kernel.git/net/tipc/link.h, branch linux-3.18.y

tipc: use pseudo message to wake up sockets after link congestion

2014-08-23T18:18:33Z

The current link implementation keeps a linked list of blocked ports/ sockets that is populated when there is link congestion. The purpose of this is to let the link know which users to wake up when the congestion abates. This adds unnecessary complexity to the data structure and the code, since it forces us to involve the link each time we want to delete a socket. It also forces us to grab the spinlock port_lock within the scope of node_lock. We want to get rid of this direct dependence, as well as the deadlock hazard resulting from the usage of port_lock. In this commit, we instead let the link keep list of a "wakeup" pseudo messages for use in such situations. Those messages are sent to the pending sockets via the ordinary message reception path, and wake up the socket's owner when they are received. This enables us to get rid of the 'waiting_ports' linked lists in struct tipc_port that manifest this direct reference. As a consequence, we can eliminate another BH entry into the socket, and hence the need to grab port_lock. This is a further step in our effort to remove port_lock altogether. Signed-off-by: Jon Maloy Reviewed-by: Erik Hugne Reviewed-by: Ying Xue Signed-off-by: David S. Miller

tipc: rename temporarily named functions

2014-07-17T04:38:19Z

After the previous commit, we can now give the functions with temporary names, such as tipc_link_xmit2(), tipc_msg_build2() etc., their proper names. There are no functional changes in this commit. Signed-off-by: Jon Maloy Reviewed-by: Erik Hugne Reviewed-by: Ying Xue Signed-off-by: David S. Miller

tipc: remove unreferenced functions

2014-07-17T04:38:19Z

We can now remove a number of functions which have become obsolete and unreferenced through this commit series. There are no functional changes in this commit. Signed-off-by: Jon Maloy Reviewed-by: Erik Hugne Reviewed-by: Ying Xue Signed-off-by: David S. Miller

tipc: make name table distributor use new send function

2014-07-17T04:38:18Z

In a previous commit series ("tipc: new unicast transmission code") we introduced a new message sending function, tipc_link_xmit2(), and moved the unicast data users over to use that function. We now let the internal name table distributor do the same. The interaction between the name distributor and the node/link layer also becomes significantly simpler, so we can eliminate the function tipc_link_names_xmit(). Signed-off-by: Jon Maloy Reviewed-by: Erik Hugne Reviewed-by: Ying Xue Signed-off-by: David S. Miller

tipc: introduce send functions for chained buffers in link

2014-06-27T19:50:54Z

The current link implementation provides several different transmit functions, depending on the characteristics of the message to be sent: if it is an iovec or an sk_buff, if it needs fragmentation or not, if the caller holds the node_lock or not. The permutation of these options gives us an unwanted amount of unnecessarily complex code. As a first step towards simplifying the send path for all messages, we introduce two new send functions at link level, tipc_link_xmit2() and __tipc_link_xmit2(). The former looks up a link to the message destination, and if one is found, it grabs the node lock and calls the second function, which works exclusively inside the node lock protection. If no link is found, and the destination is on the same node, it delivers the message directly to the local destination socket. The new functions take a buffer chain where all packet headers are already prepared, and the correct MTU has been used. These two functions will later replace all other link-level transmit functions. The functions are not backwards compatible, so we have added them as new functions with temporary names. They are tested, but have no users yet. Those will be added later in this series. Signed-off-by: Jon Maloy Reviewed-by: Erik Hugne Reviewed-by: Ying Xue Signed-off-by: David S. Miller

tipc: rename and move message reassembly function

2014-05-14T19:19:48Z

The function tipc_link_frag_rcv() is in reality a re-entrant generic message reassemby function that has nothing in particular to do with the link, where it is defined now. This becomes obvious when we see the need to call the function from other places in the code. In this commit rename it to tipc_buf_append() and move it to the file msg.c. We also simplify its signature by moving the tail pointer to the control block of the head buffer, hence making the head buffer self-contained. Signed-off-by: Jon Maloy Reviewed-by: Ying Xue Signed-off-by: David S. Miller

tipc: avoid to asynchronously reset all links

2014-05-05T21:26:45Z

Postpone the actions of resetting all links until after bclink lock is released, avoiding to asynchronously reset all links. Signed-off-by: Ying Xue Reviewed-by: Erik Hugne Reviewed-by: Jon Maloy Signed-off-by: David S. Miller

