7ef5
Signed-off-by: Tonghao Zhang 
Tested-by: Greg Rose 
Acked-by: William Tu 
Signed-off-by: Pravin B Shelar 
Signed-off-by: David S. Miller