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* tipc: update node FSM when peer RESET message is receivedJon Paul Maloy2015-10-151-2/+5
| | | | | | | | | | | | | | | | | | | | | | | The change made in the previous commit revealed a small flaw in the way the node FSM is updated. When the function tipc_node_link_down() is called for the last link to a node, we should check whether this was caused by a local reset or by a received RESET message from the peer. In the latter case, we can directly issue a PEER_LOST_CONTACT_EVT to the node FSM, so that it is ready to re-establish contact. If this is not done, the peer node will sometimes have to go through a second establish cycle before the link becomes stable. We fix this in this commit by conditionally issuing the mentioned event in the function tipc_node_link_down(). We also move LINK_RESET FSM even away from the link_reset() function and into the caller function, partially because it is easier to follow the code when state changes are gathered at a limited number of locations, partially because there will be cases in future commits where we don't want the link to go RESET mode when link_reset() is called. Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Acked-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* tipc: send out RESET immediately when link goes downJon Paul Maloy2015-10-151-0/+12
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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: Jon Maloy <jon.maloy@ericsson.com> Acked-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* tipc: delay ESTABLISH state event when link is establishedJon Paul Maloy2015-10-151-14/+26
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Link establishing, just like link teardown, is a non-atomic action, in the sense that discovering that conditions are right to establish a link, and the actual adding of the link to one of the node's send slots is done in two different lock contexts. The link FSM is designed to help bridging the gap between the two contexts in a safe manner. We have now discovered a weakness in the implementaton of this FSM. Because we directly let the link go from state LINK_ESTABLISHING to state LINK_ESTABLISHED already in the first lock context, we are unable to distinguish between a fully established link, i.e., a link that has been added to its slot, and a link that has not yet reached the second lock context. It may hence happen that a manual intervention, e.g., when disabling an interface, causes the function tipc_node_link_down() to try removing the link from the node slots, decrementing its active link counter etc, although the link was never added there in the first place. We solve this by delaying the actual state change until we reach the second lock context, inside the function tipc_node_link_up(). This makes it possible for potentail callers of __tipc_node_link_down() to know if they should proceed or not, and the problem is solved. Unforunately, the situation described above also has a second problem. Since there by necessity is a tipc_node_link_up() call pending once the node lock has been released, we must defuse that call by setting the link back from LINK_ESTABLISHING to LINK_RESET state. This forces us to make a slight modification to the link FSM, which will now look as follows. +------------------------------------+ |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 | | | | +-------------+ | | | | | | RESET_EVT | | | | | | | | | | | V V V | | | | +-------------+ +--------------+ RESET_EVT| +--->| RESET |--------->| ESTABLISHING |<----------------+ +-------------+ PEER_ +--------------+ | A RESET_EVT | | | | | | | |FAILOVER_ |FAILOVER_ |FAILOVER_ |BEGIN_EVT |END_EVT |BEGIN_EVT | | | V | | +-------------+ | | FAILINGOVER |<----------------+ +-------------+ Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Acked-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* tipc: disallow packet duplicates in link deferred queueJon Paul Maloy2015-10-151-1/+1
| | | | | | | | | | | | | | | | | | | | | After the previous commits, we are guaranteed that no packets of type LINK_PROTOCOL or with illegal sequence numbers will be attempted added to the link deferred queue. This makes it possible to make some simplifications to the sorting algorithm in the function tipc_skb_queue_sorted(). We also alter the function so that it will drop packets if one with the same seqeunce number is already present in the queue. This is necessary because we have identified weird packet sequences, involving duplicate packets, where a legitimate in-sequence packet may advance to the head of the queue without being detected and de-queued. Finally, we make this function outline, since it will now be called only in exceptional cases. Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Acked-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* tipc: improve sequence number checkingJon Paul Maloy2015-10-151-14/+12
| | | | | | | | | | | | | | | | | | | | | | | The sequence number of an incoming packet is currently only checked for less than, equality to, or bigger than the next expected number, meaning that the receive window in practice becomes one half sequence number cycle, or U16_MAX/2. This does not make sense, and may not even be safe if there are extreme delays in the network. Any packet sent by the peer during the ongoing cycle must belong inside his current send window, or should otherwise be dropped if possible. Since a link endpoint cannot know its peer's current send window, it has to base this sanity check on a worst-case assumption, i.e., that the peer is using a maximum sized window of 8191 packets. Using this assumption, we now add a check that the sequence number is not bigger than next_expected + TIPC_MAX_LINK_WIN. We also re-order the checks done, so that the receive window test is performed before the gap test. This way, we are guaranteed that no packet with illegal sequence numbers are ever added to the deferred queue. Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Acked-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* tipc: simplify tipc_link_rcv() reception loopJon Paul Maloy2015-10-151-37/+47
