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2019-03-08rxrpc: Fix client call queueing, waiting for channelDavid Howells
rxrpc_get_client_conn() adds a new call to the front of the waiting_calls queue if the connection it's going to use already exists. This is bad as it allows calls to get starved out. Fix this by adding to the tail instead. Also change the other enqueue point in the same function to put it on the front (ie. when we have a new connection). This makes the point that in the case of a new connection the new call goes at the front (though it doesn't actually matter since the queue should be unoccupied). Fixes: 45025bceef17 ("rxrpc: Improve management and caching of client connection objects") Signed-off-by: David Howells <dhowells@redhat.com> Reviewed-by: Marc Dionne <marc.dionne@auristor.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2019-03-08rxrpc: Fix client call connect/disconnect raceDavid Howells
rxrpc_disconnect_client_call() reads the call's connection ID protocol value (call->cid) as part of that function's variable declarations. This is bad because it's not inside the locked section and so may race with someone granting use of the channel to the call. This manifests as an assertion failure (see below) where the call in the presumed channel (0 because call->cid wasn't set when we read it) doesn't match the call attached to the channel we were actually granted (if 1, 2 or 3). Fix this by moving the read and dependent calculations inside of the channel_lock section. Also, only set the channel number and pointer variables if cid is not zero (ie. unset). This problem can be induced by injecting an occasional error in rxrpc_wait_for_channel() before the call to schedule(). Make two further changes also: (1) Add a trace for wait failure in rxrpc_connect_call(). (2) Drop channel_lock before BUG'ing in the case of the assertion failure. The failure causes a trace akin to the following: rxrpc: Assertion failed - 18446612685268945920(0xffff8880beab8c00) == 18446612685268621312(0xffff8880bea69800) is false ------------[ cut here ]------------ kernel BUG at net/rxrpc/conn_client.c:824! ... RIP: 0010:rxrpc_disconnect_client_call+0x2bf/0x99d ... Call Trace: rxrpc_connect_call+0x902/0x9b3 ? wake_up_q+0x54/0x54 rxrpc_new_client_call+0x3a0/0x751 ? rxrpc_kernel_begin_call+0x141/0x1bc ? afs_alloc_call+0x1b5/0x1b5 rxrpc_kernel_begin_call+0x141/0x1bc afs_make_call+0x20c/0x525 ? afs_alloc_call+0x1b5/0x1b5 ? __lock_is_held+0x40/0x71 ? lockdep_init_map+0xaf/0x193 ? lockdep_init_map+0xaf/0x193 ? __lock_is_held+0x40/0x71 ? yfs_fs_fetch_data+0x33b/0x34a yfs_fs_fetch_data+0x33b/0x34a afs_fetch_data+0xdc/0x3b7 afs_read_dir+0x52d/0x97f afs_dir_iterate+0xa0/0x661 ? iterate_dir+0x63/0x141 iterate_dir+0xa2/0x141 ksys_getdents64+0x9f/0x11b ? filldir+0x111/0x111 ? do_syscall_64+0x3e/0x1a0 __x64_sys_getdents64+0x16/0x19 do_syscall_64+0x7d/0x1a0 entry_SYSCALL_64_after_hwframe+0x49/0xbe Fixes: 45025bceef17 ("rxrpc: Improve management and caching of client connection objects") Signed-off-by: David Howells <dhowells@redhat.com> Reviewed-by: Marc Dionne <marc.dionne@auristor.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2019-01-15Revert "rxrpc: Allow failed client calls to be retried"David Howells
The changes introduced to allow rxrpc calls to be retried creates an issue when it comes to refcounting afs_call structs. The problem is that when rxrpc_send_data() queues the last packet for an asynchronous call, the following sequence can occur: (1) The notify_end_tx callback is invoked which causes the state in the afs_call to be changed from AFS_CALL_CL_REQUESTING or AFS_CALL_SV_REPLYING. (2) afs_deliver_to_call() can then process event notifications from rxrpc on the async_work queue. (3) Delivery of events, such as an abort from the server, can cause the afs_call state to be changed to AFS_CALL_COMPLETE on async_work. (4) For an asynchronous call, afs_process_async_call() notes that the call is complete and tried to clean up all the refs on async_work. (5) rxrpc_send_data() might return the amount of data transferred (success) or an error - which could in turn reflect a local error or a received error. Synchronising the clean up after rxrpc_kernel_send_data() returns an error with the asynchronous cleanup is then tricky to get right. Mostly revert commit c038a58ccfd6704d4d7d60ed3d6a0fca13cf13a4. The two API functions the original commit added aren't currently used. This makes rxrpc_kernel_send_data() always return successfully if it queued the data it was given. Note that this doesn't affect synchronous calls since their Rx notification function merely pokes a wait queue and does not refcounting. The asynchronous call notification function *has* to do refcounting and pass a ref over the work item to avoid the need to sync the workqueue in call cleanup. Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-10-05rxrpc: Fix some missed refs to init_netDavid Howells
