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2012-12-07tipc: refactor accept() code for improved readabilityPaul Gortmaker
In TIPC's accept() routine, there is a large block of code relating to initialization of a new socket, all within an if condition checking if the allocation succeeded. Here, we simply flip the check of the if, so that the main execution path stays at the same indentation level, which improves readability. If the allocation fails, we jump to an already existing exit label. Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2012-12-07tipc: add lock nesting notation to quiet lockdep warningYing Xue
TIPC accept() call grabs the socket lock on a newly allocated socket while holding the socket lock on an old socket. But lockdep worries that this might be a recursive lock attempt: [ INFO: possible recursive locking detected ] --------------------------------------------- kworker/u:0/6 is trying to acquire lock: (sk_lock-AF_TIPC){+.+.+.}, at: [<c8c1226c>] accept+0x15c/0x310 [tipc] but task is already holding lock: (sk_lock-AF_TIPC){+.+.+.}, at: [<c8c12138>] accept+0x28/0x310 [tipc] other info that might help us debug this: Possible unsafe locking scenario: CPU0 ---- lock(sk_lock-AF_TIPC); lock(sk_lock-AF_TIPC); *** DEADLOCK *** May be due to missing lock nesting notation [...] Tell lockdep that this locking is safe by using lock_sock_nested(). This is similar to what was done in commit 5131a184a3458d9 for SCTP code ("SCTP: lock_sock_nested in sctp_sock_migrate"). Also note that this is isn't something that is seen normally, as it was uncovered with some experimental work-in-progress code not yet ready for mainline. So no need for stable backports or similar of this commit. Signed-off-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2012-12-07tipc: eliminate connection setup for implied connect in recv_msg()Ying Xue
As connection setup is now completed asynchronously in BH context, in the function filter_connect(), the corresponding code in recv_msg() becomes redundant. Signed-off-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2012-12-07tipc: introduce non-blocking socket connectYing Xue
TIPC has so far only supported blocking connect(), meaning that a call to connect() doesn't return until either the connection is fully established, or an error occurs. This has proved insufficient for many users, so we now introduce non-blocking connect(), analogous to how this is done in TCP and other protocols. With this feature, if a connection cannot be established instantly, connect() will return the error code "-EINPROGRESS". If the user later calls connect() again, he will either have the return code "-EALREADY" or "-EISCONN", depending on whether the connection has been established or not. The user must have explicitly set the socket to be non-blocking (SOCK_NONBLOCK or O_NONBLOCK, depending on method used), so unless for some reason they had set this already (the socket would anyway remain blocking in current TIPC) this change should be completely backwards compatible. It is also now possible to call select() or poll() to wait for the completion of a connection. An effect of the above is that the actual completion of a connection may now be performed asynchronously, independent of the calls from user space. Therefore, we now execute this code in BH context, in the function filter_rcv(), which is executed upon reception of messages in the socket. Signed-off-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> [PG: minor refactoring for improved connect/disconnect function names] Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2012-12-07tipc: consolidate connection-oriented message reception in one functionYing Xue
Handling of connection-related message reception is currently scattered around at different places in the code. This makes it harder to verify that things are handled correctly in all possible scenarios. So we consolidate the existing processing of connection-oriented message reception in a single routine. In the process, we convert the chain of if/else into a switch/case for improved readability. A cast on the socket_state in the switch is needed to avoid compile warnings on 32 bit, like "net/tipc/socket.c:1252:2: warning: case value ‘4294967295’ not in enumerated type". This happens because existing tipc code pseudo extends the default linux socket state values with: #define SS_LISTENING -1 /* socket is listening */ #define SS_READY -2 /* socket is connectionless */ It may make sense to add these as _positive_ values to the existing socket state enum list someday, vs. these already existing defines. Signed-off-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> [PG: add cast to fix warning; remove returns from middle of switch] Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2012-12-07tipc: standardize across connect/disconnect function namingPaul Gortmaker
