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* tipc: clean up skb list lock handling on send pathJon Maloy2019-08-181-5/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The policy for handling the skb list locks on the send and receive paths is simple. - On the send path we never need to grab the lock on the 'xmitq' list when the destination is an exernal node. - On the receive path we always need to grab the lock on the 'inputq' list, irrespective of source node. However, when transmitting node local messages those will eventually end up on the receive path of a local socket, meaning that the argument 'xmitq' in tipc_node_xmit() will become the 'ínputq' argument in the function tipc_sk_rcv(). This has been handled by always initializing the spinlock of the 'xmitq' list at message creation, just in case it may end up on the receive path later, and despite knowing that the lock in most cases never will be used. This approach is inaccurate and confusing, and has also concealed the fact that the stated 'no lock grabbing' policy for the send path is violated in some cases. We now clean up this by never initializing the lock at message creation, instead doing this at the moment we find that the message actually will enter the receive path. At the same time we fix the four locations where we incorrectly access the spinlock on the send/error path. This patch also reverts commit d12cffe9329f ("tipc: ensure head->lock is initialised") which has now become redundant. CC: Eric Dumazet <edumazet@google.com> Reported-by: Chris Packham <chris.packham@alliedtelesis.co.nz> Acked-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Reviewed-by: Xin Long <lucien.xin@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* tipc: add loopback device trackingJohn Rutherford2019-08-081-1/+3
| | | | | | | | | | | | | | | | | | | | | Since node internal messages are passed directly to the socket, it is not possible to observe those messages via tcpdump or wireshark. We now remedy this by making it possible to clone such messages and send the clones to the loopback interface. The clones are dropped at reception and have no functional role except making the traffic visible. The feature is enabled if network taps are active for the loopback device. pcap filtering restrictions require the messages to be presented to the receiving side of the loopback device. v3 - Function dev_nit_active used to check for network taps. - Procedure netif_rx_ni used to send cloned messages to loopback device. Signed-off-by: John Rutherford <john.rutherford@dektech.com.au> Acked-by: Jon Maloy <jon.maloy@ericsson.com> Acked-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* tipc: rename function msg_get_wrapped() to msg_inner_hdr()Jon Maloy2019-06-251-2/+2
| | | | | | | | We rename the inline function msg_get_wrapped() to the more comprehensible msg_inner_hdr(). Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* tipc: add NULL pointer checkHoang Le2019-04-041-0/+3
| | | | | | | | | | | | | | skb somehow dequeued out of inputq before processing, it causes to NULL pointer and kernel crashed. Add checking skb valid before using. Fixes: c55c8edafa9 ("tipc: smooth change between replicast and broadcast") Reported-by: Tuong Lien Tong <tuong.t.lien@dektech.com.au> Acked-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: Hoang Le <hoang.h.le@dektech.com.au> Acked-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* tipc: fix return value check in tipc_mcast_send_sync()Wei Yongjun2019-03-261-1/+1
| | | | | | | | | | | Fix the return value check which testing the wrong variable in tipc_mcast_send_sync(). Fixes: c55c8edafa91 ("tipc: smooth change between replicast and broadcast") Reported-by: Hulk Robot <hulkci@huawei.com> Signed-off-by: Wei Yongjun <weiyongjun1@huawei.com> Acked-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* tipc: fix a null pointer derefHoang Le2019-03-211-1/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | In commit c55c8edafa91 ("tipc: smooth change between replicast and broadcast") we introduced new method to eliminate the risk of message reordering that happen in between different nodes. Unfortunately, we forgot checking at receiving side to ignore intra node. We fix this by checking and returning if arrived message from intra node. syzbot report: ================================================================== kasan: CONFIG_KASAN_INLINE enabled kasan: GPF could be caused by NULL-ptr deref or user memory access general protection fault: 0000 [#1] PREEMPT SMP KASAN CPU: 0 PID: 7820 Comm: syz-executor418 Not tainted 5.0.0+ #61 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:tipc_mcast_filter_msg+0x21b/0x13d0 net/tipc/bcast.c:782 Code: 45 c0 0f 84 39 06 00 00 48 89 5d 98 e8 ce ab a5 fa 49 8d bc 24 c8 00 00 00 48 b9 00 00 00 00 00 fc ff df 48 89 f8 48 c1 e8 03 <80> 3c 08 00 0f 85 9a 0e 00 00 49 8b 9c 24 c8 00 00 00 48 be 00 00 RSP: 0018:ffff8880959defc8 EFLAGS: 00010202 RAX: 0000000000000019 RBX: ffff888081258a48 RCX: dffffc0000000000 RDX: 0000000000000000 RSI: ffffffff86cab862 RDI: 00000000000000c8 RBP: ffff8880959df030 R08: ffff8880813d0200 R09: ffffed1015d05bc8 R10: ffffed1015d05bc7 R11: ffff8880ae82de3b R12: 0000000000000000 R13: 000000000000002c R14: 0000000000000000 R15: ffff888081258a48 FS: 000000000106a880(0000) GS:ffff8880ae800000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000020001cc0 CR3: 0000000094a20000 CR4: 00000000001406f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: tipc_sk_filter_rcv+0x182d/0x34f0 net/tipc/socket.c:2168 tipc_sk_enqueue net/tipc/socket.c:2254 [inline] tipc_sk_rcv+0xc45/0x25a0 net/tipc/socket.c:2305 tipc_sk_mcast_rcv+0x724/0x1020 net/tipc/socket.c:1209 tipc_mcast_xmit+0x7fe/0x1200 net/tipc/bcast.c:410 tipc_sendmcast+0xb36/0xfc0 net/tipc/socket.c:820 __tipc_sendmsg+0x10df/0x18d0 net/tipc/socket.c:1358 tipc_sendmsg+0x53/0x80 net/tipc/socket.c:1291 sock_sendmsg_nosec net/socket.c:651 [inline] sock_sendmsg+0xdd/0x130 net/socket.c:661 ___sys_sendmsg+0x806/0x930 net/socket.c:2260 __sys_sendmsg+0x105/0x1d0 net/socket.c:2298 __do_sys_sendmsg net/socket.c:2307 [inline] __se_sys_sendmsg net/socket.c:2305 [inline] __x64_sys_sendmsg+0x78/0xb0 net/socket.c:2305 do_syscall_64+0x103/0x610 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x4401c9 Code: 18 89 d0 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 fb 13 fc ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007ffd887fa9d8 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 00000000004002c8 RCX: 00000000004401c9 RDX: 0000000000000000 RSI: 0000000020002140 RDI: 0000000000000003 RBP: 00000000006ca018 R08: 0000000000000000 R09: 00000000004002c8 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000401a50 R13: 0000000000401ae0 R14: 0000000000000000 R15: 0000000000000000 Modules linked in: ---[ end trace ba79875754e1708f ]--- Reported-by: syzbot+be4bdf2cc3e85e952c50@syzkaller.appspotmail.com Fixes: c55c8eda ("tipc: smooth change between replicast and broadcast") Acked-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: Hoang Le <hoang.h.le@dektech.com.au> Signed-off-by: David S. Miller <davem@davemloft.net>
