path: root/include/net/sch_generic.h
diff options
authorVlad Buslov <vladbu@mellanox.com>2019-02-11 10:55:32 +0200
committerDavid S. Miller <davem@davemloft.net>2019-02-12 13:41:32 -0500
commitc266f64dbfa2a970a13b0574246c0ddfec492365 (patch)
tree6159f9f536631d06b334732f7b3f0a2237a7f817 /include/net/sch_generic.h
parentisdn_v110: mark expected switch fall-through (diff)
net: sched: protect block state with mutex
Currently, tcf_block doesn't use any synchronization mechanisms to protect critical sections that manage lifetime of its chains. block->chain_list and multiple variables in tcf_chain that control its lifetime assume external synchronization provided by global rtnl lock. Converting chain reference counting to atomic reference counters is not possible because cls API uses multiple counters and flags to control chain lifetime, so all of them must be synchronized in chain get/put code. Use single per-block lock to protect block data and manage lifetime of all chains on the block. Always take block->lock when accessing chain_list. Chain get and put modify chain lifetime-management data and parent block's chain_list, so take the lock in these functions. Verify block->lock state with assertions in functions that expect to be called with the lock taken and are called from multiple places. Take block->lock when accessing filter_chain_list. In order to allow parallel update of rules on single block, move all calls to classifiers outside of critical sections protected by new block->lock. Rearrange chain get and put functions code to only access protected chain data while holding block lock: - Rearrange code to only access chain reference counter and chain action reference counter while holding block lock. - Extract code that requires block->lock from tcf_chain_destroy() into standalone tcf_chain_destroy() function that is called by __tcf_chain_put() in same critical section that changes chain reference counters. Signed-off-by: Vlad Buslov <vladbu@mellanox.com> Acked-by: Jiri Pirko <jiri@mellanox.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'include/net/sch_generic.h')
1 files changed, 5 insertions, 0 deletions
diff --git a/include/net/sch_generic.h b/include/net/sch_generic.h
index 7a4957599874..31b8ea66a47d 100644
--- a/include/net/sch_generic.h
+++ b/include/net/sch_generic.h
@@ -12,6 +12,7 @@
#include <linux/list.h>
#include <linux/refcount.h>
#include <linux/workqueue.h>
+#include <linux/mutex.h>
#include <net/gen_stats.h>
#include <net/rtnetlink.h>
@@ -352,6 +353,10 @@ struct tcf_chain {
struct tcf_block {
+ /* Lock protects tcf_block and lifetime-management data of chains
+ * attached to the block (refcnt, action_refcnt, explicitly_created).
+ */
+ struct mutex lock;
struct list_head chain_list;
u32 index; /* block index for shared blocks */
refcount_t refcnt;