kernel.git/net/rds/connection.c, branch linux-4.13.y

rds: tcp: set linger to 1 when unloading a rds-tcp

2017-06-22T15:34:04Z

If we are unloading the rds_tcp module, we can set linger to 1 and drop pending packets to accelerate reconnect. The peer will end up resetting the connection based on new generation numbers of the new incarnation, so hanging on to unsent TCP packets via linger is mostly pointless in this case. Signed-off-by: Sowmini Varadhan Tested-by: Jenny Xu Signed-off-by: David S. Miller

rds: tcp: remove cp_outgoing

2017-06-16T16:45:14Z

After commit 1a0e100fb2c9 ("RDS: TCP: Force every connection to be initiated by numerically smaller IP address") we no longer need the logic associated with cp_outgoing, so clean up usage of this field. Signed-off-by: Sowmini Varadhan Tested-by: Imanti Mendez Signed-off-by: David S. Miller

rds: tcp: allow progress of rds_conn_shutdown if the rds_connection is marked ERROR by an intervening FIN

2017-04-03T02:41:00Z

rds_conn_shutdown() runs in workq context, and marks the rds_connection as DISCONNECTING before quiescing Tx/Rx paths. However, after all I/O has quiesced, we may still find the rds_connection state to be RDS_CONN_ERROR if an intervening FIN was processed in softirq context. This is not a fatal error: rds_conn_shutdown() should continue the shutdown, and there is no need to log noisy messages about this event. Signed-off-by: Sowmini Varadhan Acked-by: Santosh Shilimkar Signed-off-by: David S. Miller

rds: tcp: Take explicit refcounts on struct net

2017-03-07T22:09:59Z

It is incorrect for the rds_connection to piggyback on the sock_net() refcount for the netns because this gives rise to a chicken-and-egg problem during rds_conn_destroy. Instead explicitly take a ref on the net, and hold the netns down till the connection tear-down is complete. Reported-by: Dmitry Vyukov Signed-off-by: Sowmini Varadhan Signed-off-by: David S. Miller

RDS: mark few internal functions static to make sparse build happy

2017-01-02T22:02:40Z

Fixes below warnings: warning: symbol 'rds_send_probe' was not declared. Should it be static? warning: symbol 'rds_send_ping' was not declared. Should it be static? warning: symbol 'rds_tcp_accept_one_path' was not declared. Should it be static? warning: symbol 'rds_walk_conn_path_info' was not declared. Should it be static? Signed-off-by: Santosh Shilimkar

RDS: TCP: Force every connection to be initiated by numerically smaller IP address

2016-11-17T18:35:18Z

When 2 RDS peers initiate an RDS-TCP connection simultaneously, there is a potential for "duelling syns" on either/both sides. See commit 241b271952eb ("RDS-TCP: Reset tcp callbacks if re-using an outgoing socket in rds_tcp_accept_one()") for a description of this condition, and the arbitration logic which ensures that the numerically large IP address in the TCP connection is bound to the RDS_TCP_PORT ("canonical ordering"). The rds_connection should not be marked as RDS_CONN_UP until the arbitration logic has converged for the following reason. The sender may start transmitting RDS datagrams as soon as RDS_CONN_UP is set, and since the sender removes all datagrams from the rds_connection's cp_retrans queue based on TCP acks. If the TCP ack was sent from a tcp socket that got reset as part of duel aribitration (but before data was delivered to the receivers RDS socket layer), the sender may end up prematurely freeing the datagram, and the datagram is no longer reliably deliverable. This patch remedies that condition by making sure that, upon receipt of 3WH completion state change notification of TCP_ESTABLISHED in rds_tcp_state_change, we mark the rds_connection as RDS_CONN_UP if, and only if, the IP addresses and ports for the connection are canonically ordered. In all other cases, rds_tcp_state_change will force an rds_conn_path_drop(), and rds_queue_reconnect() on both peers will restart the connection to ensure canonical ordering. A side-effect of enforcing this condition in rds_tcp_state_change() is that rds_tcp_accept_one_path() can now be refactored for simplicity. It is also no longer possible to encounter an RDS_CONN_UP connection in the arbitration logic in rds_tcp_accept_one(). Signed-off-by: Sowmini Varadhan Acked-by: Santosh Shilimkar Signed-off-by: David S. Miller

RDS: TCP: Track peer's connection generation number

2016-11-17T18:35:18Z

The RDS transport has to be able to distinguish between two types of failure events: (a) when the transport fails (e.g., TCP connection reset) but the RDS socket/connection layer on both sides stays the same (b) when the peer's RDS layer itself resets (e.g., due to module reload or machine reboot at the peer) In case (a) both sides must reconnect and continue the RDS messaging without any message loss or disruption to the message sequence numbers, and this is achieved by rds_send_path_reset(). In case (b) we should reset all rds_connection state to the new incarnation of the peer. Examples of state that needs to be reset are next expected rx sequence number from, or messages to be retransmitted to, the new incarnation of the peer. To achieve this, the RDS handshake probe added as part of commit 5916e2c1554f ("RDS: TCP: Enable multipath RDS for TCP") is enhanced so that sender and receiver of the RDS ping-probe will add a generation number as part of the RDS_EXTHDR_GEN_NUM extension header. Each peer stores local and remote generation numbers as part of each rds_connection. Changes in generation number will be detected via incoming handshake probe ping request or response and will allow the receiver to reset rds_connection state. Signed-off-by: Sowmini Varadhan Acked-by: Santosh Shilimkar Signed-off-by: David S. Miller

rds: Remove unused rds_conn_error

2016-10-17T15:07:22Z

This macro's last use was removed in commit d769ef81d5b59 ("RDS: Update rds_conn_shutdown to work with rds_conn_path") so make the macro and the __rds_conn_error function definition and declaration disappear. Signed-off-by: Joe Perches Acked-by: Sowmini Varadhan Acked-by: Santosh Shilimkar Signed-off-by: David S. Miller

RDS: TCP: Enable multipath RDS for TCP

2016-07-15T18:36:58Z

Use RDS probe-ping to compute how many paths may be used with the peer, and to synchronously start the multiple paths. If mprds is supported, hash outgoing traffic to one of multiple paths in rds_sendmsg() when multipath RDS is supported by the transport. CC: Santosh Shilimkar Signed-off-by: Sowmini Varadhan Acked-by: Santosh Shilimkar Signed-off-by: David S. Miller

RDS: TCP: Simplify reconnect to avoid duelling reconnnect attempts

2016-07-01T20:45:17Z

When reconnecting, the peer with the smaller IP address will initiate the reconnect, to avoid needless duelling SYN issues. Acked-by: Santosh Shilimkar Signed-off-by: Sowmini Varadhan Signed-off-by: David S. Miller