tipc: decouple the relationship between bearer and link

2014-04-23T01:17:53Z

Currently on both paths of message transmission and reception, the read lock of tipc_net_lock must be held before bearer is accessed, while the write lock of tipc_net_lock has to be taken before bearer is configured. Although it can ensure that bearer is always valid on the two data paths, link and bearer is closely bound together. So as the part of effort of removing tipc_net_lock, the locking policy of bearer protection will be adjusted as below: on the two data paths, RCU is used, and on the configuration path of bearer, RTNL lock is applied. Now RCU just covers the path of message reception. To make it possible to protect the path of message transmission with RCU, link should not use its stored bearer pointer to access bearer, but it should use the bearer identity of its attached bearer as index to get bearer instance from bearer_list array, which can help us decouple the relationship between bearer and link. As a result, bearer on the path of message transmission can be safely protected by RCU when we access bearer_list array within RCU lock protection. Signed-off-by: Ying Xue Reviewed-by: Jon Maloy Reviewed-by: Erik Hugne Tested-by: Erik Hugne Signed-off-by: David S. Miller

tipc: align tipc function names with common naming practice in the network

2014-02-18T22:31:59Z

Rename the following functions, which are shorter and more in line with common naming practice in the network subsystem. tipc_bclink_send_msg->tipc_bclink_xmit tipc_bclink_recv_pkt->tipc_bclink_rcv tipc_disc_recv_msg->tipc_disc_rcv tipc_link_send_proto_msg->tipc_link_proto_xmit link_recv_proto_msg->tipc_link_proto_rcv link_send_sections_long->tipc_link_iovec_long_xmit tipc_link_send_sections_fast->tipc_link_iovec_xmit_fast tipc_link_send_sync->tipc_link_sync_xmit tipc_link_recv_sync->tipc_link_sync_rcv tipc_link_send_buf->__tipc_link_xmit tipc_link_send->tipc_link_xmit tipc_link_send_names->tipc_link_names_xmit tipc_named_recv->tipc_named_rcv tipc_link_recv_bundle->tipc_link_bundle_rcv tipc_link_dup_send_queue->tipc_link_dup_queue_xmit link_send_long_buf->tipc_link_frag_xmit tipc_multicast->tipc_port_mcast_xmit tipc_port_recv_mcast->tipc_port_mcast_rcv tipc_port_reject_sections->tipc_port_iovec_reject tipc_port_recv_proto_msg->tipc_port_proto_rcv tipc_connect->tipc_port_connect __tipc_connect->__tipc_port_connect __tipc_disconnect->__tipc_port_disconnect tipc_disconnect->tipc_port_disconnect tipc_shutdown->tipc_port_shutdown tipc_port_recv_msg->tipc_port_rcv tipc_port_recv_sections->tipc_port_iovec_rcv release->tipc_release accept->tipc_accept bind->tipc_bind get_name->tipc_getname poll->tipc_poll send_msg->tipc_sendmsg send_packet->tipc_send_packet send_stream->tipc_send_stream recv_msg->tipc_recvmsg recv_stream->tipc_recv_stream connect->tipc_connect listen->tipc_listen shutdown->tipc_shutdown setsockopt->tipc_setsockopt getsockopt->tipc_getsockopt Above changes have no impact on current users of the functions. Signed-off-by: Ying Xue Reviewed-by: Jon Maloy Signed-off-by: David S. Miller

tipc: delay delete of link when failover is needed

2014-02-13T22:57:07Z

When a bearer is disabled, all its attached links are deleted. Ideally, we should do link failover to redundant links on other bearers, if there are any, in such cases. This would be consistent with current behavior when a link is reset, but not deleted. However, due to the complexity involved, and the (wrongly) perceived low demand for this feature, it was never implemented until now. We mark the doomed link for deletion with a new flag, but wait until the failover process is finished before we actually delete it. With the improved link tunnelling/failover code introduced earlier in this commit series, it is now easy to identify a spot in the code where the failover is finished and it is safe to delete the marked link. Moreover, the test for the flag and the deletion can be done synchronously, and outside the most time critical data path. Signed-off-by: Jon Maloy Reviewed-by: Ying Xue Signed-off-by: David S. Miller