1. 31 Jul, 2015 7 commits
    • Jon Paul Maloy's avatar
      tipc: merge link->exec_mode and link->state into one FSM · 662921cd
      Jon Paul Maloy authored
      Until now, we have been handling link failover and synchronization
      by using an additional link state variable, "exec_mode". This variable
      is not independent of the link FSM state, something causing a risk of
      inconsistencies, apart from the fact that it clutters the code.
      
      The conditions are now in place to define a new link FSM that covers
      all existing use cases, including failover and synchronization, and
      eliminate the "exec_mode" field altogether. The FSM must also support
      non-atomic resetting of links, which will be introduced later.
      
      The new link FSM is shown below, with 7 states and 8 events.
      Only events leading to state change are shown as edges.
      
      +------------------------------------+
      |RESET_EVT                           |
      |                                    |
      |                             +--------------+
      |           +-----------------|   SYNCHING   |-----------------+
      |           |FAILURE_EVT      +--------------+   PEER_RESET_EVT|
      |           |                  A            |                  |
      |           |                  |            |                  |
      |           |                  |            |                  |
      |           |                  |SYNCH_      |SYNCH_            |
      |           |                  |BEGIN_EVT   |END_EVT           |
      |           |                  |            |                  |
      |           V                  |            V                  V
      |    +-------------+          +--------------+          +------------+
      |    |  RESETTING  |<---------|  ESTABLISHED |--------->| PEER_RESET |
      |    +-------------+ FAILURE_ +--------------+ PEER_    +------------+
      |           |        EVT        |    A         RESET_EVT       |
      |           |                   |    |                         |
      |           |                   |    |                         |
      |           |    +--------------+    |                         |
      |  RESET_EVT|    |RESET_EVT          |ESTABLISH_EVT            |
      |           |    |                   |                         |
      |           |    |                   |                         |
      |           V    V                   |                         |
      |    +-------------+          +--------------+        RESET_EVT|
      +--->|    RESET    |--------->| ESTABLISHING |<----------------+
           +-------------+ PEER_    +--------------+
            |           A  RESET_EVT       |
            |           |                  |
            |           |                  |
            |FAILOVER_  |FAILOVER_         |FAILOVER_
            |BEGIN_EVT  |END_EVT           |BEGIN_EVT
            |           |                  |
            V           |                  |
           +-------------+                 |
           | FAILINGOVER |<----------------+
           +-------------+
      
      These changes are fully backwards compatible.
      Tested-by: default avatarYing Xue <ying.xue@windriver.com>
      Signed-off-by: default avatarJon Maloy <jon.maloy@ericsson.com>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      662921cd
    • Jon Paul Maloy's avatar
      tipc: move protocol message sending away from link FSM · 5045f7b9
      Jon Paul Maloy authored
      The implementation of the link FSM currently takes decisions about and
      sends out link protocol messages. This is unnecessary, since such
      actions are not the result of any link state change, and are even
      decided based on non-FSM state information ("silent_intv_cnt").
      
      We now move the sending of unicast link protocol messages to the
      function tipc_link_timeout(), and the initial broadcast synchronization
      message to tipc_node_link_up(). The latter is done because a link
      instance should not need to know whether it is the first or second
      link to a destination. Such information is now restricted to and
      handled by the link aggregation layer in node.c
      Tested-by: default avatarYing Xue <ying.xue@windriver.com>
      Signed-off-by: default avatarJon Maloy <jon.maloy@ericsson.com>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      5045f7b9
    • Jon Paul Maloy's avatar
      tipc: move link synch and failover to link aggregation level · 6e498158
      Jon Paul Maloy authored
      Link failover and synchronization have until now been handled by the
      links themselves, forcing them to have knowledge about and to access
      parallel links in order to make the two algorithms work correctly.
      
      In this commit, we move the control part of this functionality to the
      link aggregation level in node.c, which is the right location for this.
      As a result, the two algorithms become easier to follow, and the link
      implementation becomes simpler.
      Tested-by: default avatarYing Xue <ying.xue@windriver.com>
      Signed-off-by: default avatarJon Maloy <jon.maloy@ericsson.com>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      6e498158
    • Jon Paul Maloy's avatar
      tipc: extend node FSM · 66996b6c
      Jon Paul Maloy authored
      In the next commit, we will move link synch/failover orchestration to
      the link aggregation level. In order to do this, we first need to extend
      the node FSM with two more states, NODE_SYNCHING and NODE_FAILINGOVER,
      plus four new events to enter and leave those states.
      