Currently we have tipc_disconnect and tipc_disconnect_port. It is not clear from the names alone, what they do or how they differ. It turns out that tipc_disconnect just deals with the port locking and then calls tipc_disconnect_port which does all the work. If we rename as follows: tipc_disconnect_port --> __tipc_disconnect then we will be following typical linux convention, where: __tipc_disconnect: "raw" function that does all the work. tipc_disconnect: wrapper that deals with locking and then calls the real core __tipc_disconnect function With this, the difference is immediately evident, and locking violations are more apt to be spotted by chance while working on, or even just while reading the code. On the connect side of things, we currently only have the single "tipc_connect2port" function. It does both the locking at enter/exit, and the core of the work. Pending changes will make it desireable to have the connect be a two part locking wrapper + worker function, just like the disconnect is already. Here, we make the connect look just like the updated disconnect case, for the above reason, and for consistency. In the process, we also get rid of the "2port" suffix that was on the original name, since it adds no descriptive value. On close examination, one might notice that the above connect changes implicitly move the call to tipc_link_get_max_pkt() to be within the scope of tipc_port_lock() protected region; when it was not previously. We don't see any issues with this, and it is in keeping with __tipc_connect doing the work and tipc_connect just handling the locking. Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2012-12-07tipc: change sk_receive_queue upper limitJon Maloy
The sk_recv_queue upper limit for connectionless sockets has empirically turned out to be too low. When we double the current limit we get much fewer rejected messages and no noticable negative side-effects. Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2012-12-07tipc: eliminate aggregate sk_receive_queue limitYing Xue
As a complement to the per-socket sk_recv_queue limit, TIPC keeps a global atomic counter for the sum of sk_recv_queue sizes across all tipc sockets. When incremented, the counter is compared to an upper threshold value, and if this is reached, the message is rejected with error code TIPC_OVERLOAD. This check was originally meant to protect the node against buffer exhaustion and general CPU overload. However, all experience indicates that the feature not only is redundant on Linux, but even harmful. Users run into the limit very often, causing disturbances for their applications, while removing it seems to have no negative effects at all. We have also seen that overall performance is boosted significantly when this bottleneck is removed. Furthermore, we don't see any other network protocols maintaining such a mechanism, something strengthening our conviction that this control can be eliminated. As a result, the atomic variable tipc_queue_size is now unused and so it can be deleted. There is a getsockopt call that used to allow reading it; we retain that but just return zero for maximum compatibility. Signed-off-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Cc: Neil Horman <nhorman@tuxdriver.com> [PG: phase out tipc_queue_size as pointed out by Neil Horman] Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2012-12-06tipc: remove obsolete flush of stale reassembly bufferErik Hugne
Each link instance has a periodic job checking if there is a stale ongoing message reassembly associated to the link. If no new fragment has been received during the last 4*[link_tolerance] period, it is assumed the missing fragment will never arrive. As a consequence, the reassembly buffer is discarded, and a gap in the message sequence occurs. This assumption is wrong. After we abandoned our ambition to develop packet routing for multi-cluster networks, only single-hop packet transfer remains as an option. For those, all packets are guaranteed to be delivered in sequence to the defragmentation layer. Any failure to achieve sequenced delivery will eventually lead to link reset, and the reassembly buffer will be flushed anyway. So we just remove this periodic check, which is now obsolete. Signed-off-by: Erik Hugne <erik.hugne@ericsson.com> Acked-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> [PG: also delete get/inc_timer count, since they are now unused] Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2012-11-22tipc: delete TIPC_ADVANCED Kconfig variablePaul Gortmaker
There used to be a time when TIPC had lots of Kconfig knobs the end user could alter, but they have all been made automatic or obsolete, with the exception of CONFIG_TIPC_PORTS. This previously existing set of options was all hidden under the TIPC_ADVANCED setting, which does not exist in any code, but only in Kconfig scope. Having this now, just to hide the one remaining "advanced" option no longer makes sense. Remove it. Also get rid of the ifdeffery in the TIPC code that allowed for TIPC_PORTS to be possibly undefined. Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2012-11-22tipc: eliminate an unnecessary cast of node variableYing Xue