Fix some refs to init_net that should've been changed to the appropriate network namespace. Fixes: 2baec2c3f854 ("rxrpc: Support network namespacing") Signed-off-by: David Howells <dhowells@redhat.com> Acked-by: Paolo Abeni <pabeni@redhat.com>
2018-09-28rxrpc: Fix error distributionDavid Howells
Fix error distribution by immediately delivering the errors to all the affected calls rather than deferring them to a worker thread. The problem with the latter is that retries and things can happen in the meantime when we want to stop that sooner. To this end: (1) Stop the error distributor from removing calls from the error_targets list so that peer->lock isn't needed to synchronise against other adds and removals. (2) Require the peer's error_targets list to be accessed with RCU, thereby avoiding the need to take peer->lock over distribution. (3) Don't attempt to affect a call's state if it is already marked complete. Signed-off-by: David Howells <dhowells@redhat.com>
2018-08-01rxrpc: Trace packet transmissionDavid Howells
Trace successful packet transmission (kernel_sendmsg() succeeded, that is) in AF_RXRPC. We can share the enum that defines the transmission points with the trace_rxrpc_tx_fail() tracepoint, so rename its constants to be applicable to both. Also, save the internal call->debug_id in the rxrpc_channel struct so that it can be used in retransmission trace lines. Signed-off-by: David Howells <dhowells@redhat.com>
2018-08-01rxrpc: remove redundant variables 'sp' and 'did_discard'YueHaibing
Variables 'sp' and 'did_discard' are being assigned, but are never used, hence they are redundant and can be removed. fix following warning: net/rxrpc/call_event.c:165:25: warning: variable 'sp' set but not used [-Wunused-but-set-variable] net/rxrpc/conn_client.c:1054:7: warning: variable 'did_discard' set but not used [-Wunused-but-set-variable] Signed-off-by: YueHaibing <yuehaibing@huawei.com> Signed-off-by: David Howells <dhowells@redhat.com>
2018-03-30rxrpc: Fix apparent leak of rxrpc_local objectsDavid Howells
rxrpc_local objects cannot be disposed of until all the connections that point to them have been RCU'd as a connection object holds refcount on the local endpoint it is communicating through. Currently, this can cause an assertion failure to occur when a network namespace is destroyed as there's no check that the RCU destructors for the connections have been run before we start trying to destroy local endpoints. The kernel reports: rxrpc: AF_RXRPC: Leaked local 0000000036a41bc1 {5} ------------[ cut here ]------------ kernel BUG at ../net/rxrpc/local_object.c:439! Fix this by keeping a count of the live connections and waiting for it to go to zero at the end of rxrpc_destroy_all_connections(). Fixes: dee46364ce6f ("rxrpc: Add RCU destruction for connections and calls") Signed-off-by: David Howells <dhowells@redhat.com>
2018-03-30rxrpc: Fix checker warnings and errorsDavid Howells
Fix various issues detected by checker. Errors: (*) rxrpc_discard_prealloc() should be using rcu_assign_pointer to set call->socket. Warnings: (*) rxrpc_service_connection_reaper() should be passing NULL rather than 0 to trace_rxrpc_conn() as the where argument. (*) rxrpc_disconnect_client_call() should get its net pointer via the call->conn rather than call->sock to avoid a warning about accessing an RCU pointer without protection. (*) Proc seq start/stop functions need annotation as they pass locks between the functions. False positives: (*) Checker doesn't correctly handle of seq-retry lock context balance in rxrpc_find_service_conn_rcu(). (*) Checker thinks execution may proceed past the BUG() in rxrpc_publish_service_conn(). (*) Variable length array warnings from SKCIPHER_REQUEST_ON_STACK() in rxkad.c. Signed-off-by: David Howells <dhowells@redhat.com>
2018-02-07rxrpc: Fix received abort handlingDavid Howells
AF_RXRPC is incorrectly sending back to the server any abort it receives for a client connection. This is due to the final-ACK offload to the connection event processor patch. The abort code is copied into the last-call information on the connection channel and then the event processor is set. Instead, the following should be done: (1) In the case of a final-ACK for a successful call, the ACK should be scheduled as before. (2) In the case of a locally generated ABORT, the ABORT details should be cached for sending in response to further packets related to that call and no further action scheduled at call disconnect time. (3) In the case of an ACK received from the peer, the call should be considered dead, no ABORT should be transmitted at this time. In response to further non-ABORT packets from the peer relating to this call, an RX_USER_ABORT ABORT should be transmitted. (4) In the case of a call killed due to network error, an RX_USER_ABORT ABORT should be cached for transmission in response to further packets, but no ABORT should be sent at this time. Fixes: 3136ef49a14c ("rxrpc: Delay terminal ACK transmission on a client call") Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-11-24rxrpc: Fix conn expiry timersDavid Howells
