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  1. 27 7月, 2016 2 次提交
  3. 12 7月, 2016 1 次提交
  5. 16 6月, 2016 2 次提交
    • Y
      tipc: fix suspicious RCU usage · 66d95b67
      由 Ying Xue 提交于 
      When run tipcTS&tipcTC test suite, the following complaint appears:

[   56.926168] ===============================
[   56.926169] [ INFO: suspicious RCU usage. ]
[   56.926171] 4.7.0-rc1+ #160 Not tainted
[   56.926173] -------------------------------
[   56.926174] net/tipc/bearer.c:408 suspicious rcu_dereference_protected() usage!
[   56.926175]
[   56.926175] other info that might help us debug this:
[   56.926175]
[   56.926177]
[   56.926177] rcu_scheduler_active = 1, debug_locks = 1
[   56.926179] 3 locks held by swapper/4/0:
[   56.926180]  #0:  (((&req->timer))){+.-...}, at: [<ffffffff810e79b5>] call_timer_fn+0x5/0x340
[   56.926203]  #1:  (&(&req->lock)->rlock){+.-...}, at: [<ffffffffa000c29b>] disc_timeout+0x1b/0xd0 [tipc]
[   56.926212]  #2:  (rcu_read_lock){......}, at: [<ffffffffa00055e0>] tipc_bearer_xmit_skb+0xb0/0x2e0 [tipc]
[   56.926218]
[   56.926218] stack backtrace:
[   56.926221] CPU: 4 PID: 0 Comm: swapper/4 Not tainted 4.7.0-rc1+ #160
[   56.926222] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2007
[   56.926224]  0000000000000000 ffff880016803d28 ffffffff813c4423 ffff8800154252c0
[   56.926227]  0000000000000001 ffff880016803d58 ffffffff810b7512 ffff8800124d8120
[   56.926230]  ffff880013f8a160 ffff8800132b5ccc ffff8800124d8120 ffff880016803d88
[   56.926234] Call Trace:
[   56.926235]  <IRQ>  [<ffffffff813c4423>] dump_stack+0x67/0x94
[   56.926250]  [<ffffffff810b7512>] lockdep_rcu_suspicious+0xe2/0x120
[   56.926256]  [<ffffffffa00051f1>] tipc_l2_send_msg+0x131/0x1c0 [tipc]
[   56.926261]  [<ffffffffa000567c>] tipc_bearer_xmit_skb+0x14c/0x2e0 [tipc]
[   56.926266]  [<ffffffffa00055e0>] ? tipc_bearer_xmit_skb+0xb0/0x2e0 [tipc]
[   56.926273]  [<ffffffffa000c280>] ? tipc_disc_init_msg+0x1f0/0x1f0 [tipc]
[   56.926278]  [<ffffffffa000c280>] ? tipc_disc_init_msg+0x1f0/0x1f0 [tipc]
[   56.926283]  [<ffffffffa000c2d6>] disc_timeout+0x56/0xd0 [tipc]
[   56.926288]  [<ffffffff810e7a68>] call_timer_fn+0xb8/0x340
[   56.926291]  [<ffffffff810e79b5>] ? call_timer_fn+0x5/0x340
[   56.926296]  [<ffffffffa000c280>] ? tipc_disc_init_msg+0x1f0/0x1f0 [tipc]
[   56.926300]  [<ffffffff810e8f4a>] run_timer_softirq+0x23a/0x390
[   56.926306]  [<ffffffff810f89ff>] ? clockevents_program_event+0x7f/0x130
[   56.926316]  [<ffffffff819727c3>] __do_softirq+0xc3/0x4a2
[   56.926323]  [<ffffffff8106ba5a>] irq_exit+0x8a/0xb0
[   56.926327]  [<ffffffff81972456>] smp_apic_timer_interrupt+0x46/0x60
[   56.926331]  [<ffffffff81970a49>] apic_timer_interrupt+0x89/0x90
[   56.926333]  <EOI>  [<ffffffff81027fda>] ? default_idle+0x2a/0x1a0
[   56.926340]  [<ffffffff81027fd8>] ? default_idle+0x28/0x1a0
[   56.926342]  [<ffffffff810289cf>] arch_cpu_idle+0xf/0x20
[   56.926345]  [<ffffffff810adf0f>] default_idle_call+0x2f/0x50
[   56.926347]  [<ffffffff810ae145>] cpu_startup_entry+0x215/0x3e0
[   56.926353]  [<ffffffff81040ad9>] start_secondary+0xf9/0x100

The warning appears as rtnl_dereference() is wrongly used in
tipc_l2_send_msg() under RCU read lock protection. Instead the proper
usage should be that rcu_dereference_rtnl() is called here.