As the variable:node is currently defined to u32 type, it is unnecessary to cast its type to u32 again when using it. Signed-off-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2012-11-22tipc: introduce message to synchronize broadcast linkJon Maloy
Upon establishing a first link between two nodes, there is currently a risk that the two endpoints will disagree on exactly which sequence number reception and acknowleding of broadcast packets should start. The following scenarios may happen: 1: Node A sends an ACTIVATE message to B, telling it to start acking packets from sequence number N. 2: Node A sends out broadcast N, but does not expect an acknowledge from B, since B is not yet in its broadcast receiver's list. 3: Node A receives ACK for N from all nodes except B, and releases packet N. 4: Node B receives the ACTIVATE, activates its link endpoint, and stores the value N as sequence number of first expected packet. 5: Node B sends a NAME_DISTR message to A. 6: Node A receives the NAME_DISTR message, and activates its endpoint. At this moment B is added to A's broadcast receiver's set. Node A also sets sequence number 0 as the first broadcast packet to be received from B. 7: Node A sends broadcast N+1. 8: B receives N+1, determines there is a gap in the sequence, since it is expecting N, and sends a NACK for N back to A. 9: Node A has already released N, so no retransmission is possible. The broadcast link in direction A->B is stale. In addition to, or instead of, 7-9 above, the following may happen: 10: Node B sends broadcast M > 0 to A. 11: Node A receives M, falsely decides there must be a gap, since it is expecting packet 0, and asks for retransmission of packets [0,M-1]. 12: Node B has already released these packets, so the broadcast link is stale in direction B->A. We solve this problem by introducing a new unicast message type, BCAST_PROTOCOL/STATE, to convey the sequence number of the next sent broadcast packet to the other endpoint, at exactly the moment that endpoint is added to the own node's broadcast receivers list, and before any other unicast messages are permitted to be sent. Furthermore, we don't allow any node to start receiving and processing broadcast packets until this new synchronization message has been received. To maintain backwards compatibility, we still open up for broadcast reception if we receive a NAME_DISTR message without any preceding broadcast sync message. In this case, we must assume that the other end has an older code version, and will never send out the new synchronization message. Hence, for mixed old and new nodes, the issue arising in 7-12 of the above may happen with the same probability as before. Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2012-11-22tipc: rename supported flag to recv_permittedYing Xue
Rename the "supported" flag in bclink structure to "recv_permitted" to better reflect what it is used for. When this flag is set for a given node, we are permitted to receive and acknowledge broadcast messages from that node. Convert it to a bool at the same time, since it is not used to store any numerical values. Signed-off-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2012-11-22tipc: remove supportable flag from bclink structureYing Xue
The "supportable" flag in bclink structure is a compatibility flag indicating whether a peer node is capable of receiving TIPC broadcast messages. However, all TIPC versions since tipc-1.5, and after the inclusion in the upstream Linux kernel in 2006, support this capability. It is highly unlikely that anybody is still using such an old version of TIPC, let alone that they want to mix it with TIPC-2.0 nodes. Therefore, we now remove the "supportable" flag. Signed-off-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2012-11-22tipc: remove the bearer congestion mechanismYing Xue
Currently at the TIPC bearer layer there is the following congestion mechanism: Once sending packets has failed via that bearer, the bearer will be flagged as being in congested state at once. During bearer congestion, all packets arriving at link will be queued on the link's outgoing buffer. When we detect that the state of bearer congestion has relaxed (e.g. some packets are received from the bearer) we will try our best to push all packets in the link's outgoing buffer until the buffer is empty, or until the bearer is congested again. However, in fact the TIPC bearer never receives any feedback from the device layer whether a send was successful or not, so it must always assume it was successful. Therefore, the bearer congestion mechanism as it exists currently is of no value. But the bearer blocking state is still useful for us. For example, when the physical media goes down/up, we need to change the state of the links bound to the bearer. So the code maintaing the state information is not removed. Signed-off-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2012-11-22tipc: wake up all waiting threads at socket shutdownYing Xue