Fix the rxrpc connection expiry timers so that connections for closed AF_RXRPC sockets get deleted in a more timely fashion, freeing up the transport UDP port much more quickly. (1) Replace the delayed work items with work items plus timers so that timer_reduce() can be used to shorten them and so that the timer doesn't requeue the work item if the net namespace is dead. (2) Don't use queue_delayed_work() as that won't alter the timeout if the timer is already running. (3) Don't rearm the timers if the network namespace is dead. Signed-off-by: David Howells <dhowells@redhat.com>
2017-11-24rxrpc: Fix service endpoint expiryDavid Howells
RxRPC service endpoints expire like they're supposed to by the following means: (1) Mark dead rxrpc_net structs (with ->live) rather than twiddling the global service conn timeout, otherwise the first rxrpc_net struct to die will cause connections on all others to expire immediately from then on. (2) Mark local service endpoints for which the socket has been closed (->service_closed) so that the expiration timeout can be much shortened for service and client connections going through that endpoint. (3) rxrpc_put_service_conn() needs to schedule the reaper when the usage count reaches 1, not 0, as idle conns have a 1 count. (4) The accumulator for the earliest time we might want to schedule for should be initialised to jiffies + MAX_JIFFY_OFFSET, not ULONG_MAX as the comparison functions use signed arithmetic. (5) Simplify the expiration handling, adding the expiration value to the idle timestamp each time rather than keeping track of the time in the past before which the idle timestamp must go to be expired. This is much easier to read. (6) Ignore the timeouts if the net namespace is dead. (7) Restart the service reaper work item rather the client reaper. Signed-off-by: David Howells <dhowells@redhat.com>
2017-11-24rxrpc: Fix call timeoutsDavid Howells
Fix the rxrpc call expiration timeouts and make them settable from userspace. By analogy with other rx implementations, there should be three timeouts: (1) "Normal timeout" This is set for all calls and is triggered if we haven't received any packets from the peer in a while. It is measured from the last time we received any packet on that call. This is not reset by any connection packets (such as CHALLENGE/RESPONSE packets). If a service operation takes a long time, the server should generate PING ACKs at a duration that's substantially less than the normal timeout so is to keep both sides alive. This is set at 1/6 of normal timeout. (2) "Idle timeout" This is set only for a service call and is triggered if we stop receiving the DATA packets that comprise the request data. It is measured from the last time we received a DATA packet. (3) "Hard timeout" This can be set for a call and specified the maximum lifetime of that call. It should not be specified by default. Some operations (such as volume transfer) take a long time. Allow userspace to set/change the timeouts on a call with sendmsg, using a control message: RXRPC_SET_CALL_TIMEOUTS The data to the message is a number of 32-bit words, not all of which need be given: u32 hard_timeout; /* sec from first packet */ u32 idle_timeout; /* msec from packet Rx */ u32 normal_timeout; /* msec from data Rx */ This can be set in combination with any other sendmsg() that affects a call. Signed-off-by: David Howells <dhowells@redhat.com>
2017-11-24rxrpc: Delay terminal ACK transmission on a client callDavid Howells
Delay terminal ACK transmission on a client call by deferring it to the connection processor. This allows it to be skipped if we can send the next call instead, the first DATA packet of which will implicitly ack this call. Signed-off-by: David Howells <dhowells@redhat.com>
2017-08-29rxrpc: Allow failed client calls to be retriedDavid Howells
Allow a client call that failed on network error to be retried, provided that the Tx queue still holds DATA packet 1. This allows an operation to be submitted to another server or another address for the same server without having to repackage and re-encrypt the data so far processed. Two new functions are provided: (1) rxrpc_kernel_check_call() - This is used to find out the completion state of a call to guess whether it can be retried and whether it should be retried. (2) rxrpc_kernel_retry_call() - Disconnect the call from its current connection, reset the state and submit it as a new client call to a new address. The new address need not match the previous address. A call may be retried even if all the data hasn't been loaded into it yet; a partially constructed will be retained at the same point it was at when an error condition was detected. msg_data_left() can be used to find out how much data was packaged before the error occurred. Signed-off-by: David Howells <dhowells@redhat.com>