* tipc: smooth change between replicast and broadcastHoang Le2019-03-191-1/+164
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Currently, a multicast stream may start out using replicast, because there are few destinations, and then it should ideally switch to L2/broadcast IGMP/multicast when the number of destinations grows beyond a certain limit. The opposite should happen when the number decreases below the limit. To eliminate the risk of message reordering caused by method change, a sending socket must stick to a previously selected method until it enters an idle period of 5 seconds. Means there is a 5 seconds pause in the traffic from the sender socket. If the sender never makes such a pause, the method will never change, and transmission may become very inefficient as the cluster grows. With this commit, we allow such a switch between replicast and broadcast without any need for a traffic pause. Solution is to send a dummy message with only the header, also with the SYN bit set, via broadcast or replicast. For the data message, the SYN bit is set and sending via replicast or broadcast (inverse method with dummy). Then, at receiving side any messages follow first SYN bit message (data or dummy message), they will be held in deferred queue until another pair (dummy or data message) arrived in other link. v2: reverse christmas tree declaration Acked-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: Hoang Le <hoang.h.le@dektech.com.au> Signed-off-by: David S. Miller <davem@davemloft.net>
* tipc: support broadcast/replicast configurable for bc-linkHoang Le2019-03-191-4/+100
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Currently, a multicast stream uses either broadcast or replicast as transmission method, based on the ratio between number of actual destinations nodes and cluster size. However, when an L2 interface (e.g., VXLAN) provides pseudo broadcast support, this becomes very inefficient, as it blindly replicates multicast packets to all cluster/subnet nodes, irrespective of whether they host actual target sockets or not. The TIPC multicast algorithm is able to distinguish real destination nodes from other nodes, and hence provides a smarter and more efficient method for transferring multicast messages than pseudo broadcast can do. Because of this, we now make it possible for users to force the broadcast link to permanently switch to using replicast, irrespective of which capabilities the bearer provides, or pretend to provide. Conversely, we also make it possible to force the broadcast link to always use true broadcast. While maybe less useful in deployed systems, this may at least be useful for testing the broadcast algorithm in small clusters. We retain the current AUTOSELECT ability, i.e., to let the broadcast link automatically select which algorithm to use, and to switch back and forth between broadcast and replicast as the ratio between destination node number and cluster size changes. This remains the default method. Furthermore, we make it possible to configure the threshold ratio for such switches. The default ratio is now set to 10%, down from 25% in the earlier implementation. Acked-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: Hoang Le <hoang.h.le@dektech.com.au> Signed-off-by: David S. Miller <davem@davemloft.net>
* tipc: correct spelling errors for struct tipc_bc_base's commentZhenbo Gao2018-09-031-2/+2
| | | | | | | | Trivial fix for two spelling mistakes. Signed-off-by: Zhenbo Gao <zhenbo.gao@windriver.com> Reviewed-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* net: tipc: bcast: Replace GFP_ATOMIC with GFP_KERNEL in tipc_bcast_init()Jia-Ju Bai2018-07-271-1/+1
| | | | | | | | | | | tipc_bcast_init() is never called in atomic context. It calls kzalloc() with GFP_ATOMIC, which is not necessary. GFP_ATOMIC can be replaced with GFP_KERNEL. This is found by a static analysis tool named DCNS written by myself. Signed-off-by: Jia-Ju Bai <baijiaju1990@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* tipc: bcast: use true and false for boolean valuesGustavo A. R. Silva2018-03-071-1/+1
| | | | | | | | | | Assign true or false to boolean variables instead of an integer value. This issue was detected with the help of Coccinelle. Signed-off-by: Gustavo A. R. Silva <garsilva@embeddedor.com> Acked-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* tipc: fall back to smaller MTU if allocation of local send skb failsJon Maloy2017-12-011-4/+8
| | | | | | | | | | | | | | | | | | | | | | When sending node local messages the code is using an 'mtu' of 66060 bytes to avoid unnecessary fragmentation. During situations of low memory tipc_msg_build() may sometimes fail to allocate such large buffers, resulting in unnecessary send failures. This can easily be remedied by falling back to a smaller MTU, and then reassemble the buffer chain as if the message were arriving from a remote node. At the same time, we change the initial MTU setting of the broadcast link to a lower value, so that large messages always are fragmented into smaller buffers even when we run in single node mode. Apart from obtaining the same advantage as for the 'fallback' solution above, this turns out to give a significant performance improvement. This can probably be explained with the __pskb_copy() operation performed on the buffer for each recipient during reception. We found the optimal value for this, considering the most relevant skb pool, to be 3744 bytes. Acked-by: Ying Xue <ying.xue@ericsson.com> Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* tipc: improve destination linked listJon Maloy2017-10-131-9/+9
| | | | | | | | | | | | We often see a need for a linked list of destination identities, sometimes containing a port number, sometimes a node identity, and sometimes both. The currently defined struct u32_list is not generic enough to cover all cases, so we extend it to contain two u32 integers and rename it to struct tipc_dest_list. Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Acked-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* tipc: correct initialization of skb listJon Maloy2017-10-081-2/+2
| | | | | | | | | | | We change the initialization of the skb transmit buffer queues in the functions tipc_bcast_xmit() and tipc_rcast_xmit() to also initialize their spinlocks. This is needed because we may, during error conditions, need to call skb_queue_purge() on those queues further down the stack. Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* tipc: make replicast a user selectable optionJon Paul Maloy2017-01-201-6/+56