When a socket is shut down, we should wake up all thread sleeping on it, instead of just one of them. Otherwise, when several threads are polling the same socket, and one of them does shutdown(), the remaining threads may end up sleeping forever. Also, to align socket usage with common practice in other stacks, we use one of the common socket callback handlers, sk_state_change(), to wake up pending users. This is similar to the usage in e.g. inet_shutdown(). [net/ipv4/af_inet.c]. Signed-off-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2012-11-21tipc: return POLLOUT for sockets in an unconnected stateErik Hugne
If an implied connect is attempted on a nonblocking STREAM/SEQPACKET socket during link congestion, the connect message will be discarded and sendmsg will return EAGAIN. This is normal behavior, and the application is expected to poll the socket until POLLOUT is set, after which the connection attempt can be retried. However, the POLLOUT flag is never set for unconnected sockets and poll() always returns a zero mask. The application is then left without a trigger for when it can make another attempt at sending the message. The solution is to check if we're polling on an unconnected socket and set the POLLOUT flag if the TIPC port owned by this socket is not congested. The TIPC ports waiting on a specific link will be marked as 'not congested' when the link congestion have abated. Signed-off-by: Erik Hugne <erik.hugne@ericsson.com> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2012-11-21tipc: fix race/inefficiencies in poll/wait behaviourYing Xue
When an application blocks at poll/select on a TIPC socket while requesting a specific event mask, both the filter_rcv() and wakeupdispatch() case will wake it up unconditionally whenever the state changes (i.e an incoming message arrives, or congestion has subsided). No mask is used. To avoid this, we populate sk->sk_data_ready and sk->sk_write_space with tipc_data_ready and tipc_write_space respectively, which makes tipc more in alignment with the rest of the networking code. These pass the exact set of possible events to the waker in fs/select.c hence avoiding waking up blocked processes unnecessarily. In doing so, we uncover another issue -- that there needs to be a memory barrier in these poll/receive callbacks, otherwise we are subject to the the same race as documented above wq_has_sleeper() [in commit a57de0b4 "net: adding memory barrier to the poll and receive callbacks"]. So we need to replace poll_wait() with sock_poll_wait() and use rcu protection for the sk->sk_wq pointer in these two new functions. Signed-off-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2012-11-03tipc: do not use tasklet_disable before tasklet_killXiaotian Feng
If tasklet_disable() is called before related tasklet handled, tasklet_kill will never be finished. tasklet_kill is enough. Signed-off-by: Xiaotian Feng <dannyfeng@tencent.com> Cc: Jon Maloy <jon.maloy@ericsson.com> Cc: Allan Stephens <allan.stephens@windriver.com> Cc: "David S. Miller" <davem@davemloft.net> Cc: netdev@vger.kernel.org Cc: tipc-discussion@lists.sourceforge.net Signed-off-by: David S. Miller <davem@davemloft.net>
2012-10-04tipc: prevent dropped connections due to rcvbuf overflowErik Hugne
When large buffers are sent over connected TIPC sockets, it is likely that the sk_backlog will be filled up on the receiver side, but the TIPC flow control mechanism is happily unaware of this since that is based on message count. The sender will receive a TIPC_ERR_OVERLOAD message when this occurs and drop it's side of the connection, leaving it stale on the receiver end. By increasing the sk_rcvbuf to a 'worst case' value, we avoid the overload caused by a full backlog queue and the flow control will work properly. This worst case value is the max TIPC message size times the flow control window, multiplied by two because a sender will transmit up to double the window size before a port is marked congested. We multiply this by 2 to account for the sk_buff and other overheads. Signed-off-by: Erik Hugne <erik.hugne@ericsson.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2012-09-18net/tipc/name_table.c: Remove unecessary semicolonPeter Senna Tschudin
Found by http://coccinelle.lip6.fr/ Signed-off-by: Peter Senna Tschudin <peter.senna@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2012-09-10netlink: Rename pid to portid to avoid confusionEric W. Biederman