2017-06-14rxrpc: Cache the congestion window settingDavid Howells
Cache the congestion window setting that was determined during a call's transmission phase when it finishes so that it can be used by the next call to the same peer, thereby shortcutting the slow-start algorithm. The value is stored in the rxrpc_peer struct and is accessed without locking. Each call takes the value that happens to be there when it starts and just overwrites the value when it finishes. Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-06-05rxrpc: Add service upgrade support for client connectionsDavid Howells
Make it possible for a client to use AuriStor's service upgrade facility. The client does this by adding an RXRPC_UPGRADE_SERVICE control message to the first sendmsg() of a call. This takes no parameters. When recvmsg() starts returning data from the call, the service ID field in the returned msg_name will reflect the result of the upgrade attempt. If the upgrade was ignored, srx_service will match what was set in the sendmsg(); if the upgrade happened the srx_service will be altered to indicate the service the server upgraded to. Note that: (1) The choice of upgrade service is up to the server (2) Further client calls to the same server that would share a connection are blocked if an upgrade probe is in progress. (3) This should only be used to probe the service. Clients should then use the returned service ID in all subsequent communications with that server (and not set the upgrade). Note that the kernel will not retain this information should the connection expire from its cache. (4) If a server that supports upgrading is replaced by one that doesn't, whilst a connection is live, and if the replacement is running, say, OpenAFS 1.6.4 or older or an older IBM AFS, then the replacement server will not respond to packets sent to the upgraded connection. At this point, calls will time out and the server must be reprobed. Signed-off-by: David Howells <dhowells@redhat.com>
2017-06-05rxrpc: Separate the connection's protocol service ID from the lookup IDDavid Howells
Keep the rxrpc_connection struct's idea of the service ID that is exposed in the protocol separate from the service ID that's used as a lookup key. This allows the protocol service ID on a client connection to get upgraded without making the connection unfindable for other client calls that also would like to use the upgraded connection. The connection's actual service ID is then returned through recvmsg() by way of msg_name. Whilst we're at it, we get rid of the last_service_id field from each channel. The service ID is per-connection, not per-call and an entire connection is upgraded in one go. Signed-off-by: David Howells <dhowells@redhat.com>
2017-05-25rxrpc: Support network namespacingDavid Howells
Support network namespacing in AF_RXRPC with the following changes: (1) All the local endpoint, peer and call lists, locks, counters, etc. are moved into the per-namespace record. (2) All the connection tracking is moved into the per-namespace record with the exception of the client connection ID tree, which is kept global so that connection IDs are kept unique per-machine. (3) Each namespace gets its own epoch. This allows each network namespace to pretend to be a separate client machine. (4) The /proc/net/rxrpc_xxx files are now called /proc/net/rxrpc/xxx and the contents reflect the namespace. fs/afs/ should be okay with this patch as it explicitly requires the current net namespace to be init_net to permit a mount to proceed at the moment. It will, however, need updating so that cells, IP addresses and DNS records are per-namespace also. Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-04-06rxrpc: Trace client call connectionDavid Howells
Add a tracepoint (rxrpc_connect_call) to log the combination of rxrpc_call pointer, afs_call pointer/user data and wire call parameters to make it easier to match the tracebuffer contents to captured network packets. Signed-off-by: David Howells <dhowells@redhat.com>
2017-03-02sched/headers: Prepare to move signal wakeup & sigpending methods from ↵Ingo Molnar
<linux/sched.h> into <linux/sched/signal.h> Fix up affected files that include this signal functionality via sched.h. Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-01-05rxrpc: Fix handling of enums-to-string translation in tracingDavid Howells
Fix the way enum values are translated into strings in AF_RXRPC tracepoints. The problem with just doing a lookup in a normal flat array of strings or chars is that external tracing infrastructure can't find it. Rather, TRACE_DEFINE_ENUM must be used. Also sort the enums and string tables to make it easier to keep them in order so that a future patch to __print_symbolic() can be optimised to try a direct lookup into the table first before iterating over it. A couple of _proto() macro calls are removed because they refered to tables that got moved to the tracing infrastructure. The relevant data can be found by way of tracing. Signed-off-by: David Howells <dhowells@redhat.com>
