path: root/include/net/sch_generic.h
diff options
authorJohn Hurley <john.hurley@netronome.com>2019-11-02 14:17:47 +0000
committerDavid S. Miller <davem@davemloft.net>2019-11-05 17:47:26 -0800
commit59eb87cb52c9f7164804bc8639c4d03ba9b0c169 (patch)
tree086022aca0f7a739d602c65c661e8d99f45239b3 /include/net/sch_generic.h
parentnet: hns3: Use the correct style for SPDX License Identifier (diff)
net: sched: prevent duplicate flower rules from tcf_proto destroy race
When a new filter is added to cls_api, the function tcf_chain_tp_insert_unique() looks up the protocol/priority/chain to determine if the tcf_proto is duplicated in the chain's hashtable. It then creates a new entry or continues with an existing one. In cls_flower, this allows the function fl_ht_insert_unque to determine if a filter is a duplicate and reject appropriately, meaning that the duplicate will not be passed to drivers via the offload hooks. However, when a tcf_proto is destroyed it is removed from its chain before a hardware remove hook is hit. This can lead to a race whereby the driver has not received the remove message but duplicate flows can be accepted. This, in turn, can lead to the offload driver receiving incorrect duplicate flows and out of order add/delete messages. Prevent duplicates by utilising an approach suggested by Vlad Buslov. A hash table per block stores each unique chain/protocol/prio being destroyed. This entry is only removed when the full destroy (and hardware offload) has completed. If a new flow is being added with the same identiers as a tc_proto being detroyed, then the add request is replayed until the destroy is complete. Fixes: 8b64678e0af8 ("net: sched: refactor tp insert/delete for concurrent execution") Signed-off-by: John Hurley <john.hurley@netronome.com> Signed-off-by: Vlad Buslov <vladbu@mellanox.com> Reviewed-by: Simon Horman <simon.horman@netronome.com> Reported-by: Louis Peens <louis.peens@netronome.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'include/net/sch_generic.h')
1 files changed, 4 insertions, 0 deletions
diff --git a/include/net/sch_generic.h b/include/net/sch_generic.h
index 637548d54b3e..d80acda231ae 100644
--- a/include/net/sch_generic.h
+++ b/include/net/sch_generic.h
@@ -15,6 +15,7 @@
#include <linux/mutex.h>
#include <linux/rwsem.h>
#include <linux/atomic.h>
+#include <linux/hashtable.h>
#include <net/gen_stats.h>
#include <net/rtnetlink.h>
#include <net/flow_offload.h>
@@ -362,6 +363,7 @@ struct tcf_proto {
bool deleting;
refcount_t refcnt;
struct rcu_head rcu;
+ struct hlist_node destroy_ht_node;
struct qdisc_skb_cb {
@@ -414,6 +416,8 @@ struct tcf_block {
struct list_head filter_chain_list;
} chain0;
struct rcu_head rcu;
+ DECLARE_HASHTABLE(proto_destroy_ht, 7);
+ struct mutex proto_destroy_lock; /* Lock for proto_destroy hashtable. */