linux.git/net/rds/threads.c, branch v4.11

rds: Remove duplicate prefix from rds_conn_path_error use

2016-10-17T15:07:22+00:00

rds_conn_path_error already prefixes "RDS:" to the output.

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

2016-07-15T18:36:58+00:00

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

2016-07-01T20:45:17+00:00

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

RDS: TCP: Hooks to set up a single connection path

2016-07-01T20:45:17+00:00

This patch adds ->conn_path_connect callbacks in the rds_transport
that are used to set up a single connection path.

Acked-by: Santosh Shilimkar 
Signed-off-by: Sowmini Varadhan 
Signed-off-by: David S. Miller

RDS: TCP: make receive path use the rds_conn_path

2016-07-01T20:45:17+00:00

The ->sk_user_data contains a pointer to the rds_conn_path
for the socket. Use this consistently in the rds_tcp_data_ready
callbacks to get the rds_conn_path for rds_recv_incoming.

Acked-by: Santosh Shilimkar 
Signed-off-by: Sowmini Varadhan 
Signed-off-by: David S. Miller

RDS: Update rds_conn_shutdown to work with rds_conn_path

2016-06-15T06:50:44+00:00

This commit changes rds_conn_shutdown to take a rds_conn_path *
argument, allowing it to shutdown paths other than c_path[0] for
MP-capable transports.

Signed-off-by: Sowmini Varadhan 
Signed-off-by: David S. Miller

RDS: Add rds_conn_path_error()

2016-06-15T06:50:43+00:00

rds_conn_path_error() is the MP-aware analog of rds_conn_error,
to be used by multipath-capable callers.

Signed-off-by: Sowmini Varadhan 
Signed-off-by: David S. Miller

RDS: Pass rds_conn_path to rds_send_xmit()

2016-06-15T06:50:43+00:00

Pass a struct rds_conn_path to rds_send_xmit so that MP capable
transports can transmit packets on something other than c_path[0].
The eventual goal for MP capable transports is to hash the rds
socket to a path based on the bound local address/port, and use
this path as the argument to rds_send_xmit()

Signed-off-by: Sowmini Varadhan 
Signed-off-by: David S. Miller

RDS: split out connection specific state from rds_connection to rds_conn_path

2016-06-15T06:50:41+00:00

In preparation for multipath RDS, split the rds_connection
structure into a base structure, and a per-path struct rds_conn_path.
The base structure tracks information and locks common to all
paths. The workqs for send/recv/shutdown etc are tracked per
rds_conn_path. Thus the workq callbacks now work with rds_conn_path.

This commit allows for one rds_conn_path per rds_connection, and will
be extended into multiple conn_paths in  subsequent commits.

Signed-off-by: Sowmini Varadhan 
Signed-off-by: David S. Miller

RDS: TCP: fix race windows in send-path quiescence by rds_tcp_accept_one()

2016-06-07T22:10:15+00:00

The send path needs to be quiesced before resetting callbacks from
rds_tcp_accept_one(), and commit eb192840266f ("RDS:TCP: Synchronize
rds_tcp_accept_one with rds_send_xmit when resetting t_sock") achieves
this using the c_state and RDS_IN_XMIT bit following the pattern
used by rds_conn_shutdown(). However this leaves the possibility
of a race window as shown in the sequence below
    take t_conn_lock in rds_tcp_conn_connect
    send outgoing syn to peer
    drop t_conn_lock in rds_tcp_conn_connect
    incoming from peer triggers rds_tcp_accept_one, conn is
	marked CONNECTING
    wait for RDS_IN_XMIT to quiesce any rds_send_xmit threads
    call rds_tcp_reset_callbacks
    [.. race-window where incoming syn-ack can cause the conn
	to be marked UP from rds_tcp_state_change ..]
    lock_sock called from rds_tcp_reset_callbacks, and we set
	t_sock to null
As soon as the conn is marked UP in the race-window above, rds_send_xmit()
threads will proceed to rds_tcp_xmit and may encounter a null-pointer
deref on the t_sock.

Given that rds_tcp_state_change() is invoked in softirq context, whereas
rds_tcp_reset_callbacks() is in workq context, and testing for RDS_IN_XMIT
after lock_sock could result in a deadlock with tcp_sendmsg, this
commit fixes the race by using a new c_state, RDS_TCP_RESETTING, which
will prevent a transition to RDS_CONN_UP from rds_tcp_state_change().

Signed-off-by: Sowmini Varadhan 
Acked-by: Santosh Shilimkar 
Signed-off-by: David S. Miller