It is a frequent mistake to confuse the netlink port identifier with a process identifier. Try to reduce this confusion by renaming fields that hold port identifiers portid instead of pid. I have carefully avoided changing the structures exported to userspace to avoid changing the userspace API. I have successfully built an allyesconfig kernel with this change. Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com> Acked-by: Stephen Hemminger <shemminger@vyatta.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2012-08-20tipc: eliminate configuration for maximum number of name publicationsYing Xue
Gets rid of the need for users to specify the maximum number of name publications supported by TIPC. TIPC now automatically provides support for the maximum number of name publications to 65535. Signed-off-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2012-08-20tipc: eliminate configuration for maximum number of name subscriptionsYing Xue
Gets rid of the need for users to specify the maximum number of name subscriptions supported by TIPC. TIPC now automatically provides support for the maximum number of name subscriptions to 65535. Signed-off-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2012-08-20tipc: add __read_mostly annotations to several global variablesYing Xue
Added to the following: - tipc_random - tipc_own_addr - tipc_max_ports - tipc_net_id - tipc_remote_management - handler_enabled The above global variables are read often, but written rarely. Use __read_mostly to prevent them being on the same cacheline as another variable which is written to often, which would cause cacheline bouncing. Signed-off-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2012-08-20tipc: convert tipc_nametbl_size type from variable to macroYing Xue
There is nothing changing this variable dynamically, so change it to a macro to make that more obvious when reading the code. Signed-off-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2012-08-20tipc: change tipc_net_start routine return value typeYing Xue
Since now tipc_net_start() always returns a success code - 0, its return value type should be changed from integer to void, which can avoid unnecessary check for its return value. Signed-off-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2012-08-20tipc: manually inline single use media_name_valid routineYing Xue
After eliminating the mechanism which checks whether all letters in media name string are within a given character set, the media_name_valid routine becomes trivial. It is also only used once, so it is unnecessary to keep it as a separate function. Signed-off-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2012-08-20tipc: remove pointless name sanity check and tipc_alphabet arrayYing Xue
There is no real reason to check whether all letters in the given media name and network interface name are within the character set defined in tipc_alphabet array. Even if we eliminate the checking, the rest of checking conditions in tipc_enable_bearer() can ensure we do not enable an invalid or illegal bearer. Signed-off-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2012-08-20tipc: fix lockdep warning during bearer initializationYing Xue
When the lockdep validator is enabled, it will report the below warning when we enable a TIPC bearer: [ INFO: possible irq lock inversion dependency detected ] --------------------------------------------------------- Possible interrupt unsafe locking scenario: CPU0 CPU1 ---- ---- lock(ptype_lock); local_irq_disable(); lock(tipc_net_lock); lock(ptype_lock); <Interrupt> lock(tipc_net_lock); *** DEADLOCK *** the shortest dependencies between 2nd lock and 1st lock: -> (ptype_lock){+.+...} ops: 10 { [...] SOFTIRQ-ON-W at: [<c1089418>] __lock_acquire+0x528/0x13e0 [<c108a360>] lock_acquire+0x90/0x100 [<c1553c38>] _raw_spin_lock+0x38/0x50 [<c14651ca>] dev_add_pack+0x3a/0x60 [<c182da75>] arp_init+0x1a/0x48 [<c182dce5>] inet_init+0x181/0x27e [<c1001114>] do_one_initcall+0x34/0x170 [<c17f7329>] kernel_init+0x110/0x1b2 [<c155b6a2>] kernel_thread_helper+0x6/0x10 [...] ... key at: [<c17e4b10>] ptype_lock+0x10/0x20 ... acquired at: [<c108a360>] lock_acquire+0x90/0x100 [<c1553c38>] _raw_spin_lock+0x38/0x50 [<c14651ca>] dev_add_pack+0x3a/0x60 [<c8bc18d2>] enable_bearer+0xf2/0x140 [tipc] [<c8bb283a>] tipc_enable_bearer+0x1ba/0x450 [tipc] [<c8bb3a04>] tipc_cfg_do_cmd+0x5c4/0x830 [tipc] [<c8bbc032>] handle_cmd+0x42/0xd0 [tipc] [<c148e802>] genl_rcv_msg+0x232/0x280 [<c148d3f6>] netlink_rcv_skb+0x86/0xb0 [<c148e5bc>] genl_rcv+0x1c/0x30 [<c148d144>] netlink_unicast+0x174/0x1f0 [<c148ddab>] netlink_sendmsg+0x1eb/0x2d0 [<c1456bc1>] sock_aio_write+0x161/0x170 [<c1135a7c>] do_sync_write+0xac/0xf0 [<c11360f6>] vfs_write+0x156/0x170 [<c11361e2>] sys_write+0x42/0x70 [<c155b0df>] sysenter_do_call+0x12/0x38 [...] } -> (tipc_net_lock){+..-..