| | | | | | | | | | | | | | | | Currently, all packets received in tipc_link_rcv() are unconditionally added to the packet deferred queue, whereafter that queue is walked and all its buffers evaluated for delivery. This is both non-optimal and and makes the queue sorting function unnecessary complex. This commit changes the loop so that an arrived packet is evaluated first, and added to the deferred queue only when a sequence number gap is discovered. A non-empty deferred queue is walked until it is empty or until its head's sequence number doesn't fit. Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Acked-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* tipc: limit usage of temporary skb list during packet receptionJon Paul Maloy2015-10-151-8/+7
| | | | | | | | | | | | | | | | | | | | | | During packet reception, the function tipc_link_rcv() adds its accepted packets to a temporary buffer queue, before finally splicing this queue into the lock protected input queue that will be delivered up to the socket layer. The purpose is to reduce potential contention on the input queue lock. However, since the vast majority of packets arrive in sequence, they will anyway be added one by one to the input queue, and the use of the temporary queue becomes a sub-optimization. The only case where this queue makes sense is when unpacking buffers from a bundle packet; here we want to avoid dozens of small buffers to be added individually to the lock-protected input queue in a tight loop. In this commit, we remove the general usage of the temporary queue, and keep it only for the packet unbundling case. Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Acked-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* tipc: fix stale link problem during synchronizationJon Paul Maloy2015-08-231-1/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Recent changes to the link synchronization means that we can now just drop packets arriving on the synchronizing link before the synch point is reached. This has lead to significant simplifications to the implementation, but also turns out to have a flip side that we need to consider. Under unlucky circumstances, the two endpoints may end up repeatedly dropping each other's packets, while immediately asking for retransmission of the same packets, just to drop them once more. This pattern will eventually be broken when the synch point is reached on the other link, but before that, the endpoints may have arrived at the retransmission limit (stale counter) that indicates that the link should be broken. We see this happen at rare occasions. The fix for this is to not ask for retransmissions when a link is in state LINK_SYNCHING. The fact that the link has reached this state means that it has already received the first SYNCH packet, and that it knows the synch point. Hence, it doesn't need any more packets until the other link has reached the synch point, whereafter it can go ahead and ask for the missing packets. However, because of the reduced traffic on the synching link that follows this change, it may now take longer to discover that the synch point has been reached. We compensate for this by letting all packets, on any of the links, trig a check for synchronization termination. This is possible because the packets themselves don't contain any information that is needed for discovering this condition. Reviewed-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* tipc: interrupt link synchronization when a link goes downJon Paul Maloy2015-08-231-1/+1
| | | | | | | | | | | | | | | | | | | | When we introduced the new link failover/synch mechanism in commit 6e498158a827fd515b514842e9a06bdf0f75ab86 ("tipc: move link synch and failover to link aggregation level"), we missed the case when the non-tunnel link goes down during the link synchronization period. In this case the tunnel link will remain in state LINK_SYNCHING, something leading to unpredictable behavior when the failover procedure is initiated. In this commit, we ensure that the node and remaining link goes back to regular communication state (SELF_UP_PEER_UP/LINK_ESTABLISHED) when one of the parallel links goes down. We also ensure that we don't re-enter synch mode if subsequent SYNCH packets arrive on the remaining link. Reviewed-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* tipc: clean up link creationJon Paul Maloy2015-07-301-76/+60
| | | | | | | | | | | We simplify the link creation function tipc_link_create() and the way the link struct it is connected to the node struct. In particular, we remove the duplicate initialization of some fields which are anyway set in tipc_link_reset(). Tested-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* tipc: use temporary, non-protected skb queue for bundle receptionJon Paul Maloy2015-07-301-15/+19
| | | | | | | | | | | | | | | | | Currently, when we extract small messages from a message bundle, or when many messages have accumulated in the link arrival queue, those messages are added one by one to the lock protected link input queue. This may increase contention with the reader of that queue, in the function tipc_sk_rcv(). This commit introduces a temporary, unprotected input queue in tipc_link_rcv() for such cases. Only when the arrival queue has been emptied, and the function is ready to return, does it splice the whole temporary queue into the real input queue. Tested-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* tipc: remove implicit message delivery in node_unlock()Jon Paul Maloy2015-07-301-18/+3
| | | | | | | | | | | | | | | | | | After the most recent changes, all access calls to a link which may entail addition of messages to the link's input queue are postpended by an explicit call to tipc_sk_rcv(), using a reference to the correct queue. This means that the potentially hazardous implicit delivery, using tipc_node_unlock() in combination with a binary flag and a cached queue pointer, now has become redundant. This commit removes this implicit delivery mechanism both for regular data messages and for binding table update messages. Tested-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* tipc: make resetting of links non-atomicJon Paul Maloy2015-07-301-1/+1
