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* RDS: TCP: Synchronize accept() and connect() paths on t_conn_lock.Sowmini Varadhan2016-05-031-0/+8
| | | | | | | | | | | | | | | | | | | | | | | | | An arbitration scheme for duelling SYNs is implemented as part of commit 241b271952eb ("RDS-TCP: Reset tcp callbacks if re-using an outgoing socket in rds_tcp_accept_one()") which ensures that both nodes involved will arrive at the same arbitration decision. However, this needs to be synchronized with an outgoing SYN to be generated by rds_tcp_conn_connect(). This commit achieves the synchronization through the t_conn_lock mutex in struct rds_tcp_connection. The rds_conn_state is checked in rds_tcp_conn_connect() after acquiring the t_conn_lock mutex. A SYN is sent out only if the RDS connection is not already UP (an UP would indicate that rds_tcp_accept_one() has completed 3WH, so no SYN needs to be generated). Similarly, the rds_conn_state is checked in rds_tcp_accept_one() after acquiring the t_conn_lock mutex. The only acceptable states (to allow continuation of the arbitration logic) are UP (i.e., outgoing SYN was SYN-ACKed by peer after it sent us the SYN) or CONNECTING (we sent outgoing SYN before we saw incoming SYN). Signed-off-by: Sowmini Varadhan <sowmini.varadhan@oracle.com> Acked-by: Santosh Shilimkar <santosh.shilimkar@oracle.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* RDS-TCP: Support multiple RDS-TCP listen endpoints, one per netns.Sowmini Varadhan2015-08-071-2/+4
| | | | | | | | | | | | | | | | | | | | Register pernet subsys init/stop functions that will set up and tear down per-net RDS-TCP listen endpoints. Unregister pernet subusys functions on 'modprobe -r' to clean up these end points. Enable keepalive on both accept and connect socket endpoints. The keepalive timer expiration will ensure that client socket endpoints will be removed as appropriate from the netns when an interface is removed from a namespace. Register a device notifier callback that will clean up all sockets (and thus avoid the need to wait for keepalive timeout) when the loopback device is unregistered from the netns indicating that the netns is getting deleted. Signed-off-by: Sowmini Varadhan <sowmini.varadhan@oracle.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* RDS-TCP: Make RDS-TCP work correctly when it is set up in a netns other than ↵Sowmini Varadhan2015-08-071-1/+2
| | | | | | | | | | | init_net Open the sockets calling sock_create_kern() with the correct struct net pointer, and use that struct net pointer when verifying the address passed to rds_bind(). Signed-off-by: Sowmini Varadhan <sowmini.varadhan@oracle.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* net/rds: RDS-TCP: Always create a new rds_sock for an incoming connection.Sowmini Varadhan2015-05-091-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | When running RDS over TCP, the active (client) side connects to the listening ("passive") side at the RDS_TCP_PORT. After the connection is established, if the client side reboots (potentially without even sending a FIN) the server still has a TCP socket in the esablished state. If the server-side now gets a new SYN comes from the client with a different client port, TCP will create a new socket-pair, but the RDS layer will incorrectly pull up the old rds_connection (which is still associated with the stale t_sock and RDS socket state). This patch corrects this behavior by having rds_tcp_accept_one() always create a new connection for an incoming TCP SYN. The rds and tcp state associated with the old socket-pair is cleaned up via the rds_tcp_state_change() callback which would typically be invoked in most cases when the client-TCP sends a FIN on TCP restart, triggering a transition to CLOSE_WAIT state. In the rarer event of client death without a FIN, TCP_KEEPALIVE probes on the socket will detect the stale socket, and the TCP transition to CLOSE state will trigger the RDS state cleanup. Signed-off-by: Sowmini Varadhan <sowmini.varadhan@oracle.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* net/rds: do proper house keeping if connection fails in rds_tcp_conn_connectHerton R. Krzesinski2014-10-031-1/+4