} ops: 4 { [...] IN-SOFTIRQ-R at: [<c108953a>] __lock_acquire+0x64a/0x13e0 [<c108a360>] lock_acquire+0x90/0x100 [<c15541cd>] _raw_read_lock_bh+0x3d/0x50 [<c8bb874d>] tipc_recv_msg+0x1d/0x830 [tipc] [<c8bc195f>] recv_msg+0x3f/0x50 [tipc] [<c146a5fa>] __netif_receive_skb+0x22a/0x590 [<c146ab0b>] netif_receive_skb+0x2b/0xf0 [<c13c43d2>] pcnet32_poll+0x292/0x780 [<c146b00a>] net_rx_action+0xfa/0x1e0 [<c103a4be>] __do_softirq+0xae/0x1e0 [...] } >From the log, we can see three different call chains between CPU0 and CPU1: Time 0 on CPU0: kernel_init()->inet_init()->dev_add_pack() At time 0, the ptype_lock is held by CPU0 in dev_add_pack(); Time 1 on CPU1: tipc_enable_bearer()->enable_bearer()->dev_add_pack() At time 1, tipc_enable_bearer() first holds tipc_net_lock, and then wants to take ptype_lock to register TIPC protocol handler into the networking stack. But the ptype_lock has been taken by dev_add_pack() on CPU0, so at this time the dev_add_pack() running on CPU1 has to be busy looping. Time 2 on CPU0: netif_receive_skb()->recv_msg()->tipc_recv_msg() At time 2, an incoming TIPC packet arrives at CPU0, hence tipc_recv_msg() will be invoked. In tipc_recv_msg(), it first wants to hold tipc_net_lock. At the moment, below scenario happens: On CPU0, below is our sequence of taking locks: lock(ptype_lock)->lock(tipc_net_lock) On CPU1, our sequence of taking locks looks like: lock(tipc_net_lock)->lock(ptype_lock) Obviously deadlock may happen in this case. But please note the deadlock possibly doesn't occur at all when the first TIPC bearer is enabled. Before enable_bearer() -- running on CPU1 does not hold ptype_lock, so the TIPC receive handler (i.e. recv_msg()) is not registered successfully via dev_add_pack(), so the tipc_recv_msg() cannot be called by recv_msg() even if a TIPC message comes to CPU0. But when the second TIPC bearer is registered, the deadlock can perhaps really happen. To fix it, we will push the work of registering TIPC protocol handler into workqueue context. After the change, both paths taking ptype_lock are always in process contexts, thus, the deadlock should never occur. Signed-off-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2012-08-20tipc: optimize the initialization of network device notifierYing Xue
Ethernet media initialization is only done when TIPC is started or switched to network mode. So the initialization of the network device notifier structure can be moved out of this function and done statically instead. Signed-off-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2012-07-13tipc: remove print_buf and deprecated log buffer codeErik Hugne
The internal log buffer handling functions can now safely be removed since there is no code using it anymore. Requests to interact with the internal tipc log buffer over netlink (in config.c) will report 'obsolete command'. This represents the final removal of any references to a struct print_buf, and the removal of the struct itself. We also get rid of a TIPC specific Kconfig in the process. Finally, log.h is removed since it is not needed anymore. Signed-off-by: Erik Hugne <erik.hugne@ericsson.com> Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2012-07-13tipc: phase out most of the struct print_buf usageErik Hugne
The tipc_printf is renamed to tipc_snprintf, as the new name describes more what the function actually does. It is also changed to take a buffer and length parameter and return number of characters written to the buffer. All callers of this function that used to pass a print_buf are updated. Final removal of the struct print_buf itself will be done synchronously with the pending removal of the deprecated logging code that also was using it. Functions that build up a response message with a list of ports, nametable contents etc. are changed to return the number of characters written to the output buffer. This information was previously hidden in a field of the print_buf struct, and the number of chars written was fetched with a call to tipc_printbuf_validate. This function is removed since it is no longer referenced nor needed. A generic max size ULTRA_STRING_MAX_LEN is defined, named in keeping with the existing TIPC_TLV_ULTRA_STRING, and the various definitions in port, link and nametable code that largely duplicated this information are removed. This means that amount of link statistics that can be returned is now increased from 2k to 32k. The buffer overflow check is now done just before the reply message is passed over netlink or TIPC to a remote node and the message indicating a truncated buffer is changed to a less dramatic one (less CAPS), placed at the end of the message. Signed-off-by: Erik Hugne <erik.hugne@ericsson.com> Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2012-07-13tipc: simplify print buffer handling in tipc_printfErik Hugne