| | | | | | | | | | | | | | | | | | 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: Ying Xue <ying.xue@windriver.com> Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* tipc: merge link->exec_mode and link->state into one FSMJon Paul Maloy2015-07-301-158/+192
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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: Ying Xue <ying.xue@windriver.com> Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* tipc: move protocol message sending away from link FSMJon Paul Maloy2015-07-301-21/+30
| | | | | | | | | | | | | | | | | | 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: Ying Xue <ying.xue@windriver.com> Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* tipc: move link synch and failover to link aggregation levelJon Paul Maloy2015-07-301-350/+132
| | | | | | | | | | | | | | | 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: Ying Xue <ying.xue@windriver.com> Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* tipc: reverse call order for link_reset()->node_link_down()Jon Paul Maloy2015-07-301-5/+1
| | | | | | | | | | | | | | | | | 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: Ying Xue <ying.xue@windriver.com> Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* tipc: move all link_reset() calls to link aggregation levelJon Paul Maloy2015-07-301-61/+20
| | | | | | | | | | | | | | | | 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: Ying Xue <ying.xue@windriver.com> Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* tipc: eliminate function tipc_link_activate()Jon Paul Maloy2015-07-301-13/+4
| | | | | | | | | | | | | | | | | | | | | | 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: Ying Xue <ying.xue@windriver.com> Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* tipc: fix bug in broadcast synch message create functionJon Maloy2015-07-291-0/+3
| | | | | | | | | | | | | | | | In commit d999297c3dbbe7fdd832f7fa4ec84301e170b3e6 ("tipc: reduce locking scope during packet reception") we introduced a new function tipc_build_bcast_sync_msg(), which carries initial synchronization data between two nodes at first contact and at re-contact. In this function, we missed to add synchronization data, with the effect that the broadcast link endpoints will fail to synchronize correctly at re-contact between a running and a restarted node. All other cases work as intended. With this commit, we fix this bug. Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* tipc: fix compatibility bugJon Paul Maloy2015-07-211-1/+1
| | | | | | | | | | | | | | | | | In commit d999297c3dbbe7fdd832f7fa4ec84301e170b3e6 ("tipc: reduce locking scope during packet reception") we introduced a new function tipc_link_proto_rcv(). This function contains a bug, so that it sometimes by error sends out a non-zero link priority value in created protocol messages. The bug may lead to an extra link reset at initial link establising with older nodes. This will never happen more than once, whereafter the link will work as intended. We fix this bug in this commit. Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* tipc: reduce locking scope during packet receptionJon Paul Maloy2015-07-201-372/+301
| | | | | | | | | | | | | | | | | | | | | | | | | | We convert packet/message reception according to the same principle we have been using for message sending and timeout handling: We move the function tipc_rcv() to node.c, hence handling the initial packet reception at the link aggregation level. The function grabs the node lock, selects the receiving link, and accesses it via a new call tipc_link_rcv(). This function appends buffers to the input queue for delivery upwards, but it may also append outgoing packets to the xmit queue, just as we do during regular message sending. The latter will happen when buffers are forwarded from the link backlog, or when retransmission is requested. Upon return of this function, and after having released the node lock, tipc_rcv() delivers/tranmsits the contents of those queues, but it may also perform actions such as link activation or reset, as indicated by the return flags from the link. This reduces the number of cpu cycles spent inside the node spinlock, and reduces contention on that lock. Reviewed-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* tipc: introduce node contact FSMJon Paul Maloy2015-07-201-42/+32
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The logics for determining when a node is permitted to establish and maintain contact with its peer node becomes non-trivial in the presence of multiple parallel links that may come and go independently. A known failure scenario is that one endpoint registers both its links to the peer lost, cleans up it binding table, and prepares for a table update once contact is re-establihed, while the other endpoint may see its links reset and re-established one by one, hence seeing no need to re-synchronize the binding table. To avoid this, a node must not allow re-establishing contact until it has confirmation that even the peer has lost both links. Currently, the mechanism for handling this consists of setting and resetting two state flags from different locations in the code. This solution is hard to understand and maintain. A closer analysis even reveals that it is not completely safe. In this commit we do instead introduce an FSM that keeps track of the conditions for when the node can establish and maintain links. It has six states and four events, and is strictly based on explicit knowledge about the own node's and the peer node's contact states. Only events leading to state change are shown as edges in the figure below. +--------------+ | SELF_UP/ | +---------------->| PEER_COMING |-----------------+ SELF_ | +--------------+ |PEER_ ESTBL_ | | |ESTBL_ CONTACT| SELF_LOST_CONTACT | |CONTACT | v | | +--------------+ | | PEER_ | SELF_DOWN/ | SELF_ | | LOST_ +--| PEER_LEAVING |<--+ LOST_ v +-------------+ CONTACT | +--------------+ | CONTACT +-----------+ | SELF_DOWN/ |<----------+ +----------| SELF_UP/ | | PEER_DOWN |<----------+ +----------| PEER_UP | +-------------+ SELF_ | +--------------+ | PEER_ +-----------+ | LOST_ +--| SELF_LEAVING/|<--+ LOST_ A | CONTACT | PEER_DOWN | CONTACT | | +--------------+ | | A | PEER_ | PEER_LOST_CONTACT | |SELF_ ESTBL_ | | |ESTBL_ CONTACT| +--------------+ |CONTACT +---------------->| PEER_UP/ |-----------------+ | SELF_COMING | +--------------+ Reviewed-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* tipc: move link supervision timer to node levelJon Paul Maloy2015-07-201-74/+4