| | | | | | | | | | | | | | | | I see two problems if we consider the sock->ops->connect attempt to fail in rds_tcp_conn_connect. The first issue is that for example we don't remove the previously added rds_tcp_connection item to rds_tcp_tc_list at rds_tcp_set_callbacks, which means that on a next reconnect attempt for the same rds_connection, when rds_tcp_conn_connect is called we can again call rds_tcp_set_callbacks, resulting in duplicated items on rds_tcp_tc_list, leading to list corruption: to avoid this just make sure we call properly rds_tcp_restore_callbacks before we exit. The second issue is that we should also release the sock properly, by setting sock = NULL only if we are returning without error. Signed-off-by: Herton R. Krzesinski <herton@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* rds: Don't disable BH on BH contextYing Xue2012-08-221-2/+2
| | | | | | | | | Since we have already in BH context when *_write_space(), *_data_ready() as well as *_state_change() are called, it's unnecessary to disable BH. Signed-off-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* Merge branch 'master' of ↵David S. Miller2010-09-271-2/+2
|\ | | | | | | | | | | | | | | master.kernel.org:/pub/scm/linux/kernel/git/davem/net-2.6 Conflicts: drivers/net/qlcnic/qlcnic_init.c net/ipv4/ip_output.c
| * net: fix a lockdep splatEric Dumazet2010-09-241-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | We have for each socket : One spinlock (sk_slock.slock) One rwlock (sk_callback_lock) Possible scenarios are : (A) (this is used in net/sunrpc/xprtsock.c) read_lock(&sk->sk_callback_lock) (without blocking BH) <BH> spin_lock(&sk->sk_slock.slock); ... read_lock(&sk->sk_callback_lock); ... (B) write_lock_bh(&sk->sk_callback_lock) stuff write_unlock_bh(&sk->sk_callback_lock) (C) spin_lock_bh(&sk->sk_slock) ... write_lock_bh(&sk->sk_callback_lock) stuff write_unlock_bh(&sk->sk_callback_lock) spin_unlock_bh(&sk->sk_slock) This (C) case conflicts with (A) : CPU1 [A] CPU2 [C] read_lock(callback_lock) <BH> spin_lock_bh(slock) <wait to spin_lock(slock)> <wait to write_lock_bh(callback_lock)> We have one problematic (C) use case in inet_csk_listen_stop() : local_bh_disable(); bh_lock_sock(child); // spin_lock_bh(&sk->sk_slock) WARN_ON(sock_owned_by_user(child)); ... sock_orphan(child); // write_lock_bh(&sk->sk_callback_lock) lockdep is not happy with this, as reported by Tetsuo Handa It seems only way to deal with this is to use read_lock_bh(callbacklock) everywhere. Thanks to Jarek for pointing a bug in my first attempt and suggesting this solution. Reported-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Tested-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com> CC: Jarek Poplawski <jarkao2@gmail.com> Tested-by: Eric Dumazet <eric.dumazet@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* | RDS: cleanup: remove "== NULL"s and "!= NULL"s in ptr comparisonsAndy Grover2010-09-081-1/+1
|/ | | | | | Favor "if (foo)" style over "if (foo != NULL)". Signed-off-by: Andy Grover <andy.grover@oracle.com>
* net: Remove unnecessary semicolons after switch statementsJoe Perches2010-05-171-1/+1
| | | | | | | | Also added an explicit break; to avoid a fallthrough in net/ipv4/tcp_input.c Signed-off-by: Joe Perches <joe@perches.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* net/rds: remove uses of NIPQUAD, use %pI4Joe Perches2010-02-031-4/+3
| | | | | | | Signed-off-by: Joe Perches <joe@perches.com> Cc: Andy Grover <andy.grover@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: David S. Miller <davem@davemloft.net>
* RDS: Add TCP transport to RDSAndy Grover2009-08-231-0/+153
This code allows RDS to be tunneled over a TCP connection. RDMA operations are disabled when using TCP transport, but this frees RDS from the IB/RDMA stack dependency, and allows it to be used with standard Ethernet adapters, or in a VM. Signed-off-by: Andy Grover <andy.grover@oracle.com> Signed-off-by: David S. Miller <davem@davemloft.net>
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