| | | | | | | | | | | | | | | | | | | | | | | | | | If the bearer carrying multicast messages supports broadcast, those messages will be sent to all cluster nodes, irrespective of whether these nodes host any actual destinations socket or not. This is clearly wasteful if the cluster is large and there are only a few real destinations for the message being sent. In this commit we extend the eligibility of the newly introduced "replicast" transmit option. We now make it possible for a user to select which method he wants to be used, either as a mandatory setting via setsockopt(), or as a relative setting where we let the broadcast layer decide which method to use based on the ratio between cluster size and the message's actual number of destination nodes. In the latter case, a sending socket must stick to a previously selected method until it enters an idle period of at least 5 seconds. This eliminates the risk of message reordering caused by method change, i.e., when changes to cluster size or number of destinations would otherwise mandate a new method to be used. Reviewed-by: Parthasarathy Bhuvaragan <parthasarathy.bhuvaragan@ericsson.com> Acked-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* tipc: introduce replicast as transport option for multicastJon Paul Maloy2017-01-201-23/+82
| | | | | | | | | | | | | | | | | | TIPC multicast messages are currently carried over a reliable 'broadcast link', making use of the underlying media's ability to transport packets as L2 broadcast or IP multicast to all nodes in the cluster. When the used bearer is lacking that ability, we can instead emulate the broadcast service by replicating and sending the packets over as many unicast links as needed to reach all identified destinations. We now introduce a new TIPC link-level 'replicast' service that does this. Reviewed-by: Parthasarathy Bhuvaragan <parthasarathy.bhuvaragan@ericsson.com> Acked-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* tipc: add functionality to lookup multicast destination nodesJon Paul Maloy2017-01-201-2/+31
| | | | | | | | | | | As a further preparation for the upcoming 'replicast' functionality, we add some necessary structs and functions for looking up and returning a list of all nodes that host destinations for a given multicast message. Reviewed-by: Parthasarathy Bhuvaragan <parthasarathy.bhuvaragan@ericsson.com> Acked-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* tipc: add function for checking broadcast support in bearerJon Paul Maloy2017-01-201-3/+9
| | | | | | | | | | | | | | | | | As a preparation for the 'replicast' functionality we are going to introduce in the next commits, we need the broadcast base structure to store whether bearer broadcast is available at all from the currently used bearer or bearers. We do this by adding a new function tipc_bearer_bcast_support() to the bearer layer, and letting the bearer selection function in bcast.c use this to give a new boolean field, 'bcast_support' the appropriate value. Reviewed-by: Parthasarathy Bhuvaragan <parthasarathy.bhuvaragan@ericsson.com> Acked-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* tipc: reduce risk of user starvation during link congestionJon Paul Maloy2017-01-031-3/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The socket code currently handles link congestion by either blocking and trying to send again when the congestion has abated, or just returning to the user with -EAGAIN and let him re-try later. This mechanism is prone to starvation, because the wakeup algorithm is non-atomic. During the time the link issues a wakeup signal, until the socket wakes up and re-attempts sending, other senders may have come in between and occupied the free buffer space in the link. This in turn may lead to a socket having to make many send attempts before it is successful. In extremely loaded systems we have observed latency times of several seconds before a low-priority socket is able to send out a message. In this commit, we simplify this mechanism and reduce the risk of the described scenario happening. When a message is attempted sent via a congested link, we now let it be added to the link's backlog queue anyway, thus permitting an oversubscription of one message per source socket. We still create a wakeup item and return an error code, hence instructing the sender to block or stop sending. Only when enough space has been freed up in the link's backlog queue do we issue a wakeup event that allows the sender to continue with the next message, if any. The fact that a socket now can consider a message sent even when the link returns a congestion code means that the sending socket code can be simplified. Also, since this is a good opportunity to get rid of the obsolete 'mtu change' condition in the three socket send functions, we now choose to refactor those functions completely. Signed-off-by: Parthasarathy Bhuvaragan <parthasarathy.bhuvaragan@ericsson.com> Acked-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* tipc: fix broadcast link synchronization problemJon Paul Maloy2016-10-291-4/+10
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | In commit 2d18ac4ba745 ("tipc: extend broadcast link initialization criteria") we tried to fix a problem with the initial synchronization of broadcast link acknowledge values. Unfortunately that solution is not sufficient to solve the issue. We have seen it happen that LINK_PROTOCOL/STATE packets with a valid non-zero unicast acknowledge number may bypass BCAST_PROTOCOL initialization, NAME_DISTRIBUTOR and other STATE packets with invalid broadcast acknowledge numbers, leading to premature opening of the broadcast link. When the bypassed packets finally arrive, they are inadvertently accepted, and the already correctly initialized acknowledge number in the broadcast receive link is overwritten by the invalid (zero) value of the said packets. After this the broadcast link goes stale. We now fix this by marking the packets where we know the acknowledge value is or may be invalid, and then ignoring the acks from those. To this purpose, we claim an unused bit in the header to indicate that the value is invalid. We set the bit to 1 in the initial BCAST_PROTOCOL synchronization packet and all initial ("bulk") NAME_DISTRIBUTOR packets, plus those LINK_PROTOCOL packets sent out before the broadcast links are fully synchronized. This minor protocol update is fully backwards compatible. Reported-by: John Thompson <thompa.atl@gmail.com> Tested-by: John Thompson <thompa.atl@gmail.com> Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* tipc: transfer broadcast nacks in link state messagesJon Paul Maloy2016-09-021-3/+5
| | | | | | | | | | | | | | | | | | | | | | | | When we send broadcasts in clusters of more 70-80 nodes, we sometimes see the broadcast link resetting because of an excessive number of retransmissions. This is caused by a combination of two factors: 1) A 'NACK crunch", where loss of broadcast packets is discovered and NACK'ed by several nodes simultaneously, leading to multiple redundant broadcast retransmissions. 2) The fact that the NACKS as such also are sent as broadcast, leading to excessive load and packet loss on the transmitting switch/bridge. This commit deals with the latter problem, by moving sending of broadcast nacks from the dedicated BCAST_PROTOCOL/NACK message type to regular unicast LINK_PROTOCOL/STATE messages. We allocate 10 unused bits in word 8 of the said message for this purpose, and introduce a new capability bit, TIPC_BCAST_STATE_NACK in order to keep the change backwards compatible. Reviewed-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* tipc: remove pre-allocated message header in link structJon Paul Maloy2016-03-061-5/+0