| | | | | | | | | | | | | | In our effort to move control of the links to the link aggregation layer, we move the perodic link supervision timer to struct tipc_node. The new timer is shared between all links belonging to the node, thus saving resources, while still kicking the FSM on both its pertaining links at each expiration. The current link timer and corresponding functions are removed. Reviewed-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* tipc: simplify link timer implementationJon Paul Maloy2015-07-201-45/+71
| | | | | | | | | | | | | | | We create a second, simpler, link timer function, tipc_link_timeout(). The new function makes use of the new FSM function introduced in the previous commit, and just like it, takes a buffer queue as parameter. It returns an event bit field and potentially a link protocol packet to the caller. The existing timer function, link_timeout(), is still needed for a while, so we redesign it to become a wrapper around the new function. Reviewed-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* tipc: improve link FSM implementationJon Paul Maloy2015-07-201-156/+188
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The link FSM implementation is currently unnecessarily complex. It sometimes checks for conditional state outside the FSM data before deciding next state, and often performs actions directly inside the FSM logics. In this commit, we create a second, simpler FSM implementation, that as far as possible acts only on states and events that it is strictly defined for, and postpone any actions until it is finished with its decisions. It also returns an event flag field and an a buffer queue which may potentially contain a protocol message to be sent by the caller. Unfortunately, we cannot yet make the FSM "clean", in the sense that its decisions are only based on FSM state and event, and that state changes happen only here. That will have to wait until the activate/reset logics has been cleaned up in a future commit. We also rename the link states as follows: WORKING_WORKING -> TIPC_LINK_WORKING WORKING_UNKNOWN -> TIPC_LINK_PROBING RESET_UNKNOWN -> TIPC_LINK_RESETTING RESET_RESET -> TIPC_LINK_ESTABLISHING The existing FSM function, link_state_event(), is still needed for a while, so we redesign it to make use of the new function. Reviewed-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* tipc: introduce new link protocol msg create functionJon Paul Maloy2015-07-201-67/+77
| | | | | | | | | | | | | | As a preparation for later changes, we introduce a new function tipc_link_build_proto_msg(). Instead of actually sending the created protocol message, it only creates it and adds it to the head of a skb queue provided by the caller. Since we still need the existing function tipc_link_protocol_xmit() for a while, we redesign it to make use of the new function. Reviewed-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* tipc: clean up definitions and usage of link flagsJon Paul Maloy2015-07-201-40/+58
| | | | | | | | | | | | | | | | | | | | | | | | | | | The status flag LINK_STOPPED is not needed any more, since the mechanism for delayed deletion of links has been removed. Likewise, LINK_STARTED and LINK_START_EVT are unnecessary, because we can just as well start the link timer directly from inside tipc_link_create(). We eliminate these flags in this commit. Instead of the above flags, we now introduce three new link modes, TIPC_LINK_OPEN, TIPC_LINK_BLOCKED and TIPC_LINK_TUNNEL. The values indicate whether, and in the case of TIPC_LINK_TUNNEL, which, messages the link is allowed to receive in this state. TIPC_LINK_BLOCKED also blocks timer-driven protocol messages to be sent out, and any change to the link FSM. Since the modes are mutually exclusive, we convert them to state values, and rename the 'flags' field in struct tipc_link to 'exec_mode'. Finally, we move the #defines for link FSM states and events from link.h into enums inside the file link.c, which is the real usage scope of these definitions. Reviewed-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* tipc: make media xmit call outside node spinlock contextJon Paul Maloy2015-07-201-60/+72
| | | | | | | | | | | | | | | | | | | | | 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: Ying Xue <ying.xue@windriver.com> Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* tipc: change sk_buffer handling in tipc_link_xmit()Jon Paul Maloy2015-07-201-14/+9
| | | | | | | | | | | | | | | | | | | | When the function tipc_link_xmit() is given a buffer list for transmission, it currently consumes the list both when transmission is successful and when it fails, except for the special case when it encounters link congestion. This behavior is inconsistent, and needs to be corrected if we want to avoid problems in later commits in this series. In this commit, we change this to let the function consume the list only when transmission is successful, and leave the list with the sender in all other cases. We also modifiy the socket code so that it adapts to this change, i.e., purges the list when a non-congestion error code is returned. Reviewed-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* tipc: move link input queue to tipc_nodeJon Paul Maloy2015-07-201-12/+15
| | | | | | | | | | | | | | | | | At present, the link input queue and the name distributor receive queues are fields aggregated in struct tipc_link. This is a hazard, because a link might be deleted while a receiving socket still keeps reference to one of the queues. This commit fixes this bug. However, rather than adding yet another reference counter to the critical data path, we move the two queues to safe ground inside struct tipc_node, which is already protected, and let the link code only handle references to the queues. This is also in line with planned later changes in this area. Reviewed-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* tipc: introduce link entry structure to struct tipc_nodeJon Paul Maloy2015-07-201-28/+32