Fixes: 5b7066c3 ("tipc: stricter filtering of packets in bearer layer")
Acked-by: NJon Maloy <jon.maloy@ericsson.com>
Signed-off-by: NYing Xue <ying.xue@windriver.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      66d95b67
    • J
      tipc: add neighbor monitoring framework · 35c55c98
      由 Jon Paul Maloy 提交于 
      TIPC based clusters are by default set up with full-mesh link
connectivity between all nodes. Those links are expected to provide
a short failure detection time, by default set to 1500 ms. Because
of this, the background load for neighbor monitoring in an N-node
cluster increases with a factor N on each node, while the overall
monitoring traffic through the network infrastructure increases at
a ~(N * (N - 1)) rate. Experience has shown that such clusters don't
scale well beyond ~100 nodes unless we significantly increase failure
discovery tolerance.

This commit introduces a framework and an algorithm that drastically
reduces this background load, while basically maintaining the original
failure detection times across the whole cluster. Using this algorithm,
background load will now grow at a rate of ~(2 * sqrt(N)) per node, and
at ~(2 * N * sqrt(N)) in traffic overhead. As an example, each node will
now have to actively monitor 38 neighbors in a 400-node cluster, instead
of as before 399.

This "Overlapping Ring Supervision Algorithm" is completely distributed
and employs no centralized or coordinated state. It goes as follows:

- Each node makes up a linearly ascending, circular list of all its N
  known neighbors, based on their TIPC node identity. This algorithm
  must be the same on all nodes.

- The node then selects the next M = sqrt(N) - 1 nodes downstream from
  itself in the list, and chooses to actively monitor those. This is
  called its "local monitoring domain".

- It creates a domain record describing the monitoring domain, and
  piggy-backs this in the data area of all neighbor monitoring messages
  (LINK_PROTOCOL/STATE) leaving that node. This means that all nodes in
  the cluster eventually (default within 400 ms) will learn about
  its monitoring domain.

- Whenever a node discovers a change in its local domain, e.g., a node
  has been added or has gone down, it creates and sends out a new
  version of its node record to inform all neighbors about the change.

- A node receiving a domain record from anybody outside its local domain
  matches this against its own list (which may not look the same), and
  chooses to not actively monitor those members of the received domain
  record that are also present in its own list. Instead, it relies on
  indications from the direct monitoring nodes if an indirectly
  monitored node has gone up or down. If a node is indicated lost, the
  receiving node temporarily activates its own direct monitoring towards
  that node in order to confirm, or not, that it is actually gone.

- Since each node is actively monitoring sqrt(N) downstream neighbors,
  each node is also actively monitored by the same number of upstream
  neighbors. This means that all non-direct monitoring nodes normally
  will receive sqrt(N) indications that a node is gone.

- A major drawback with ring monitoring is how it handles failures that
  cause massive network partitionings. If both a lost node and all its
  direct monitoring neighbors are inside the lost partition, the nodes in
  the remaining partition will never receive indications about the loss.
  To overcome this, each node also chooses to actively monitor some
  nodes outside its local domain. Those nodes are called remote domain
  "heads", and are selected in such a way that no node in the cluster
  will be more than two direct monitoring hops away. Because of this,
  each node, apart from monitoring the member of its local domain, will
  also typically monitor sqrt(N) remote head nodes.

- As an optimization, local list status, domain status and domain
  records are marked with a generation number. This saves senders from
  unnecessarily conveying  unaltered domain records, and receivers from
  performing unneeded re-adaptations of their node monitoring list, such
  as re-assigning domain heads.

- As a measure of caution we have added the possibility to disable the
  new algorithm through configuration. We do this by keeping a threshold
  value for the cluster size; a cluster that grows beyond this value
  will switch from full-mesh to ring monitoring, and vice versa when
  it shrinks below the value. This means that if the threshold is set to
  a value larger than any anticipated cluster size (default size is 32)
  the new algorithm is effectively disabled. A patch set for altering the
  threshold value and for listing the table contents will follow shortly.

- This change is fully backwards compatible.
Acked-by: NYing Xue <ying.xue@windriver.com>
Signed-off-by: NJon Maloy <jon.maloy@ericsson.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      35c55c98
  7. 08 4月, 2016 2 次提交
    • J
      tipc: stricter filtering of packets in bearer layer · 5b7066c3
      由 Jon Paul Maloy 提交于 
      Resetting a bearer/interface, with the consequence of resetting all its
pertaining links, is not an atomic action. This becomes particularly
evident in very large clusters, where a lot of traffic may happen on the
remaining links while we are busy shutting them down. In extreme cases,
we may even see links being re-created and re-established before we are
finished with the job.

