linux/net/tipc/node.h, branch v4.0

tipc: convert legacy nl node dump to nl compat

2015-02-09T21:20:49Z

Convert TIPC_CMD_GET_NODES to compat dumpit and remove global node counter solely used by the legacy API. Signed-off-by: Richard Alpe Reviewed-by: Erik Hugne Reviewed-by: Ying Xue Reviewed-by: Jon Maloy Signed-off-by: David S. Miller

tipc: convert legacy nl link dump to nl compat

2015-02-09T21:20:48Z

Convert TIPC_CMD_GET_LINKS to compat dumpit and remove global link counter solely used by the legacy API. Signed-off-by: Richard Alpe Reviewed-by: Erik Hugne Reviewed-by: Ying Xue Reviewed-by: Jon Maloy Signed-off-by: David S. Miller

tipc: eliminate race condition at multicast reception

2015-02-06T00:00:03Z

In a previous commit in this series we resolved a race problem during unicast message reception. Here, we resolve the same problem at multicast reception. We apply the same technique: an input queue serializing the delivery of arriving buffers. The main difference is that here we do it in two steps. First, the broadcast link feeds arriving buffers into the tail of an arrival queue, which head is consumed at the socket level, and where destination lookup is performed. Second, if the lookup is successful, the resulting buffer clones are fed into a second queue, the input queue. This queue is consumed at reception in the socket just like in the unicast case. Both queues are protected by the same lock, -the one of the input queue. Reviewed-by: Ying Xue Signed-off-by: Jon Maloy Signed-off-by: David S. Miller

tipc: resolve race problem at unicast message reception

2015-02-06T00:00:02Z

TIPC handles message cardinality and sequencing at the link layer, before passing messages upwards to the destination sockets. During the upcall from link to socket no locks are held. It is therefore possible, and we see it happen occasionally, that messages arriving in different threads and delivered in sequence still bypass each other before they reach the destination socket. This must not happen, since it violates the sequentiality guarantee. We solve this by adding a new input buffer queue to the link structure. Arriving messages are added safely to the tail of that queue by the link, while the head of the queue is consumed, also safely, by the receiving socket. Sequentiality is secured per socket by only allowing buffers to be dequeued inside the socket lock. Since there may be multiple simultaneous readers of the queue, we use a 'filter' parameter to reduce the risk that they peek the same buffer from the queue, hence also reducing the risk of contention on the receiving socket locks. This solves the sequentiality problem, and seems to cause no measurable performance degradation. A nice side effect of this change is that lock handling in the functions tipc_rcv() and tipc_bcast_rcv() now becomes uniform, something that will enable future simplifications of those functions. Reviewed-by: Ying Xue Signed-off-by: Jon Maloy Signed-off-by: David S. Miller

tipc: make tipc node table aware of net namespace

2015-01-12T21:24:32Z

Global variables associated with node table are below: - node table list (node_htable) - node hash table list (tipc_node_list) - node table lock (node_list_lock) - node number counter (tipc_num_nodes) - node link number counter (tipc_num_links) To make node table support namespace, above global variables must be moved to tipc_net structure in order to keep secret for different namespaces. As a consequence, these variables are allocated and initialized when namespace is created, and deallocated when namespace is destroyed. After the change, functions associated with these variables have to utilize a namespace pointer to access them. So adding namespace pointer as a parameter of these functions is the major change made in the commit. Signed-off-by: Ying Xue Tested-by: Tero Aho Reviewed-by: Jon Maloy Signed-off-by: David S. Miller

tipc: use generic SKB list APIs to manage deferred queue of link

2014-11-26T17:30:17Z

Use standard SKB list APIs associated with struct sk_buff_head to manage link's deferred queue, simplifying relevant code. Signed-off-by: Ying Xue Reviewed-by: Jon Maloy Signed-off-by: David S. Miller

tipc: remove node subscription infrastructure

2014-11-26T17:30:16Z

The node subscribe infrastructure represents a virtual base class, so its users, such as struct tipc_port and struct publication, can derive its implemented functionalities. However, after the removal of struct tipc_port, struct publication is left as its only single user now. So defining an abstract infrastructure for one user becomes no longer reasonable. If corresponding new functions associated with the infrastructure are moved to name_table.c file, the node subscription infrastructure can be removed as well. Signed-off-by: Ying Xue Reviewed-by: Jon Maloy Signed-off-by: David S. Miller

tipc: add node get/dump to new netlink api

2014-11-21T20:01:31Z

Add TIPC_NL_NODE_GET to the new tipc netlink API. This command can dump the address and node status of all nodes in the tipc cluster. Netlink logical layout of returned node/address data: -> node -> address -> up flag Signed-off-by: Richard Alpe Reviewed-by: Erik Hugne Reviewed-by: Jon Maloy Acked-by: Ying Xue Signed-off-by: David S. Miller

tipc: fix a potential deadlock

2014-10-21T19:28:15Z

Locking dependency detected below possible unsafe locking scenario: CPU0 CPU1 T0: tipc_named_rcv() tipc_rcv() T1: [grab nametble write lock]* [grab node lock]* T2: tipc_update_nametbl() tipc_node_link_up() T3: tipc_nodesub_subscribe() tipc_nametbl_publish() T4: [grab node lock]* [grab nametble write lock]* The opposite order of holding nametbl write lock and node lock on above two different paths may result in a deadlock. If we move the the updating of the name table after link state named out of node lock, the reverse order of holding locks will be eliminated, and as a result, the deadlock risk. Signed-off-by: Ying Xue Signed-off-by: Jon Maloy Signed-off-by: David S. Miller

tipc: fix bug in multicast congestion handling

2014-10-07T18:50:15Z

One aim of commit 50100a5e39461b2a61d6040e73c384766c29975d ("tipc: use pseudo message to wake up sockets after link congestion") was to handle link congestion abatement in a uniform way for both unicast and multicast transmit. However, the latter doesn't work correctly, and has been broken since the referenced commit was applied. If a user now sends a burst of multicast messages that is big enough to cause broadcast link congestion, it will be put to sleep, and not be waked up when the congestion abates as it should be. This has two reasons. First, the flag that is used, TIPC_WAKEUP_USERS, is set correctly, but in the wrong field. Instead of setting it in the 'action_flags' field of the arrival node struct, it is by mistake set in the dummy node struct that is owned by the broadcast link, where it will never tested for. Second, we cannot use the same flag for waking up unicast and multicast users, since the function tipc_node_unlock() needs to pick the wakeup pseudo messages to deliver from different queues. It must hence be able to distinguish between the two cases. This commit solves this problem by adding a new flag TIPC_WAKEUP_BCAST_USERS, and a new function tipc_bclink_wakeup_user(). The latter is to be called by tipc_node_unlock() when the named flag, now set in the correct field, is encountered. v2: using explicit 'unsigned int' declaration instead of 'uint', as per comment from David Miller. Signed-off-by: Jon Maloy Signed-off-by: David S. Miller