| | | | | | | | | | | | | | | struct 'tipc_node' currently contains two arrays for link attributes, one for the link pointers, and one for the usable link MTUs. We now group those into a new struct 'tipc_link_entry', and intoduce one single array consisting of such enties. Apart from being a cosmetic improvement, this is a starting point for the strict master-slave relation between node and link that we will introduce in the following commits. Reviewed-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* tipc: purge backlog queue counters when broadcast link is resetJon Paul Maloy2015-06-281-1/+1
| | | | | | | | | | | | | | | | | | | | | | In commit 1f66d161ab3d8b518903fa6c3f9c1f48d6919e74 ("tipc: introduce starvation free send algorithm") we introduced a counter per priority level for buffers in the link backlog queue. We also introduced a new function tipc_link_purge_backlog(), to reset these counters to zero when the link is reset. Unfortunately, we missed to call this function when the broadcast link is reset, with the result that the values of these counters might be permanently skewed when new nodes are attached. This may in the worst case lead to permananent, but spurious, broadcast link congestion, where no broadcast packets can be sent at all. We fix this bug with this commit. Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* tipc: fix bug in link protocol message create functionJon Paul Maloy2015-05-261-2/+0
| | | | | | | | | | | | | | | | | | | In commit dd3f9e70f59f43a5712eba9cf3ee4f1e6999540c ("tipc: add packet sequence number at instant of transmission") we made a change with the consequence that packets in the link backlog queue don't contain valid sequence numbers. However, when we create a link protocol message, we still use the sequence number of the first packet in the backlog, if there is any, as "next_sent" indicator in the message. This may entail unnecessary retransissions or stale packet transmission when there is very low traffic on the link. This commit fixes this issue by only using the current value of tipc_link::snd_nxt as indicator. Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* tipc: add packet sequence number at instant of transmissionJon Paul Maloy2015-05-141-9/+28
| | | | | | | | | | | | | | | | | | | | Currently, the packet sequence number is updated and added to each packet at the moment a packet is added to the link backlog queue. This is wasteful, since it forces the code to traverse the send packet list packet by packet when adding them to the backlog queue. It would be better to just splice the whole packet list into the backlog queue when that is the right action to do. In this commit, we do this change. Also, since the sequence numbers cannot now be assigned to the packets at the moment they are added the backlog queue, we do instead calculate and add them at the moment of transmission, when the backlog queue has to be traversed anyway. We do this in the function tipc_link_push_packet(). Reviewed-by: Erik Hugne <erik.hugne@ericsson.com> Reviewed-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* tipc: improve link congestion algorithmJon Paul Maloy2015-05-141-5/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The link congestion algorithm used until now implies two problems. - It is too generous towards lower-level messages in situations of high load by giving "absolute" bandwidth guarantees to the different priority levels. LOW traffic is guaranteed 10%, MEDIUM is guaranted 20%, HIGH is guaranteed 30%, and CRITICAL is guaranteed 40% of the available bandwidth. But, in the absence of higher level traffic, the ratio between two distinct levels becomes unreasonable. E.g. if there is only LOW and MEDIUM traffic on a system, the former is guaranteed 1/3 of the bandwidth, and the latter 2/3. This again means that if there is e.g. one LOW user and 10 MEDIUM users, the former will have 33.3% of the bandwidth, and the others will have to compete for the remainder, i.e. each will end up with 6.7% of the capacity. - Packets of type MSG_BUNDLER are created at SYSTEM importance level, but only after the packets bundled into it have passed the congestion test for their own respective levels. Since bundled packets don't result in incrementing the level counter for their own importance, only occasionally for the SYSTEM level counter, they do in practice obtain SYSTEM level importance. Hence, the current implementation provides a gap in the congestion algorithm that in the worst case may lead to a link reset. We now refine the congestion algorithm as follows: - A message is accepted to the link backlog only if its own level counter, and all superior level counters, permit it. - The importance of a created bundle packet is set according to its contents. A bundle packet created from messges at levels LOW to CRITICAL is given importance level CRITICAL, while a bundle created from a SYSTEM level message is given importance SYSTEM. In the latter case only subsequent SYSTEM level messages are allowed to be bundled into it. This solves the first problem described above, by making the bandwidth guarantee relative to the total number of users at all levels; only the upper limit for each level remains absolute. In the example described above, the single LOW user would use 1/11th of the bandwidth, the same as each of the ten MEDIUM users, but he still has the same guarantee against starvation as the latter ones. The fix also solves the second problem. If the CRITICAL level is filled up by bundle packets of that level, no lower level packets will be accepted any more. Suggested-by: Gergely Kiss <gergely.kiss@ericsson.com> Reviewed-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* tipc: simplify link supervision checkpointingJon Paul Maloy2015-05-141-59/+22
| | | | | | | | | | | | | | | | | | | | | We change the sequence number checkpointing that is performed by the timer in order to discover if the peer is active. Currently, we store a checkpoint of the next expected sequence number "rcv_nxt" at each timer expiration, and compare it to the current expected number at next timeout expiration. Instead, we now use the already existing field "silent_intv_cnt" for this task. We step the counter at each timeout expiration, and zero it at each valid received packet. If no valid packet has been received from the peer after "abort_limit" number of silent timer intervals, the link is declared faulty and reset. We also remove the multiple instances of timer activation from inside the FSM function "link_state_event()", and now do it at only one place; at the end of the timer function itself. Reviewed-by: Erik Hugne <erik.hugne@ericsson.com> Reviewed-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* tipc: rename fields in struct tipc_linkJon Paul Maloy2015-05-141-77/+78