2016-12-14rxrpc: abstract away knowledge of IDR internalsMatthew Wilcox
Add idr_get_cursor() / idr_set_cursor() APIs, and remove the reference to IDR_SIZE. Link: http://lkml.kernel.org/r/1480369871-5271-65-git-send-email-mawilcox@linuxonhyperv.com Signed-off-by: Matthew Wilcox <mawilcox@microsoft.com> Reviewed-by: David Howells <dhowells@redhat.com> Tested-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Konstantin Khlebnikov <koct9i@gmail.com> Cc: Ross Zwisler <ross.zwisler@linux.intel.com> Cc: Matthew Wilcox <mawilcox@microsoft.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-09-29rxrpc: When activating client conn channels, do state check inside lockDavid Howells
In rxrpc_activate_channels(), the connection cache state is checked outside of the lock, which means it can change whilst we're waking calls up, thereby changing whether or not we're allowed to wake calls up. Fix this by moving the check inside the locked region. The check to see if all the channels are currently busy can stay outside of the locked region. Whilst we're at it: (1) Split the locked section out into its own function so that we can call it from other places in a later patch. (2) Determine the mask of channels dependent on the state as we're going to add another state in a later patch that will restrict the number of simultaneous calls to 1 on a connection. Signed-off-by: David Howells <dhowells@redhat.com>
2016-09-29rxrpc: Fix exclusive client connectionsDavid Howells
Exclusive connections are currently reusable (which they shouldn't be) because rxrpc_alloc_client_connection() checks the exclusive flag in the rxrpc_connection struct before it's initialised from the function parameters. This means that the DONT_REUSE flag doesn't get set. Fix this by checking the function parameters for the exclusive flag. Signed-off-by: David Howells <dhowells@redhat.com>
2016-09-17rxrpc: Add connection tracepoint and client conn state tracepointDavid Howells
Add a pair of tracepoints, one to track rxrpc_connection struct ref counting and the other to track the client connection cache state. Signed-off-by: David Howells <dhowells@redhat.com>
2016-09-17rxrpc: Fix unexposed client conn releaseDavid Howells
If the last call on a client connection is release after the connection has had a bunch of calls allocated but before any DATA packets are sent (so that it's not yet marked RXRPC_CONN_EXPOSED), an assertion will happen in rxrpc_disconnect_client_call(). af_rxrpc: Assertion failed - 1(0x1) >= 2(0x2) is false ------------[ cut here ]------------ kernel BUG at ../net/rxrpc/conn_client.c:753! This is because it's expecting the conn to have been exposed and to have 2 or more refs - but this isn't necessarily the case. Simply remove the assertion. This allows the conn to be moved into the inactive state and deleted if it isn't resurrected before the final put is called. Signed-off-by: David Howells <dhowells@redhat.com>
2016-09-17rxrpc: Fix the putting of client connectionsDavid Howells
In rxrpc_put_one_client_conn(), if a connection has RXRPC_CONN_COUNTED set on it, then it's accounted for in rxrpc_nr_client_conns and may be on various lists - and this is cleaned up correctly. However, if the connection doesn't have RXRPC_CONN_COUNTED set on it, then the put routine returns rather than just skipping the extra bit of cleanup. Fix this by making the extra bit of clean up conditional instead and always killing off the connection. This manifests itself as connections with a zero usage count hanging around in /proc/net/rxrpc_conns because the connection allocated, but discarded, due to a race with another process that set up a parallel connection, which was then shared instead. Signed-off-by: David Howells <dhowells@redhat.com>
2016-09-07rxrpc: Cache the security index in the rxrpc_call structDavid Howells
Cache the security index in the rxrpc_call struct so that we can get at it even when the call has been disconnected and the connection pointer cleared. Signed-off-by: David Howells <dhowells@redhat.com>
2016-09-04rxrpc: Don't change the epochDavid Howells
It seems the local epoch should only be changed on boot, so remove the code that changes it for client connections. Signed-off-by: David Howells <dhowells@redhat.com>
2016-09-04rxrpc: The client call state must be changed before attachment to connDavid Howells
We must set the client call state to RXRPC_CALL_CLIENT_SEND_REQUEST before attaching the call to the connection struct, not after, as it's liable to receive errors and conn aborts as soon as the assignment is made - and these will cause its state to be changed outside of the initiating thread's control. Signed-off-by: David Howells <dhowells@redhat.com>
2016-08-30rxrpc: Trace rxrpc_call usageDavid Howells
Add a trace event for debuging rxrpc_call struct usage. Signed-off-by: David Howells <dhowells@redhat.com>
2016-08-30rxrpc: Calls should only have one terminal stateDavid Howells