To solve this, we now introduce a solution where we temporarily detach
the bearer from the interface when the bearer is reset. This inhibits
all packet reception, while sending still is possible. For the latter,
we use the fact that the device's user pointer now is zero to filter out
which packets can be sent during this situation; i.e., outgoing RESET
messages only.  This filtering serves to speed up the neighbors'
detection of the loss event, and saves us from unnecessary probing.
Acked-by: NYing Xue <ying.xue@windriver.com>
Signed-off-by: NJon Maloy <jon.maloy@ericsson.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      5b7066c3
    • J
      tipc: eliminate buffer leak in bearer layer · 4e801fa1
      由 Jon Paul Maloy 提交于 
      When enabling a bearer we create a 'neigbor discoverer' instance by
calling the function tipc_disc_create() before the bearer is actually
registered in the list of enabled bearers. Because of this, the very
first discovery broadcast message, created by the mentioned function,
is lost, since it cannot find any valid bearer to use. Furthermore,
the used send function, tipc_bearer_xmit_skb() does not free the given
buffer when it cannot find a  bearer, resulting in the leak of exactly
one send buffer each time a bearer is enabled.

This commit fixes this problem by introducing two changes:

1) Instead of attemting to send the discovery message directly, we let
   tipc_disc_create() return the discovery buffer to the calling
   function, tipc_enable_bearer(), so that the latter can send it
   when the enabling sequence is finished.

2) In tipc_bearer_xmit_skb(), as well as in the two other transmit
   functions at the bearer layer, we now free the indicated buffer or
   buffer chain when a valid bearer cannot be found.
Acked-by: NYing Xue <ying.xue@windriver.com>
Signed-off-by: NJon Maloy <jon.maloy@ericsson.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      4e801fa1
  9. 08 3月, 2016 1 次提交
  11. 21 11月, 2015 1 次提交
  13. 24 10月, 2015 5 次提交
  15. 16 10月, 2015 1 次提交
    • J
      tipc: send out RESET immediately when link goes down · 282b3a05
      由 Jon Paul Maloy 提交于 
      When a link is taken down because of a node local event, such as
disabling of a bearer or an interface, we currently leave it to the
peer node to discover the broken communication. The default time for
such failure discovery is 1.5-2 seconds.

If we instead allow the terminating link endpoint to send out a RESET
message at the moment it is reset, we can achieve the impression that
both endpoints are going down instantly. Since this is a very common
scenario, we find it worthwhile to make this small modification.

Apart from letting the link produce the said message, we also have to
ensure that the interface is able to transmit it before TIPC is
detached. We do this by performing the disabling of a bearer in three
steps:

1) Disable reception of TIPC packets from the interface in question.
2) Take down the links, while allowing them so send out a RESET message.
3) Disable transmission of TIPC packets on the interface.

Apart from this, we now have to react on the NETDEV_GOING_DOWN event,
instead of as currently the NEDEV_DOWN event, to ensure that such
transmission is possible during the teardown phase.
Signed-off-by: NJon Maloy <jon.maloy@ericsson.com>
Acked-by: NYing Xue <ying.xue@windriver.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      282b3a05
  17. 31 7月, 2015 1 次提交
  19. 21 7月, 2015 1 次提交
    • J
      tipc: make media xmit call outside node spinlock context · af9b028e
      由 Jon Paul Maloy 提交于 
      Currently, message sending is performed through a deep call chain,
where the node spinlock is grabbed and held during a significant
part of the transmission time. This is clearly detrimental to
overall throughput performance; it would be better if we could send
the message after the spinlock has been released.

In this commit, we do instead let the call revert on the stack after
the buffer chain has been added to the transmission queue, whereafter
clones of the buffers are transmitted to the device layer outside the
spinlock scope.

As a further step in our effort to separate the roles of the node
and link entities we also move the function tipc_link_xmit() to
node.c, and rename it to tipc_node_xmit().
Reviewed-by: NYing Xue <ying.xue@windriver.com>
Signed-off-by: NJon Maloy <jon.maloy@ericsson.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      af9b028e
  21. 15 5月, 2015 1 次提交
  23. 10 5月, 2015 1 次提交
  25. 30 4月, 2015 1 次提交
  27. 11 3月, 2015 1 次提交
    • J
      tipc: ensure that idle links are deleted when a bearer is disabled · 169bf912
      由 Jon Paul Maloy 提交于 
      commit afaa3f65
(tipc: purge links when bearer is disabled) was an attempt to resolve
a problem that turned out to have a more profound reason.

When we disable a bearer, we delete all its pertaining links if
there is no other bearer to perform failover to, or if the module
is shutting down. In case there are dual bearers, we wait with
deleting links until the failover procedure is finished.

However, this misses the case when a link on the removed bearer
was already down, so that there will be no failover procedure to
finish the link delete. This causes confusion if a new bearer is
added to replace the removed one, and also entails a small memory
leak.

This commit takes the current state of the link into account when
deciding when to delete it, and also reverses the above-mentioned
commit.
Reviewed-by: NErik Hugne <erik.hugne@ericsson.com>
Signed-off-by: NJon Maloy <jon.maloy@ericsson.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      169bf912
  29. 06 3月, 2015 1 次提交
  31. 28 2月, 2015 1 次提交
  33. 10 2月, 2015 6 次提交
  35. 13 1月, 2015 5 次提交
  37. 25 11月, 2014 1 次提交
  39. 22 11月, 2014 5 次提交