| | | | | | | | | | | | | | | | | | We rename some fields in struct tipc_link, in order to give them more descriptive names: next_in_no -> rcv_nxt next_out_no-> snd_nxt fsm_msg_cnt-> silent_intv_cnt cont_intv -> keepalive_intv last_retransmitted -> last_retransm There are no functional changes in this commit. Reviewed-by: Erik Hugne <erik.hugne@ericsson.com> Reviewed-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* tipc: simplify packet sequence number handlingJon Paul Maloy2015-05-141-19/+18
| | | | | | | | | | | | | | | | | | | Although the sequence number in the TIPC protocol is 16 bits, we have until now stored it internally as an unsigned 32 bits integer. We got around this by always doing explicit modulo-65535 operations whenever we need to access a sequence number. We now make the incoming and outgoing sequence numbers to unsigned 16-bit integers, and remove the modulo operations where applicable. We also move the arithmetic inline functions for 16 bit integers to core.h, and the function buf_seqno() to msg.h, so they can easily be accessed from anywhere in the code. Reviewed-by: Erik Hugne <erik.hugne@ericsson.com> Reviewed-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* tipc: simplify link timer handlingJon Paul Maloy2015-05-141-3/+3
| | | | | | | | | | | | | | | | | | | | | | Prior to this commit, the link timer has been running at a "continuity interval" of configured link tolerance/4. When a timer wakes up and discovers that there has been no sign of life from the peer during the previous interval, it divides its own timer interval by another factor four, and starts sending one probe per new interval. When the configured link tolerance time has passed without answer, i.e. after 16 unacked probes, the link is declared faulty and reset. This is unnecessary complex. It is sufficient to continue with the original continuity interval, and instead reset the link after four missed probe responses. This makes the timer handling in the link simpler, and opens up for some planned later changes in this area. This commit implements this change. Reviewed-by: Richard Alpe <richard.alpe@ericsson.com> Reviewed-by: Erik Hugne <erik.hugne@ericsson.com> Reviewed-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* tipc: simplify resetting and disabling of bearersJon Paul Maloy2015-05-141-19/+1
| | | | | | | | | | | | | | | | | | | Since commit 4b475e3f2f8e4e241de101c8240f1d74d0470494 ("tipc: eliminate delayed link deletion at link failover") the extra boolean parameter "shutting_down" is not any longer needed for the functions bearer_disable() and tipc_link_delete_list(). Furhermore, the function tipc_link_reset_links(), called from bearer_reset() is now unnecessary. We can just as well delete all the links, as we do in bearer_disable(), and start over with creating new links. This commit introduces those changes. Reviewed-by: Erik Hugne <erik.hugne@ericsson.com> Reviewed-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* tipc: add broadcast link window set/get to nl apiRichard Alpe2015-05-091-30/+36
| | | | | | | | | | | | | | Add the ability to get or set the broadcast link window through the new netlink API. The functionality was unintentionally missing from the new netlink API. Adding this means that we also fix the breakage in the old API when coming through the compat layer. Fixes: 37e2d4843f9e (tipc: convert legacy nl link prop set to nl compat) Reported-by: Tomi Ollila <tomi.ollila@iki.fi> Signed-off-by: Richard Alpe <richard.alpe@ericsson.com> Reviewed-by: Erik Hugne <erik.hugne@ericsson.com> Reviewed-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* tipc: fix problem with parallel link synchronization mechanismJon Paul Maloy2015-04-291-5/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | Currently, we try to accumulate arrived packets in the links's 'deferred' queue during the parallel link syncronization phase. This entails two problems: - With an unlucky combination of arriving packets the algorithm may go into a lockstep with the out-of-sequence handling function, where the synch mechanism is adding a packet to the deferred queue, while the out-of-sequence handling is retrieving it again, thus ending up in a loop inside the node_lock scope. - Even if this is avoided, the link will very often send out unnecessary protocol messages, in the worst case leading to redundant retransmissions. We fix this by just dropping arriving packets on the upcoming link during the synchronization phase, thus relying on the retransmission protocol to resolve the situation once the two links have arrived to a synchronized state. Reviewed-by: Erik Hugne <erik.hugne@ericsson.com> Reviewed-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* tipc: remove wrong use of NLM_F_MULTINicolas Dichtel2015-04-291-4/+4
| | | | | | | | | | | | | | | | | NLM_F_MULTI must be used only when a NLMSG_DONE message is sent. In fact, it is sent only at the end of a dump. Libraries like libnl will wait forever for NLMSG_DONE. Fixes: 35b9dd7607f0 ("tipc: add bearer get/dump to new netlink api") Fixes: 7be57fc69184 ("tipc: add link get/dump to new netlink api") Fixes: 46f15c6794fb ("tipc: add media get/dump to new netlink api") CC: Richard Alpe <richard.alpe@ericsson.com> CC: Jon Maloy <jon.maloy@ericsson.com> CC: Ying Xue <ying.xue@windriver.com> CC: tipc-discussion@lists.sourceforge.net Signed-off-by: Nicolas Dichtel <nicolas.dichtel@6wind.