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

rds: Make sure updates to cp_send_gen can be observed

2017-07-20T22:33:01Z

cp->cp_send_gen is treated as a normal variable, although it may be used by different threads. This is fixed by using {READ,WRITE}_ONCE when it is incremented and READ_ONCE when it is read outside the {acquire,release}_in_xmit protection. Normative reference from the Linux-Kernel Memory Model: Loads from and stores to shared (but non-atomic) variables should be protected with the READ_ONCE(), WRITE_ONCE(), and ACCESS_ONCE(). Clause 5.1.2.4/25 in the C standard is also relevant. Signed-off-by: Håkon Bugge Reviewed-by: Knut Omang Acked-by: Santosh Shilimkar Signed-off-by: David S. Miller

rds: tcp: send handshake ping-probe from passive endpoint

2017-06-22T15:34:04Z

The RDS handshake ping probe added by commit 5916e2c1554f ("RDS: TCP: Enable multipath RDS for TCP") is sent from rds_sendmsg() before the first data packet is sent to a peer. If the conversation is not bidirectional (i.e., one side is always passive and never invokes rds_sendmsg()) and the passive side restarts its rds_tcp module, a new HS ping probe needs to be sent, so that the number of paths can be re-established. This patch achieves that by sending a HS ping probe from rds_tcp_accept_one() when c_npaths is 0 (i.e., we have not done a handshake probe with this peer yet). Signed-off-by: Sowmini Varadhan Tested-by: Jenny Xu Signed-off-by: David S. Miller

rds: tcp: various endian-ness fixes

2017-06-16T16:45:15Z

Found when testing between sparc and x86 machines on different subnets, so the address comparison patterns hit the corner cases and brought out some bugs fixed by this patch. Signed-off-by: Sowmini Varadhan Tested-by: Imanti Mendez Acked-by: Santosh Shilimkar Signed-off-by: David S. Miller

RDS: make message size limit compliant with spec

2017-01-02T22:02:57Z

RDS support max message size as 1M but the code doesn't check this in all cases. Patch fixes it for RDMA & non-RDMA and RDS MR size and its enforced irrespective of underlying transport. Signed-off-by: Avinash Repaka Signed-off-by: Santosh Shilimkar

RDS: RDMA: Fix the composite message user notification

2017-01-02T22:02:54Z

When application sends an RDS RDMA composite message consist of RDMA transfer to be followed up by non RDMA payload, it expect to be notified *only* when the full message gets delivered. RDS RDMA notification doesn't behave this way though. Thanks to Venkat for debug and root casuing the issue where only first part of the message(RDMA) was successfully delivered but remainder payload delivery failed. In that case, application should not be notified with a false positive of message delivery success. Fix this case by making sure the user gets notified only after the full message delivery. Reviewed-by: Venkat Venkatsubra Signed-off-by: Santosh Shilimkar

RDS: RDMA: return appropriate error on rdma map failures

2017-01-02T22:02:46Z

The first message to a remote node should prompt a new connection even if it is RDMA operation. For RDMA operation the MR mapping can fail because connections is not yet up. Since the connection establishment is asynchronous, we make sure the map failure because of unavailable connection reach to the user by appropriate error code. Before returning to the user, lets trigger the connection so that its ready for the next retry. Signed-off-by: Santosh Shilimkar

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: 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: 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: Rework path specific indirections

2016-07-01T20:45:17Z

Refactor code to avoid separate indirections for single-path and multipath transports. All transports (both single and mp-capable) will get a pointer to the rds_conn_path, and can trivially derive the rds_connection from the ->cp_conn. Acked-by: Santosh Shilimkar Signed-off-by: Sowmini Varadhan Signed-off-by: David S. Miller