| | | | | | | | | | | | | | | | | Until now, we have kept a pre-allocated protocol message header aggregated into struct tipc_link. Apart from adding unnecessary footprint to the link instances, this requires extra code both to initialize and re-initialize it. We now remove this sub-optimization. This change also makes it possible to clean up the function tipc_build_proto_msg() and remove a couple of small functions that were accessing the mentioned header. In particular, we can replace all occurrences of the local function call link_own_addr(link) with the generic tipc_own_addr(net). Acked-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* tipc: narrow down interface towards struct tipc_linkJon Paul Maloy2015-11-201-122/+4
| | | | | | | | | | | | | | We move the definition of struct tipc_link from link.h to link.c in order to minimize its exposure to the rest of the code. When needed, we define new functions to make it possible for external entities to access and set data in the link. Apart from the above, there are no functional changes. Reviewed-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* tipc: clean up unused code and structuresJon Paul Maloy2015-10-241-798/+17
| | | | | | | | | | | | After the previous changes in this series, we can now remove some unused code and structures, both in the broadcast, link aggregation and link code. There are no functional changes in this commit. Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Reviewed-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* tipc: eliminate link's reference to owner nodeJon Paul Maloy2015-10-241-1/+1
| | | | | | | | | | | | | | | | With the recent commit series, we have established a one-way dependency between the link aggregation (struct tipc_node) instances and their pertaining tipc_link instances. This has enabled quite significant code and structure simplifications. In this commit, we eliminate the field 'owner', which points to an instance of struct tipc_node, from struct tipc_link, and replace it with a pointer to struct net, which is the only external reference now needed by a link instance. Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Reviewed-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* tipc: introduce jumbo frame support for broadcastJon Paul Maloy2015-10-241-4/+11
| | | | | | | | | | | | | Until now, we have only been supporting a fix MTU size of 1500 bytes for all broadcast media, irrespective of their actual capability. We now make the broadcast MTU adaptable to the carrying media, i.e., we use the smallest MTU supported by any of the interfaces attached to TIPC. Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Reviewed-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* tipc: simplify bearer level broadcastJon Paul Maloy2015-10-241-33/+110
| | | | | | | | | | | | | | | | | | | | | | | | | | | | Until now, we have been keeping track of the exact set of broadcast destinations though the help structure tipc_node_map. This leads us to have to maintain a whole infrastructure for supporting this, including a pseudo-bearer and a number of functions to manipulate both the bearers and the node map correctly. Apart from the complexity, this approach is also limiting, as struct tipc_node_map only can support cluster local broadcast if we want to avoid it becoming excessively large. We want to eliminate this limitation, in order to enable introduction of scoped multicast in the future. A closer analysis reveals that it is unnecessary maintaining this "full set" overview; it is sufficient to keep a counter per bearer, indicating how many nodes can be reached via this bearer at the moment. The protocol is now robust enough to handle transitional discrepancies between the nominal number of reachable destinations, as expected by the broadcast protocol itself, and the number which is actually reachable at the moment. The initial broadcast synchronization, in conjunction with the retransmission mechanism, ensures that all packets will eventually be acknowledged by the correct set of destinations. This commit introduces these changes. Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Reviewed-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* tipc: let broadcast packet reception use new link receive functionJon Paul Maloy2015-10-241-31/+132
| | | | | | | | | | | | | | | | | | | | | | The code path for receiving broadcast packets is currently distinct from the unicast path. This leads to unnecessary code and data duplication, something that can be avoided with some effort. We now introduce separate per-peer tipc_link instances for handling broadcast packet reception. Each receive link keeps a pointer to the common, single, broadcast link instance, and can hence handle release and retransmission of send buffers as if they belonged to the own instance. Furthermore, we let each unicast link instance keep a reference to both the pertaining broadcast receive link, and to the common send link. This makes it possible for the unicast links to easily access data for broadcast link synchronization, as well as for carrying acknowledges for received broadcast packets. Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Reviewed-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* tipc: introduce capability bit for broadcast synchronizationJon Paul Maloy2015-10-241-0/+1
| | | | | | | | | | | | | | | | | Until now, we have tried to support both the newer, dedicated broadcast synchronization mechanism along with the older, less safe, RESET_MSG/ ACTIVATE_MSG based one. The latter method has turned out to be a hazard in a highly dynamic cluster, so we find it safer to disable it completely when we find that the former mechanism is supported by the peer node. For this purpose, we now introduce a new capabability bit, TIPC_BCAST_SYNCH, to inform any peer nodes that dedicated broadcast syncronization is supported by the present node. The new bit is conveyed between peers in the 'capabilities' field of neighbor discovery messages. Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Reviewed-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* tipc: let broadcast transmission use new link transmit functionJon Paul Maloy2015-10-241-47/+51
| | | | | | | | | | This commit simplifies the broadcast link transmission function, by leveraging previous changes to the link transmission function and the broadcast transmission link life cycle. Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Reviewed-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* tipc: use explicit allocation of broadcast send linkJon Paul Maloy2015-10-241-43/+46