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* tipc: fix node refcount issueErik Hugne2015-04-231-1/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When link statistics is dumped over netlink, we iterate over the list of peer nodes and append each links statistics to the netlink msg. In the case where the dump is resumed after filling up a nlmsg, the node refcnt is decremented without having been incremented previously which may cause the node reference to be freed. When this happens, the following info/stacktrace will be generated, followed by a crash or undefined behavior. We fix this by removing the erroneous call to tipc_node_put inside the loop that iterates over nodes. [ 384.312303] INFO: trying to register non-static key. [ 384.313110] the code is fine but needs lockdep annotation. [ 384.313290] turning off the locking correctness validator. [ 384.313290] CPU: 1 PID: 0 Comm: swapper/1 Not tainted 4.0.0+ #13 [ 384.313290] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011 [ 384.313290] ffff88003c6d0290 ffff88003cc03ca8 ffffffff8170adf1 0000000000000007 [ 384.313290] ffffffff82728730 ffff88003cc03d38 ffffffff810a6a6d 00000000001d7200 [ 384.313290] ffff88003c6d0ab0 ffff88003cc03ce8 0000000000000285 0000000000000001 [ 384.313290] Call Trace: [ 384.313290] <IRQ> [<ffffffff8170adf1>] dump_stack+0x4c/0x65 [ 384.313290] [<ffffffff810a6a6d>] __lock_acquire+0xf3d/0xf50 [ 384.313290] [<ffffffff810a7375>] lock_acquire+0xd5/0x290 [ 384.313290] [<ffffffffa0043e8c>] ? link_timeout+0x1c/0x170 [tipc] [ 384.313290] [<ffffffffa0043e70>] ? link_state_event+0x4e0/0x4e0 [tipc] [ 384.313290] [<ffffffff81712890>] _raw_spin_lock_bh+0x40/0x80 [ 384.313290] [<ffffffffa0043e8c>] ? link_timeout+0x1c/0x170 [tipc] [ 384.313290] [<ffffffffa0043e8c>] link_timeout+0x1c/0x170 [tipc] [ 384.313290] [<ffffffff810c4698>] call_timer_fn+0xb8/0x490 [ 384.313290] [<ffffffff810c45e0>] ? process_timeout+0x10/0x10 [ 384.313290] [<ffffffff810c5a2c>] run_timer_softirq+0x21c/0x420 [ 384.313290] [<ffffffffa0043e70>] ? link_state_event+0x4e0/0x4e0 [tipc] [ 384.313290] [<ffffffff8105a954>] __do_softirq+0xf4/0x630 [ 384.313290] [<ffffffff8105afdd>] irq_exit+0x5d/0x60 [ 384.313290] [<ffffffff8103ade1>] smp_apic_timer_interrupt+0x41/0x50 [ 384.313290] [<ffffffff817144a0>] apic_timer_interrupt+0x70/0x80 [ 384.313290] <EOI> [<ffffffff8100db10>] ? default_idle+0x20/0x210 [ 384.313290] [<ffffffff8100db0e>] ? default_idle+0x1e/0x210 [ 384.313290] [<ffffffff8100e61a>] arch_cpu_idle+0xa/0x10 [ 384.313290] [<ffffffff81099803>] cpu_startup_entry+0x2c3/0x530 [ 384.313290] [<ffffffff810d2893>] ? clockevents_register_device+0x113/0x200 [ 384.313290] [<ffffffff81038b0f>] start_secondary+0x13f/0x170 Fixes: 8a0f6ebe8494 ("tipc: involve reference counter for node structure") Signed-off-by: Erik Hugne <erik.hugne@ericsson.com> Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* tipc: simplify link mtu negotiationJon Paul Maloy2015-04-021-97/+32
| | | | | | | | | | | | | | | | | | | | | | | | When a link is being established, the two endpoints advertise their respective interface MTU in the transmitted RESET and ACTIVATE messages. If there is any difference, the lower of the two MTUs will be selected for use by both endpoints. However, as a remnant of earlier attempts to introduce TIPC level routing. there also exists an MTU discovery mechanism. If an intermediate node has a lower MTU than the two endpoints, they will discover this through a bisectional approach, and finally adopt this MTU for common use. Since there is no TIPC level routing, and probably never will be, this mechanism doesn't make any sense, and only serves to make the link level protocol unecessarily complex. In this commit, we eliminate the MTU discovery algorithm,and fall back to the simple MTU advertising approach. This change is fully backwards compatible. Reviewed-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* tipc: eliminate delayed link deletion at link failoverJon Paul Maloy2015-04-021-68/+56
| | | | | | | | | | | | | | | | | | | | | | | | | When a bearer is disabled manually, all its links have to be reset and deleted. However, if there is a remaining, parallel link ready to take over a deleted link's traffic, we currently delay the delete of the removed link until the failover procedure is finished. This is because the remaining link needs to access state from the reset link, such as the last received packet number, and any partially reassembled buffer, in order to perform a successful failover. In this commit, we do instead move the state data over to the new link, so that it can fulfill the procedure autonomously, without accessing any data on the old link. This means that we can now proceed and delete all pertaining links immediately when a bearer is disabled. This saves us from some unnecessary complexity in such situations. We also choose to change the confusing definitions CHANGEOVER_PROTOCOL, ORIGINAL_MSG and DUPLICATE_MSG to the more descriptive TUNNEL_PROTOCOL, FAILOVER_MSG and SYNCH_MSG respectively. Reviewed-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* tipc: drop tunneled packet duplicates at receptionJon Paul Maloy2015-04-021-85/+47
| | | | | | | | | | | | | | | | | | | | | | | | | | | | In commit 8b4ed8634f8b3f9aacfc42b4a872d30c36b9e255 ("tipc: eliminate race condition at dual link establishment") we introduced a parallel link synchronization mechanism that guarentees sequential delivery even for users switching from an old to a newly established link. The new mechanism makes it unnecessary to deliver the tunneled duplicate packets back to the old link, as we are currently doing. It is now sufficient to use the last tunneled packet's inner sequence number as synchronization point between the two parallel links, whereafter it can be dropped. In this commit, we drop the duplicate packets arriving on the new link, after updating the synchronization point at each new arrival. Although it would now have been sufficient for the other endpoint to only tunnel the last packet in its send queue, and not the entire queue, we must still do this to maintain compatibility with older nodes. This commit makes it possible to get rid if some complex interaction between the two parallel links. Reviewed-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* tipc: involve reference counter for node structureYing Xue2015-03-291-2/+5