tipc_printf was previously used both to construct debug traces and to append data to buffers that should be sent over netlink to the tipc-config application. A global print_buffer was used to format the string before it was copied to the actual output buffer. This could lead to concurrent access of the global print_buffer, which then had to be lock protected. This is simplified by changing tipc_printf to append data directly to the output buffer using vscnprintf. With the new implementation of tipc_printf, there is no longer any risk of concurrent access to the internal log buffer, so the lock (and the comments describing it) are no longer strictly necessary. However, there are still a few functions that do grab this lock before resizing/dumping the log buffer. We leave the lock, and these functions untouched since they will be removed with a subsequent commit that drops the deprecated log buffer handling code Signed-off-by: Erik Hugne <erik.hugne@ericsson.com> Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2012-07-13tipc: simplify link_print by divorcing it from using tipc_printfPaul Gortmaker
To pave the way for a pending cleanup of tipc_printf, and removal of struct print_buf entirely, we make that task simpler by converting link_print to issue its messages with standard printk infrastructure. [Original idea separated from a larger patch from Erik Hugne <erik.hugne@ericsson.com>] Cc: Erik Hugne <erik.hugne@ericsson.com> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2012-07-13tipc: remove TIPC packet debugging functions and macrosErik Hugne
The link queue traces and packet level debug functions served a purpose during early development, but are now redundant since there are other, more capable tools available for debugging at the packet level. The TIPC_DEBUG Kconfig option is removed since it does not provide any extra debugging features anymore. This gets rid of a lot of tipc_printf usages, which will make the pending cleanup work of that function easier. Signed-off-by: Erik Hugne <erik.hugne@ericsson.com> Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2012-07-13tipc: use standard printk shortcut macros (pr_err etc.)Erik Hugne
All messages should go directly to the kernel log. The TIPC specific error, warning, info and debug trace macro's are removed and all references replaced with pr_err, pr_warn, pr_info and pr_debug. Commonly used sub-strings are explicitly declared as a const char to reduce .text size. Note that this means the debug messages (changed to pr_debug), are now enabled through dynamic debugging, instead of a TIPC specific Kconfig option (TIPC_DEBUG). The latter will be phased out completely Signed-off-by: Erik Hugne <erik.hugne@ericsson.com> Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> [PG: use pr_fmt as suggested by Joe Perches <joe@perches.com>] Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2012-07-12tipc: limit error messages relating to memory leak to one linePaul Gortmaker
With the default name table size of 1024, it is possible that the sanity check in tipc_nametbl_stop could spam out 1024 essentially identical error messages if memory was corrupted or similar. Limit it to issuing no more than a single message. The actual chain number (i.e. 0 --> 1023) wouldn't provide any useful insight if/when such an instance happened, so don't bother printing out that value. Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2012-07-12tipc: factor stats struct out of the larger link structPaul Gortmaker
This is done to improve readability, and so that we can give the struct a name that will allow us to declare a local pointer to it in code, instead of having to always redirect through the link struct to get to it. Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2012-07-11net: Fix non-kernel-doc comments with kernel-doc start markerBen Hutchings
Signed-off-by: Ben Hutchings <bhutchings@solarflare.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2012-07-11net: Fix (nearly-)kernel-doc comments for various functionsBen Hutchings
Fix incorrect start markers, wrapped summary lines, missing section breaks, incorrect separators, and some name mismatches. Signed-off-by: Ben Hutchings <bhutchings@solarflare.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2012-06-04net: Remove casts to same typeJoe Perches
Adding casts of objects to the same type is unnecessary and confusing for a human reader. For example, this cast: int y; int *p = (int *)&y; I used the coccinelle script below to find and remove these unnecessary casts. I manually removed the conversions this script produces of casts with __force and __user. @@ type T; T *p; @@ - (T *)p + p Signed-off-by: Joe Perches <joe@perches.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2012-04-30tipc: compress out gratuitous extra carriage returnsPaul Gortmaker
Some of the comment blocks are floating in limbo between two functions, or between blocks of code. Delete the extra line feeds between any comment and its associated following block of code, to be consistent with the majority of the rest of the kernel. Also delete trailing newlines at EOF and fix a couple trivial typos in existing comments. This is a 100% cosmetic change with no runtime impact. We get rid of over 500 lines of non-code, and being blank line deletes, they won't even show up as noise in git blame. Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2012-04-27tipc: Reject payload messages with invalid message typeAllan Stephens