| | | | | | | | | | | | | | | | | The broadcast link instance (struct tipc_link) used for sending is currently aggregated into struct tipc_bclink. This means that we cannot use the regular tipc_link_create() function for initiating the link, but do instead have to initiate numerous fields directly from the bcast_init() function. We want to reduce dependencies between the broadcast functionality and the inner workings of tipc_link. In this commit, we introduce a new function tipc_bclink_create() to link.c, and allocate the instance of the link separately using this function. Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Reviewed-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* tipc: create broadcast transmission link at namespace initJon Paul Maloy2015-10-241-2/+13
| | | | | | | | | | | | | | | | | | | The broadcast transmission link is currently instantiated when the network subsystem is started, i.e., on order from user space via netlink. This forces the broadcast transmission code to do unnecessary tests for the existence of the transmission link, as well in single mode node as in network mode. In this commit, we do instead create the link during initialization of the name space, and remove it when it is stopped. The fact that the transmission link now has a guaranteed longer life cycle than any of its potential clients paves the way for further code simplifcations and optimizations. Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Reviewed-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* tipc: move broadcast link lock to struct tipc_netJon Paul Maloy2015-10-241-9/+3
| | | | | | | | | | | | | The broadcast lock will need to be acquired outside bcast.c in a later commit. For this reason, we move the lock to struct tipc_net. Consistent with the changes in the previous commit, we also introducee two new functions tipc_bcast_lock() and tipc_bcast_unlock(). The code that is currently using tipc_bclink_lock()/unlock() will be phased out during the coming commits in this series. Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Reviewed-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* tipc: move bcast definitions to bcast.cJon Paul Maloy2015-10-241-24/+93
| | | | | | | | | | | | | | | | | | | | | | | | | | | | Currently, a number of structure and function definitions related to the broadcast functionality are unnecessarily exposed in the file bcast.h. This obscures the fact that the external interface towards the broadcast link in fact is very narrow, and causes unnecessary recompilations of other files when anything changes in those definitions. In this commit, we move as many of those definitions as is currently possible to the file bcast.c. We also rename the structure 'tipc_bclink' to 'tipc_bc_base', both since the name does not correctly describe the contents of this struct, and will do so even less in the future, and because we want to use the term 'link' more appropriately in the functionality introduced later in this series. Finally, we rename a couple of functions, such as tipc_bclink_xmit() and others that will be kept in the future, to include the term 'bcast' instead. There are no functional changes in this commit. Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Reviewed-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* tipc: extend broadcast link window sizeJon Paul Maloy2015-10-211-3/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The default fix broadcast window size is currently set to 20 packets. This is a very low value, set at a time when we were still testing on 10 Mb/s hubs, and a change to it is long overdue. Commit 7845989cb4b3da1db ("net: tipc: fix stall during bclink wakeup procedure") revealed a problem with this low value. For messages of importance LOW, the backlog queue limit will be calculated to 30 packets, while a single, maximum sized message of 66000 bytes, carried across a 1500 MTU network consists of 46 packets. This leads to the following scenario (among others leading to the same situation): 1: Msg 1 of 46 packets is sent. 20 packets go to the transmit queue, 26 packets to the backlog queue. 2: Msg 2 of 46 packets is attempted sent, but rejected because there is no more space in the backlog queue at this level. The sender is added to the wakeup queue with a "pending packets chain size" number of 46. 3: Some packets in the transmit queue are acked and released. We try to wake up the sender, but the pending size of 46 is bigger than the LOW wakeup limit of 30, so this doesn't happen. 5: Subsequent acks releases all the remaining buffers. Each time we test for the wakeup criteria and find that 46 still is larger than 30, even after both the transmit and the backlog queues are empty. 6: The sender is never woken up and given a chance to send its message. He is stuck. We could now loosen the wakeup criteria (used by link_prepare_wakeup()) to become equal to the send criteria (used by tipc_link_xmit()), i.e., by ignoring the "pending packets chain size" value altogether, or we can just increase the queue limits so that the criteria can be satisfied anyway. There are good reasons (potentially multiple waiting senders) to not opt for the former solution, so we choose the latter one. This commit fixes the problem by giving the broadcast link window a default value of 50 packets. We also introduce a new minimum link window size BCLINK_MIN_WIN of 32, which is enough to always avoid the described situation. Finally, in order to not break any existing users which may set the window explicitly, we enforce that the window is set to the new minimum value in case the user is trying to set it to anything lower. Fixes: 7845989cb4b3da1db ("net: tipc: fix stall during bclink wakeup procedure") Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Reviewed-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* net: tipc: fix stall during bclink wakeup procedureKolmakov Dmitriy2015-09-081-1/+29
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | If an attempt to wake up users of broadcast link is made when there is no enough place in send queue than it may hang up inside the tipc_sk_rcv() function since the loop breaks only after the wake up queue becomes empty. This can lead to complete CPU stall with the following message generated by RCU: INFO: rcu_sched self-detected stall on CPU { 0} (t=2101 jiffies g=54225 c=54224 q=11465) Task dump for CPU 0: tpch R running task 0 39949 39948 0x0000000a ffffffff818536c0 ffff88181fa037a0 ffffffff8106a4be 0000000000000000 ffffffff818536c0 ffff88181fa037c0 ffffffff8106d8a8 ffff88181fa03800 0000000000000001 ffff88181fa037f0 ffffffff81094a50 ffff88181fa15680 Call Trace: <IRQ> [<ffffffff8106a4be>] sched_show_task+0xae/0x120 [<ffffffff8106d8a8>] dump_cpu_task+0x38/0x40 [<ffffffff81094a50>] rcu_dump_cpu_stacks+0x90/0xd0 [<ffffffff81097c3b>] rcu_check_callbacks+0x3eb/0x6e0 [<ffffffff8106e53f>] ? account_system_time+0x7f/0x170 [<ffffffff81099e64>] update_process_times+0x34/0x60 [<ffffffff810a84d1>] tick_sched_handle.isra.18+0x31/0x40 [<ffffffff810a851c>] tick_sched_timer+0x3c/0x70 [<ffffffff8109a43d>] __run_hrtimer.isra.34+0x3d/0xc0 [<ffffffff8109aa95>] hrtimer_interrupt+0xc5/0x1e0 [<ffffffff81030d52>] ? native_smp_send_reschedule+0x42/0x60 [<ffffffff81032f04>] local_apic_timer_interrupt+0x34/0x60 [<ffffffff810335bc>] smp_apic_timer_interrupt+0x3c/0x60 [<ffffffff8165a3fb>] apic_timer_interrupt+0x6b/0x70 [<ffffffff81659129>] ? _raw_spin_unlock_irqrestore+0x9/0x10 [<ffffffff8107eb9f>] __wake_up_sync_key+0x4f/0x60 [<ffffffffa313ddd1>] tipc_write_space+0x31/0x40 [tipc] [<ffffffffa313dadf>] filter_rcv+0x31f/0x520 [tipc] [<ffffffffa313d699>] ? tipc_sk_lookup+0xc9/0x110 [tipc] [<ffffffff81659259>] ? _raw_spin_lock_bh+0x19/0x30 [<ffffffffa314122c>] tipc_sk_rcv+0x2dc/0x3e0 [tipc] [<ffffffffa312e7ff>] tipc_bclink_wakeup_users+0x2f/0x40 [tipc] [<ffffffffa313ce26>] tipc_node_unlock+0x186/0x190 [tipc] [<ffffffff81597c1c>] ? kfree_skb+0x2c/0x40 [<ffffffffa313475c>] tipc_rcv+0x2ac/0x8c0 [tipc] [<ffffffffa312ff58>] tipc_l2_rcv_msg+0x38/0x50 [tipc] [<ffffffff815a76d3>] __netif_receive_skb_core+0x5a3/0x950 [<ffffffff815a98d3>] __netif_receive_skb+0x13/0x60 [<ffffffff815a993e>] netif_receive_skb_internal+0x1e/0x90 [<ffffffff815aa138>] napi_gro_receive+0x78/0xa0 [<ffffffffa07f93f4>] tg3_poll_work+0xc54/0xf40 [tg3] [<ffffffff81597c8c>] ? consume_skb+0x2c/0x40 [<ffffffffa07f9721>] tg3_poll_msix+0x41/0x160 [tg3] [<ffffffff815ab0f2>] net_rx_action+0xe2/0x290 [<ffffffff8104b92a>] __do_softirq+0xda/0x1f0 [<ffffffff8104bc26>] irq_exit+0x76/0xa0 [<ffffffff81004355>] do_IRQ+0x55/0xf0 [<ffffffff8165a12b>] common_interrupt+0x6b/0x6b <EOI> The issue occurs only when tipc_sk_rcv() is used to wake up postponed senders: tipc_bclink_wakeup_users() // wakeupq - is a queue which consists of special // messages with SOCK_WAKEUP type. tipc_sk_rcv(wakeupq) ... while (skb_queue_len(inputq)) { filter_rcv(skb) // Here the type of message is checked // and if it is SOCK_WAKEUP then // it tries to wake up a sender. tipc_write_space(sk) wake_up_interruptible_sync_poll() } After the sender thread is woke up it can gather control and perform an attempt to send a message. But if there is no enough place in send queue it will call link_schedule_user() function which puts a message of type SOCK_WAKEUP to the wakeup queue and put the sender to sleep. Thus the size of the queue actually is not changed and the while() loop never exits. The approach I proposed is to wake up only senders for which there is enough place in send queue so the described issue can't occur. Moreover the same approach is already used to wake up senders on unicast links. I have got into the issue on our product code but to reproduce the issue I changed a benchmark test application (from tipcutils/demos/benchmark) to perform the following scenario: 1. Run 64 instances of test application (nodes). It can be done on the one physical machine. 2. Each application connects to all other using TIPC sockets in RDM mode. 3. When setup is done all nodes start simultaneously send broadcast messages. 4. Everything hangs up. The issue is reproducible only when a congestion on broadcast link occurs. For example, when there are only 8 nodes it works fine since congestion doesn't occur. Send queue limit is 40 in my case (I use a critical importance level) and when 64 nodes send a message at the same moment a congestion occurs every time. Signed-off-by: Dmitry S Kolmakov <kolmakov.dmitriy@huawei.com> Reviewed-by: Jon Maloy <jon.maloy@ericsson.com> Acked-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* tipc: reduce locking scope during packet receptionJon Paul Maloy2015-07-201-0/+23
| | | | | | | | | | | | | | | | | | | | | | | | | | We convert packet/message reception according to the same principle we have been using for message sending and timeout handling: We move the function tipc_rcv() to node.c, hence handling the initial packet reception at the link aggregation level. The function grabs the node lock, selects the receiving link, and accesses it via a new call tipc_link_rcv(). This function appends buffers to the input queue for delivery upwards, but it may also append outgoing packets to the xmit queue, just as we do during regular message sending. The latter will happen when buffers are forwarded from the link backlog, or when retransmission is requested. Upon return of this function, and after having released the node lock, tipc_rcv() delivers/tranmsits the contents of those queues, but it may also perform actions such as link activation or reset, as indicated by the return flags from the link. This reduces the number of cpu cycles spent inside the node spinlock, and reduces contention on that lock. Reviewed-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* tipc: clean up definitions and usage of link flagsJon Paul Maloy2015-07-201-1/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | The status flag LINK_STOPPED is not needed any more, since the mechanism for delayed deletion of links has been removed. Likewise, LINK_STARTED and LINK_START_EVT are unnecessary, because we can just as well start the link timer directly from inside tipc_link_create(). We eliminate these flags in this commit. Instead of the above flags, we now introduce three new link modes, TIPC_LINK_OPEN, TIPC_LINK_BLOCKED and TIPC_LINK_TUNNEL. The values indicate whether, and in the case of TIPC_LINK_TUNNEL, which, messages the link is allowed to receive in this state. TIPC_LINK_BLOCKED also blocks timer-driven protocol messages to be sent out, and any change to the link FSM. Since the modes are mutually exclusive, we convert them to state values, and rename the 'flags' field in struct tipc_link to 'exec_mode'. Finally, we move the #defines for link FSM states and events from link.h into enums inside the file link.c, which is the real usage scope of these definitions. Reviewed-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* tipc: change sk_buffer handling in tipc_link_xmit()Jon Paul Maloy2015-07-201-3/+2
| | | | | | | | | | | | | | | | | | | | When the function tipc_link_xmit() is given a buffer list for transmission, it currently consumes the list both when transmission is successful and when it fails, except for the special case when it encounters link congestion. This behavior is inconsistent, and needs to be corrected if we want to avoid problems in later commits in this series. In this commit, we change this to let the function consume the list only when transmission is successful, and leave the list with the sender in all other cases. We also modifiy the socket code so that it adapts to this change, i.e., purges the list when a non-congestion error code is returned. Reviewed-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* tipc: introduce link entry structure to struct tipc_nodeJon Paul Maloy2015-07-201-1/+1
| | | | | | | | | | | | | | | struct 'tipc_node' currently contains two arrays for link attributes, one for the link pointers, and one for the usable link MTUs. We now group those into a new struct 'tipc_link_entry', and intoduce one single array consisting of such enties. Apart from being a cosmetic improvement, this is a starting point for the strict master-slave relation between node and link that we will introduce in the following commits. Reviewed-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* tipc: purge backlog queue counters when broadcast link is resetJon Paul Maloy2015-06-281-0/+5
