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  1. 31 Jul, 2015 9 commits
    • Jon Paul Maloy's avatar
      tipc: make resetting of links non-atomic · 598411d7
      Jon Paul Maloy authored 
      In order to facilitate future improvements to the locking structure, we
want to make resetting and establishing of links non-atomic. I.e., the
functions tipc_node_link_up() and tipc_node_link_down() should be called
from outside the node lock context, and grab/release the node lock
themselves. This requires that we can freeze the link state from the
moment it is set to RESETTING or PEER_RESET in one lock context until
it is set to RESET or ESTABLISHING in a later context. The recently
introduced link FSM makes this possible, so we are now ready to introduce
the above change.

This commit implements this.
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>
      598411d7
    • Jon Paul Maloy's avatar
      tipc: move received discovery data evaluation inside node.c · cf148816
      Jon Paul Maloy authored 
      The node lock is currently grabbed and and released in the function
tipc_disc_rcv() in the file discover.c. As a preparation for the next
commits, we need to move this node lock handling, along with the code
area it is covering, to node.c.

This commit introduces this change.
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>
      cf148816
    • 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
  3. 30 Jul, 2015 31 commits
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