| | | | | | | | | | | | | | | | | | | | | TIPC node hash node table is protected with rcu lock on read side. tipc_node_find() is used to look for a node object with node address through iterating the hash node table. As the entire process of what tipc_node_find() traverses the table is guarded with rcu read lock, it's safe for us. However, when callers use the node object returned by tipc_node_find(), there is no rcu read lock applied. Therefore, this is absolutely unsafe for callers of tipc_node_find(). Now we introduce a reference counter for node structure. Before tipc_node_find() returns node object to its caller, it first increases the reference counter. Accordingly, after its caller used it up, it decreases the counter again. This can prevent a node being used by one thread from being freed by another thread. Reviewed-by: Erik Hugne <erik.hugne@ericsson.com> Reviewed-by: Jon Maloy <jon.maloy@ericson.com> Signed-off-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* tipc: fix potential deadlock when all links are resetYing Xue2015-03-291-4/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | [ 60.988363] ====================================================== [ 60.988754] [ INFO: possible circular locking dependency detected ] [ 60.989152] 3.19.0+ #194 Not tainted [ 60.989377] ------------------------------------------------------- [ 60.989781] swapper/3/0 is trying to acquire lock: [ 60.990079] (&(&n_ptr->lock)->rlock){+.-...}, at: [<ffffffffa0006dca>] tipc_link_retransmit+0x1aa/0x240 [tipc] [ 60.990743] [ 60.990743] but task is already holding lock: [ 60.991106] (&(&bclink->lock)->rlock){+.-...}, at: [<ffffffffa00004be>] tipc_bclink_lock+0x8e/0xa0 [tipc] [ 60.991738] [ 60.991738] which lock already depends on the new lock. [ 60.991738] [ 60.992174] [ 60.992174] the existing dependency chain (in reverse order) is: [ 60.992174] -> #1 (&(&bclink->lock)->rlock){+.-...}: [ 60.992174] [<ffffffff810a9c0c>] lock_acquire+0x9c/0x140 [ 60.992174] [<ffffffff8179c41f>] _raw_spin_lock_bh+0x3f/0x50 [ 60.992174] [<ffffffffa00004be>] tipc_bclink_lock+0x8e/0xa0 [tipc] [ 60.992174] [<ffffffffa0000f57>] tipc_bclink_add_node+0x97/0xf0 [tipc] [ 60.992174] [<ffffffffa0011815>] tipc_node_link_up+0xf5/0x110 [tipc] [ 60.992174] [<ffffffffa0007783>] link_state_event+0x2b3/0x4f0 [tipc] [ 60.992174] [<ffffffffa00193c0>] tipc_link_proto_rcv+0x24c/0x418 [tipc] [ 60.992174] [<ffffffffa0008857>] tipc_rcv+0x827/0xac0 [tipc] [ 60.992174] [<ffffffffa0002ca3>] tipc_l2_rcv_msg+0x73/0xd0 [tipc] [ 60.992174] [<ffffffff81646e66>] __netif_receive_skb_core+0x746/0x980 [ 60.992174] [<ffffffff816470c1>] __netif_receive_skb+0x21/0x70 [ 60.992174] [<ffffffff81647295>] netif_receive_skb_internal+0x35/0x130 [ 60.992174] [<ffffffff81648218>] napi_gro_receive+0x158/0x1d0 [ 60.992174] [<ffffffff81559e05>] e1000_clean_rx_irq+0x155/0x490 [ 60.992174] [<ffffffff8155c1b7>] e1000_clean+0x267/0x990 [ 60.992174] [<ffffffff81647b60>] net_rx_action+0x150/0x360 [ 60.992174] [<ffffffff8105ec43>] __do_softirq+0x123/0x360 [ 60.992174] [<ffffffff8105f12e>] irq_exit+0x8e/0xb0 [ 60.992174] [<ffffffff8179f9f5>] do_IRQ+0x65/0x110 [ 60.992174] [<ffffffff8179da6f>] ret_from_intr+0x0/0x13 [ 60.992174] [<ffffffff8100de9f>] arch_cpu_idle+0xf/0x20 [ 60.992174] [<ffffffff8109dfa6>] cpu_startup_entry+0x2f6/0x3f0 [ 60.992174] [<ffffffff81033cda>] start_secondary+0x13a/0x150 [ 60.992174] -> #0 (&(&n_ptr->lock)->rlock){+.-...}: [ 60.992174] [<ffffffff810a8f7d>] __lock_acquire+0x163d/0x1ca0 [ 60.992174] [<ffffffff810a9c0c>] lock_acquire+0x9c/0x140 [ 60.992174] [<ffffffff8179c41f>] _raw_spin_lock_bh+0x3f/0x50 [ 60.992174] [<ffffffffa0006dca>] tipc_link_retransmit+0x1aa/0x240 [tipc] [ 60.992174] [<ffffffffa0001e11>] tipc_bclink_rcv+0x611/0x640 [tipc] [ 60.992174] [<ffffffffa0008646>] tipc_rcv+0x616/0xac0 [tipc] [ 60.992174] [<ffffffffa0002ca3>] tipc_l2_rcv_msg+0x73/0xd0 [tipc] [ 60.992174] [<ffffffff81646e66>] __netif_receive_skb_core+0x746/0x980 [ 60.992174] [<ffffffff816470c1>] __netif_receive_skb+0x21/0x70 [ 60.992174] [<ffffffff81647295>] netif_receive_skb_internal+0x35/0x130 [ 60.992174] [<ffffffff81648218>] napi_gro_receive+0x158/0x1d0 [ 60.992174] [<ffffffff81559e05>] e1000_clean_rx_irq+0x155/0x490 [ 60.992174] [<ffffffff8155c1b7>] e1000_clean+0x267/0x990 [ 60.992174] [<ffffffff81647b60>] net_rx_action+0x150/0x360 [ 60.992174] [<ffffffff8105ec43>] __do_softirq+0x123/0x360 [ 60.992174] [<ffffffff8105f12e>] irq_exit+0x8e/0xb0 [ 60.992174] [<ffffffff8179f9f5>] do_IRQ+0x65/0x110 [ 60.992174] [<ffffffff8179da6f>] ret_from_intr+0x0/0x13 [ 60.992174] [<ffffffff8100de9f>] arch_cpu_idle+0xf/0x20 [ 60.992174] [<ffffffff8109dfa6>] cpu_startup_entry+0x2f6/0x3f0 [ 60.992174] [<ffffffff81033cda>] start_secondary+0x13a/0x150 [ 60.992174] [ 60.992174] other info that might help us debug this: [ 60.992174] [ 60.992174] Possible unsafe locking scenario: [ 60.992174] [ 60.992174] CPU0 CPU1 [ 60.992174] ---- ---- [ 60.992174] lock(&(&bclink->lock)->rlock); [ 60.992174] lock(&(&n_ptr->lock)->rlock); [ 60.992174] lock(&(&bclink->lock)->rlock); [ 60.992174] lock(&(&n_ptr->lock)->rlock); [ 60.992174] [ 60.992174] *** DEADLOCK *** [ 60.992174] [ 60.992174] 3 locks held by swapper/3/0: [ 60.992174] #0: (rcu_read_lock){......}, at: [<ffffffff81646791>] __netif_receive_skb_core+0x71/0x980 [ 60.992174] #1: (rcu_read_lock){......}, at: [<ffffffffa0002c35>] tipc_l2_rcv_msg+0x5/0xd0 [tipc] [ 60.992174] #2: (&(&bclink->lock)->rlock){+.-...}, at: [<ffffffffa00004be>] tipc_bclink_lock+0x8e/0xa0 [tipc] [ 60.992174] The correct the sequence of grabbing n_ptr->lock and bclink->lock should be that the former is first held and the latter is then taken, which exactly happened on CPU1. But especially when the retransmission of broadcast link is failed, bclink->lock is first held in tipc_bclink_rcv(), and n_ptr->lock is taken in link_retransmit_failure() called by tipc_link_retransmit() subsequently, which is demonstrated on CPU0. As a result, deadlock occurs. If the order of holding the two locks happening on CPU0 is reversed, the deadlock risk will be relieved. Therefore, the node lock taken in link_retransmit_failure() originally is moved to tipc_bclink_rcv() so that it's obtained before bclink lock. But the precondition of the adjustment of node lock is that responding to bclink reset event must be moved from tipc_bclink_unlock() to tipc_node_unlock(). Reviewed-by: Erik Hugne <erik.hugne@ericsson.com> Signed-off-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: David S. Miller <davem@davemloft.net>
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