| | | | | | | | | | | | | | | | | | | | | | In commit 1f66d161ab3d8b518903fa6c3f9c1f48d6919e74 ("tipc: introduce starvation free send algorithm") we introduced a counter per priority level for buffers in the link backlog queue. We also introduced a new function tipc_link_purge_backlog(), to reset these counters to zero when the link is reset. Unfortunately, we missed to call this function when the broadcast link is reset, with the result that the values of these counters might be permanently skewed when new nodes are attached. This may in the worst case lead to permananent, but spurious, broadcast link congestion, where no broadcast packets can be sent at all. We fix this bug with this commit. Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* tipc: add packet sequence number at instant of transmissionJon Paul Maloy2015-05-141-5/+1
| | | | | | | | | | | | | | | | | | | | Currently, the packet sequence number is updated and added to each packet at the moment a packet is added to the link backlog queue. This is wasteful, since it forces the code to traverse the send packet list packet by packet when adding them to the backlog queue. It would be better to just splice the whole packet list into the backlog queue when that is the right action to do. In this commit, we do this change. Also, since the sequence numbers cannot now be assigned to the packets at the moment they are added the backlog queue, we do instead calculate and add them at the moment of transmission, when the backlog queue has to be traversed anyway. We do this in the function tipc_link_push_packet(). Reviewed-by: Erik Hugne <erik.hugne@ericsson.com> Reviewed-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* tipc: rename fields in struct tipc_linkJon Paul Maloy2015-05-141-9/+9
| | | | | | | | | | | | | | | | | | We rename some fields in struct tipc_link, in order to give them more descriptive names: next_in_no -> rcv_nxt next_out_no-> snd_nxt fsm_msg_cnt-> silent_intv_cnt cont_intv -> keepalive_intv last_retransmitted -> last_retransm There are no functional changes in this commit. Reviewed-by: Erik Hugne <erik.hugne@ericsson.com> Reviewed-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* tipc: add broadcast link window set/get to nl apiRichard Alpe2015-05-091-0/+21
| | | | | | | | | | | | | | Add the ability to get or set the broadcast link window through the new netlink API. The functionality was unintentionally missing from the new netlink API. Adding this means that we also fix the breakage in the old API when coming through the compat layer. Fixes: 37e2d4843f9e (tipc: convert legacy nl link prop set to nl compat) Reported-by: Tomi Ollila <tomi.ollila@iki.fi> Signed-off-by: Richard Alpe <richard.alpe@ericsson.com> Reviewed-by: Erik Hugne <erik.hugne@ericsson.com> Reviewed-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* tipc: simplify link mtu negotiationJon Paul Maloy2015-04-021-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | When a link is being established, the two endpoints advertise their respective interface MTU in the transmitted RESET and ACTIVATE messages. If there is any difference, the lower of the two MTUs will be selected for use by both endpoints. However, as a remnant of earlier attempts to introduce TIPC level routing. there also exists an MTU discovery mechanism. If an intermediate node has a lower MTU than the two endpoints, they will discover this through a bisectional approach, and finally adopt this MTU for common use. Since there is no TIPC level routing, and probably never will be, this mechanism doesn't make any sense, and only serves to make the link level protocol unecessarily complex. In this commit, we eliminate the MTU discovery algorithm,and fall back to the simple MTU advertising approach. This change is fully backwards compatible. Reviewed-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* tipc: involve reference counter for node structureYing Xue2015-03-291-2/+3
| | | | | | | | | | | | | | | | | | | | | TIPC node hash node table is protected with rcu lock on read side. tipc_node_find() is used to look for a node object with node address through iterating the hash node table. As the entire process of what tipc_node_find() traverses the table is guarded with rcu read lock, it's safe for us. However, when callers use the node object returned by tipc_node_find(), there is no rcu read lock applied. Therefore, this is absolutely unsafe for callers of tipc_node_find(). Now we introduce a reference counter for node structure. Before tipc_node_find() returns node object to its caller, it first increases the reference counter. Accordingly, after its caller used it up, it decreases the counter again. This can prevent a node being used by one thread from being freed by another thread. Reviewed-by: Erik Hugne <erik.hugne@ericsson.com> Reviewed-by: Jon Maloy <jon.maloy@ericson.com> Signed-off-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* tipc: fix potential deadlock when all links are resetYing Xue2015-03-291-22/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | [ 60.988363] ====================================================== [ 60.988754] [ INFO: possible circular locking dependency detected ] [ 60.989152] 3.19.0+ #194 Not tainted [ 60.989377] ------------------------------------------------------- [ 60.989781] swapper/3/0 is trying to acquire lock: [ 60.990079] (&(&n_ptr->lock)->rlock){+.-...}, at: [<ffffffffa0006dca>] tipc_link_retransmit+0x1aa/0x240 [tipc] [ 60.990743] [ 60.990743] but task is already holding lock: [ 60.991106] (&(&bclink->lock)->rlock){+.-...}, at: [<ffffffffa00004be>] tipc_bclink_lock+0x8e/0xa0 [tipc] [ 60.991738] [ 60.991738] which lock already depends on the new lock. [ 60.991738] [ 60.992174] [ 60.992174] the existing dependency chain (in reverse order) is: [ 60.992174] -> #1 (&(&bclink->lock)->rlock){+.-...}: [ 60.992174] [<ffffffff810a9c0c>] lock_acquire+0x9c/0x140 [ 60.992174] [<ffffffff8179c41f>] _raw_spin_lock_bh+0x3f/0x50 [ 60.992174] [<ffffffffa00004be>] tipc_bclink_lock+0x8e/0xa0 [tipc] [ 60.992174] [<ffffffffa0000f57>] tipc_bclink_add_node+0x97/0xf0 [tipc] [ 60.992174] [<ffffffffa0011815>] tipc_node_link_up+0xf5/0x110 [tipc] [ 60.992174] [<ffffffffa0007783>] link_state_event+0x2b3/0x4f0 [tipc] [ 60.992174] [<ffffffffa00193c0>] tipc_link_proto_rcv+0x24c/0x418 [tipc] [ 60.992174] [<ffffffffa0008857>] tipc_rcv+0x827/0xac0 [tipc] [ 60.992174] [<ffffffffa0002ca3>] tipc_l2_rcv_msg+0x73/0xd0 [tipc] [ 60.992174] [<ffffffff81646e66>] __netif_receive_skb_core+0x746/0x980 [ 60.992174] [<ffffffff816470c1>] __netif_receive_skb+0x21/0x70 [ 60.992174] [<ffffffff81647295>] netif_receive_skb_internal+0x35/0x130 [ 60.992174] [<ffffffff81648218>] napi_gro_receive+0x158/0x1d0 [ 60.992174] [<ffffffff81559e05>] e1000_clean_rx_irq+0x155/0x490 [ 60.992174] [<ffffffff8155c1b7>] e1000_clean+0x267/0x990 [ 60.992174] [<ffffffff81647b60>] net_rx_action+0x150/0x360 [ 60.992174] [<ffffffff8105ec43>] __do_softirq+0x123/0x360 [ 60.992174] [<ffffffff8105f12e>] irq_exit+0x8e/0xb0 [ 60.992174] [<ffffffff8179f9f5>] do_IRQ+0x65/0x110 [ 60.992174] [<ffffffff8179da6f>] ret_from_intr+0x0/0x13 [ 60.992174] [<ffffffff8100de9f>] arch_cpu_idle+0xf/0x20 [ 60.992174] [<ffffffff8109dfa6>] cpu_startup_entry+0x2f6/0x3f0 [ 60.992174] [<ffffffff81033cda>] start_secondary+0x13a/0x150 [ 60.992174] -> #0 (&(&n_ptr->lock)->rlock){+.