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authorHoang Huu Le2020-06-17 13:56:05 +0700
committerDavid S. Miller2020-06-17 08:53:34 -0700
commitcad2929dc4321b1f237767e9bd271b61a2eaa752 (patch)
treeaa1506f069b0c3d49036df6bf05f32dec2fb4964 /net/tipc/bcast.c
parent69119673bd50b176ded34032fadd41530fb5af21 (diff)
tipc: update a binding service via broadcast
Currently, updating binding table (add service binding to name table/withdraw a service binding) is being sent over replicast. However, if we are scaling up clusters to > 100 nodes/containers this method is less affection because of looping through nodes in a cluster one by one. It is worth to use broadcast to update a binding service. This way, the binding table can be updated on all peer nodes in one shot. Broadcast is used when all peer nodes, as indicated by a new capability flag TIPC_NAMED_BCAST, support reception of this message type. Four problems need to be considered when introducing this feature. 1) When establishing a link to a new peer node we still update this by a unicast 'bulk' update. This may lead to race conditions, where a later broadcast publication/withdrawal bypass the 'bulk', resulting in disordered publications, or even that a withdrawal may arrive before the corresponding publication. We solve this by adding an 'is_last_bulk' bit in the last bulk messages so that it can be distinguished from all other messages. Only when this message has arrived do we open up for reception of broadcast publications/withdrawals. 2) When a first legacy node is added to the cluster all distribution will switch over to use the legacy 'replicast' method, while the opposite happens when the last legacy node leaves the cluster. This entails another risk of message disordering that has to be handled. We solve this by adding a sequence number to the broadcast/replicast messages, so that disordering can be discovered and corrected. Note however that we don't need to consider potential message loss or duplication at this protocol level. 3) Bulk messages don't contain any sequence numbers, and will always arrive in order. Hence we must exempt those from the sequence number control and deliver them unconditionally. We solve this by adding a new 'is_bulk' bit in those messages so that they can be recognized. 4) Legacy messages, which don't contain any new bits or sequence numbers, but neither can arrive out of order, also need to be exempt from the initial synchronization and sequence number check, and delivered unconditionally. Therefore, we add another 'is_not_legacy' bit to all new messages so that those can be distinguished from legacy messages and the latter delivered directly. v1->v2: - fix warning issue reported by kbuild test robot <lkp@intel.com> - add santiy check to drop the publication message with a sequence number that is lower than the agreed synch point Signed-off-by: kernel test robot <lkp@intel.com> Signed-off-by: Hoang Huu Le <hoang.h.le@dektech.com.au> Acked-by: Jon Maloy <jmaloy@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/tipc/bcast.c')
-rw-r--r--net/tipc/bcast.c6
1 files changed, 3 insertions, 3 deletions
diff --git a/net/tipc/bcast.c b/net/tipc/bcast.c
index 383f87bc1061..940d176e0e87 100644
--- a/net/tipc/bcast.c
+++ b/net/tipc/bcast.c
@@ -250,8 +250,8 @@ static void tipc_bcast_select_xmit_method(struct net *net, int dests,
* Consumes the buffer chain.
* Returns 0 if success, otherwise errno: -EHOSTUNREACH,-EMSGSIZE
*/
-static int tipc_bcast_xmit(struct net *net, struct sk_buff_head *pkts,
- u16 *cong_link_cnt)
+int tipc_bcast_xmit(struct net *net, struct sk_buff_head *pkts,
+ u16 *cong_link_cnt)
{
struct tipc_link *l = tipc_bc_sndlink(net);
struct sk_buff_head xmitq;
@@ -752,7 +752,7 @@ void tipc_nlist_purge(struct tipc_nlist *nl)
nl->local = false;
}
-u32 tipc_bcast_get_broadcast_mode(struct net *net)
+u32 tipc_bcast_get_mode(struct net *net)
{
struct tipc_bc_base *bb = tipc_bc_base(net);