Adds check to ensure TIPC sockets reject incoming payload messages that have an unrecognized message type. Remove the old open question about whether TIPC_ERR_NO_PORT is the proper return value. It is appropriate here since there are valid instances where another node can make use of the reply, and at this point in time the host is already broadcasting TIPC data, so there are no real security concerns. Signed-off-by: Allan Stephens <allan.stephens@windriver.com> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2012-04-26tipc: Enhance error checking of published namesAllan Stephens
Consolidates validation of scope and name sequence range values into a single routine where it applies both to local name publications and to name publications issued by other nodes in the network. This change means that the scope value for non-local publications is now validated and the name sequence range for local publications is now validated only once. Additionally, a publication attempt that fails validation now creates an entry in the system log file only if debugging capabilities have been enabled; this prevents the system log from being cluttered up with messages caused by a defective application or network node. Signed-off-by: Allan Stephens <allan.stephens@windriver.com> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2012-04-26tipc: Create helper routine to delete unused name sequence structureAllan Stephens
Replaces two identical chunks of code that delete an unused name sequence structure from TIPC's name table with calls to a new routine that performs this operation. This change is cosmetic and doesn't impact the operation of TIPC. Signed-off-by: Allan Stephens <allan.stephens@windriver.com> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2012-04-26tipc: remove redundant memset and stale comment from subscr.cAllan Stephens
Eliminate code to zero-out the main topology service structure, which is already zeroed-out. Get rid of a comment documenting a field of the main topology service structure that no longer exists. Both are cosmetic changes with no impact on runtime behaviour. Signed-off-by: Allan Stephens <allan.stephens@windriver.com> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2012-04-26tipc: Optimize initialization of network topology serviceAllan Stephens
Initialization now occurs in the calling thread of control, rather than being deferred to the TIPC tasklet. With the current codebase, the deferral is no longer necessary. Signed-off-by: Allan Stephens <allan.stephens@windriver.com> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2012-04-26tipc: Enhance re-initialization of network topology serviceAllan Stephens
Streamlines the job of re-initializing TIPC's network topology service when a node's network address is first assigned. Rather than destroying the topology server port and breaking its connections to existing subscribers, TIPC now simply lets the service continue running (since the change to the port identifier of each port used by the topology service no longer impacts the flow of messages between the service and its subscribers). This enhancement means that applications that utilize the topology service prior to the assignment of TIPC's network address no longer need to re-establish their subscriptions when the address is finally assigned. However, it is worth noting that any subsequent events for existing subscriptions report the new port identifier of the publishing port, rather than the original port identifier. (For example, a name that was previously reported as being published by <0.0.0:ref> may be subsequently withdrawn by <Z.C.N:ref>.) This doesn't impact any of the existing known userspace in tipc-utils, since (a) TIPC continues to treat references to the original port ID correctly and (b) normal use cases assign an address before active use. However if there does happen to be some rare/custom application out there that was relying on this, they can simply bypass the enhancement by issuing a subscription to {0,0} and break its connection to the topology service, if an associated withdrawal event occurs. Signed-off-by: Allan Stephens <allan.stephens@windriver.com> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2012-04-26tipc: Optimize termination of configuration serviceAllan Stephens
Termination no longer tests to see if the configuration service port was successfully created or not. In the unlikely event that the port was not created, attempting to delete the non-existent port is detected gracefully and causes no harm. Signed-off-by: Allan Stephens <allan.stephens@windriver.com> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>