-...}: [ 60.992174] [<ffffffff810a8f7d>] __lock_acquire+0x163d/0x1ca0 [ 60.992174] [<ffffffff810a9c0c>] lock_acquire+0x9c/0x140 [ 60.992174] [<ffffffff8179c41f>] _raw_spin_lock_bh+0x3f/0x50 [ 60.992174] [<ffffffffa0006dca>] tipc_link_retransmit+0x1aa/0x240 [tipc] [ 60.992174] [<ffffffffa0001e11>] tipc_bclink_rcv+0x611/0x640 [tipc] [ 60.992174] [<ffffffffa0008646>] tipc_rcv+0x616/0xac0 [tipc] [ 60.992174] [<ffffffffa0002ca3>] tipc_l2_rcv_msg+0x73/0xd0 [tipc] [ 60.992174] [<ffffffff81646e66>] __netif_receive_skb_core+0x746/0x980 [ 60.992174] [<ffffffff816470c1>] __netif_receive_skb+0x21/0x70 [ 60.992174] [<ffffffff81647295>] netif_receive_skb_internal+0x35/0x130 [ 60.992174] [<ffffffff81648218>] napi_gro_receive+0x158/0x1d0 [ 60.992174] [<ffffffff81559e05>] e1000_clean_rx_irq+0x155/0x490 [ 60.992174] [<ffffffff8155c1b7>] e1000_clean+0x267/0x990 [ 60.992174] [<ffffffff81647b60>] net_rx_action+0x150/0x360 [ 60.992174] [<ffffffff8105ec43>] __do_softirq+0x123/0x360 [ 60.992174] [<ffffffff8105f12e>] irq_exit+0x8e/0xb0 [ 60.992174] [<ffffffff8179f9f5>] do_IRQ+0x65/0x110 [ 60.992174] [<ffffffff8179da6f>] ret_from_intr+0x0/0x13 [ 60.992174] [<ffffffff8100de9f>] arch_cpu_idle+0xf/0x20 [ 60.992174] [<ffffffff8109dfa6>] cpu_startup_entry+0x2f6/0x3f0 [ 60.992174] [<ffffffff81033cda>] start_secondary+0x13a/0x150 [ 60.992174] [ 60.992174] other info that might help us debug this: [ 60.992174] [ 60.992174] Possible unsafe locking scenario: [ 60.992174] [ 60.992174] CPU0 CPU1 [ 60.992174] ---- ---- [ 60.992174] lock(&(&bclink->lock)->rlock); [ 60.992174] lock(&(&n_ptr->lock)->rlock); [ 60.992174] lock(&(&bclink->lock)->rlock); [ 60.992174] lock(&(&n_ptr->lock)->rlock); [ 60.992174] [ 60.992174] *** DEADLOCK *** [ 60.992174] [ 60.992174] 3 locks held by swapper/3/0: [ 60.992174] #0: (rcu_read_lock){......}, at: [<ffffffff81646791>] __netif_receive_skb_core+0x71/0x980 [ 60.992174] #1: (rcu_read_lock){......}, at: [<ffffffffa0002c35>] tipc_l2_rcv_msg+0x5/0xd0 [tipc] [ 60.992174] #2: (&(&bclink->lock)->rlock){+.-...}, at: [<ffffffffa00004be>] tipc_bclink_lock+0x8e/0xa0 [tipc] [ 60.992174] The correct the sequence of grabbing n_ptr->lock and bclink->lock should be that the former is first held and the latter is then taken, which exactly happened on CPU1. But especially when the retransmission of broadcast link is failed, bclink->lock is first held in tipc_bclink_rcv(), and n_ptr->lock is taken in link_retransmit_failure() called by tipc_link_retransmit() subsequently, which is demonstrated on CPU0. As a result, deadlock occurs. If the order of holding the two locks happening on CPU0 is reversed, the deadlock risk will be relieved. Therefore, the node lock taken in link_retransmit_failure() originally is moved to tipc_bclink_rcv() so that it's obtained before bclink lock. But the precondition of the adjustment of node lock is that responding to bclink reset event must be moved from tipc_bclink_unlock() to tipc_node_unlock(). Reviewed-by: Erik Hugne <erik.hugne@ericsson.com> Signed-off-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* tipc: introduce starvation free send algorithmJon Paul Maloy2015-03-251-1/+1
| | | | | | | | | | | | | | | | | | | | | | | Currently, we only use a single counter; the length of the backlog queue, to determine whether a message should be accepted to the queue or not. Each time a message is being sent, the queue length is compared to a threshold value for the message's importance priority. If the queue length is beyond this threshold, the message is rejected. This algorithm implies a risk of starvation of low importance senders during very high load, because it may take a long time before the backlog queue has decreased enough to accept a lower level message. We now eliminate this risk by introducing a counter for each importance priority. When a message is sent, we check only the queue level for that particular message's priority. If that is ok, the message can be added to the backlog, irrespective of the queue level for other priorities. This way, each level is guaranteed a certain portion of the total bandwidth, and any risk of starvation is eliminated. Reviewed-by: Ying Xue <ying.xue@windriver.com> Reviewed-by: Erik Hugne <erik.hugne@ericsson.com> Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* tipc: fix a link reset issue due to retransmission failuresYing Xue2015-03-251-3/+5
| | | | | | | | | | | | | | | When a node joins a cluster while we are transmitting a fragment stream over the broadcast link, it's missing the preceding fragments needed to build a meaningful message. As a result, the node has to drop it. However, as the fragment message is not acknowledged to its sender before it's dropped, it accidentally causes link reset of retransmission failure on the node. Reported-by: Erik Hugne <erik.hugne@ericsson.com> Signed-off-by: Ying Xue <ying.xue@windriver.com> Reviewed-by: Erik Hugne <erik.hugne@ericsson.com> Tested-by: Erik Hugne <erik.hugne@ericsson.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* tipc: clean up handling of message prioritiesJon Paul Maloy2015-03-141-1/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Messages transferred by TIPC are assigned an "importance priority", -an integer value indicating how to treat the message when there is link or destination socket congestion. There is no separate header field for this value. Instead, the message user values have been chosen in ascending order according to perceived importance, so that the message user field can be used for this. This is not a good solution. First, we have many more users than the needed priority levels, so we end up with treating more priority levels than necessary. Second, the user field cannot always accurately reflect the priority of the message. E.g., a message fragment packet should really have the priority of the enveloped user data message, and not the priority of the MSG_FRAGMENTER user. Until now, we have been working around this problem in different ways, but it is now time to implement a consistent way of handling such priorities, although still within the constraint that we cannot allocate any more bits in the regular data message header for this. In this commit, we define a new priority level, TIPC_SYSTEM_IMPORTANCE, that will be the only one used apart from the four (lower) user data levels. All non-data messages map down to this priority. Furthermore, we take some free bits from the MSG_FRAGMENTER header and allocate them to store the priority of the enveloped message. We then adjust the functions msg_importance()/msg_set_importance() so that they read/set the correct header fields depending on user type. This small protocol change is fully compatible, because the code at the receiving end of a link currently reads the importance level only from user data messages, where there is no change. Reviewed-by: Erik Hugne <erik.hugne@ericsson.com> Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: David S. Miller <davem@davemloft.net>
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