      This commit introduces this change, without yet making use of it.
      The node FSM now looks as follows:
      
                                 +-----------------------------------------+
                                 |                            PEER_DOWN_EVT|
                                 |                                         |
        +------------------------+----------------+                        |
        |SELF_DOWN_EVT           |                |                        |
        |                        |                |                        |
        |              +-----------+          +-----------+                |
        |              |NODE_      |          |NODE_      |                |
        |   +----------|FAILINGOVER|<---------|SYNCHING   |------------+   |
        |   |SELF_     +-----------+ FAILOVER_+-----------+    PEER_   |   |
        |   |DOWN_EVT   |         A  BEGIN_EVT A         |     DOWN_EVT|   |
        |   |           |         |            |         |             |   |
        |   |           |         |            |         |             |   |
        |   |           |FAILOVER_|FAILOVER_   |SYNCH_   |SYNCH_       |   |
        |   |           |END_EVT  |BEGIN_EVT   |BEGIN_EVT|END_EVT      |   |
        |   |           |         |            |         |             |   |
        |   |           |         |            |         |             |   |
        |   |           |        +--------------+        |             |   |
        |   |           +------->|   SELF_UP_   |<-------+             |   |
        |   |   +----------------|   PEER_UP    |------------------+   |   |
        |   |   |SELF_DOWN_EVT   +--------------+     PEER_DOWN_EVT|   |   |
        |   |   |                   A          A                   |   |   |
        |   |   |                   |          |                   |   |   |
        |   |   |        PEER_UP_EVT|          |SELF_UP_EVT        |   |   |
        |   |   |                   |          |                   |   |   |
        V   V   V                   |          |                   V   V   V
      +------------+       +-----------+    +-----------+       +------------+
      |SELF_DOWN_  |       |SELF_UP_   |    |PEER_UP_   |       |PEER_DOWN   |
      |PEER_LEAVING|<------|PEER_COMING|    |SELF_COMING|------>|SELF_LEAVING|
      +------------+ SELF_ +-----------+    +-----------+ PEER_ +------------+
             |       DOWN_EVT       A          A          DOWN_EVT     |
             |                      |          |                       |
             |                      |          |                       |
             |           SELF_UP_EVT|          |PEER_UP_EVT            |
             |                      |          |                       |
             |                      |          |                       |
             |PEER_DOWN_EVT       +--------------+        SELF_DOWN_EVT|
             +------------------->|  SELF_DOWN_  |<--------------------+
                                  |  PEER_DOWN   |
                                  +--------------+
      Tested-by: default avatarYing Xue <ying.xue@windriver.com>
      Signed-off-by: default avatarJon Maloy <jon.maloy@ericsson.com>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      66996b6c
    • Jon Paul Maloy's avatar
      tipc: reverse call order for link_reset()->node_link_down() · 655fb243
      Jon Paul Maloy authored
      In many cases the call order when a link is reset goes as follows:
      tipc_node_xx()->tipc_link_reset()->tipc_node_link_down()
      
      This is not the right order if we want the node to be in control,
      so in this commit we change the order to:
      tipc_node_xx()->tipc_node_link_down()->tipc_link_reset()
      
      The fact that tipc_link_reset() now is called from only one
      location with a well-defined state will also facilitate later
      simplifications of tipc_link_reset() and the link FSM.
      Tested-by: default avatarYing Xue <ying.xue@windriver.com>
      Signed-off-by: default avatarJon Maloy <jon.maloy@ericsson.com>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      655fb243
    • Jon Paul Maloy's avatar
      tipc: move all link_reset() calls to link aggregation level · 6144a996
      Jon Paul Maloy authored
      In line with our effort to let the node level have full control over
      its links, we want to move all link reset calls from link.c to node.c.
      Some of the calls can be moved by simply moving the calling function,
      when this is the right thing to do. For the remaining calls we use
      the now established technique of returning a TIPC_LINK_DOWN_EVT
      flag from tipc_link_rcv(), whereafter we perform the reset call when
      the call returns.
      
      This change serves as a preparation for the coming commits.
      Tested-by: default avatarYing Xue <ying.xue@windriver.com>
      Signed-off-by: default avatarJon Maloy <jon.maloy@ericsson.com>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      6144a996
    • Jon Paul Maloy's avatar
      tipc: eliminate function tipc_link_activate() · cbeb83ca
      Jon Paul Maloy authored
      The function tipc_link_activate() is redundant, since it mostly performs
      settings that have already been done in a preceding tipc_link_reset().
      
      There are three exceptions to this:
      - The actual state change to TIPC_LINK_WORKING. This should anyway be done
        in the FSM, and not in a separate function.
      - Registration of the link with the bearer. This should be done by the
        node, since we don't want the link to have any knowledge about its
        specific bearer.
      - Call to tipc_node_link_up() for user access registration. With the new
        role distribution between link aggregation and link level this becomes
        the wrong call order; tipc_node_link_up() should instead be called
        directly as a result of a TIPC_LINK_UP event, hence by the node itself.
      
      This commit implements those changes.
      Tested-by: default avatarYing Xue <ying.xue@windriver.com>
      Signed-off-by: default avatarJon Maloy <jon.maloy@ericsson.com>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      cbeb83ca
  2. 30 Jul, 2015 33 commits