Condense the terminal states of a call state machine to a single state, plus a separate completion type value. The value is then set, along with error and abort code values, only when the call is transitioned to the completion state. Helpers are provided to simplify this. Signed-off-by: David Howells <dhowells@redhat.com>
2016-08-24rxrpc: Improve management and caching of client connection objectsDavid Howells
Improve the management and caching of client rxrpc connection objects. From this point, client connections will be managed separately from service connections because AF_RXRPC controls the creation and re-use of client connections but doesn't have that luxury with service connections. Further, there will be limits on the numbers of client connections that may be live on a machine. No direct restriction will be placed on the number of client calls, excepting that each client connection can support a maximum of four concurrent calls. Note that, for a number of reasons, we don't want to simply discard a client connection as soon as the last call is apparently finished: (1) Security is negotiated per-connection and the context is then shared between all calls on that connection. The context can be negotiated again if the connection lapses, but that involves holding up calls whilst at least two packets are exchanged and various crypto bits are performed - so we'd ideally like to cache it for a little while at least. (2) If a packet goes astray, we will need to retransmit a final ACK or ABORT packet. To make this work, we need to keep around the connection details for a little while. (3) The locally held structures represent some amount of setup time, to be weighed against their occupation of memory when idle. To this end, the client connection cache is managed by a state machine on each connection. There are five states: (1) INACTIVE - The connection is not held in any list and may not have been exposed to the world. If it has been previously exposed, it was discarded from the idle list after expiring. (2) WAITING - The connection is waiting for the number of client conns to drop below the maximum capacity. Calls may be in progress upon it from when it was active and got culled. The connection is on the rxrpc_waiting_client_conns list which is kept in to-be-granted order. Culled conns with waiters go to the back of the queue just like new conns. (3) ACTIVE - The connection has at least one call in progress upon it, it may freely grant available channels to new calls and calls may be waiting on it for channels to become available. The connection is on the rxrpc_active_client_conns list which is kept in activation order for culling purposes. (4) CULLED - The connection got summarily culled to try and free up capacity. Calls currently in progress on the connection are allowed to continue, but new calls will have to wait. There can be no waiters in this state - the conn would have to go to the WAITING state instead. (5) IDLE - The connection has no calls in progress upon it and must have been exposed to the world (ie. the EXPOSED flag must be set). When it expires, the EXPOSED flag is cleared and the connection transitions to the INACTIVE state. The connection is on the rxrpc_idle_client_conns list which is kept in order of how soon they'll expire. A connection in the ACTIVE or CULLED state must have at least one active call upon it; if in the WAITING state it may have active calls upon it; other states may not have active calls. As long as a connection remains active and doesn't get culled, it may continue to process calls - even if there are connections on the wait queue. This simplifies things a bit and reduces the amount of checking we need do. There are a couple flags of relevance to the cache: (1) EXPOSED - The connection ID got exposed to the world. If this flag is set, an extra ref is added to the connection preventing it from being reaped when it has no calls outstanding. This flag is cleared and the ref dropped when a conn is discarded from the idle list. (2) DONT_REUSE - The connection should be discarded as soon as possible and should not be reused. This commit also provides a number of new settings: (*) /proc/net/rxrpc/max_client_conns The maximum number of live client connections. Above this number, new connections get added to the wait list and must wait for an active conn to be culled. Culled connections can be reused, but they will go to the back of the wait list and have to wait. (*) /proc/net/rxrpc/reap_client_conns If the number of desired connections exceeds the maximum above, the active connection list will be culled until there are only this many left in it. (*) /proc/net/rxrpc/idle_conn_expiry The normal expiry time for a client connection, provided there are fewer than reap_client_conns of them around. (*) /proc/net/rxrpc/idle_conn_fast_expiry The expedited expiry time, used when there are more than reap_client_conns of them around. Note that I combined the Tx wait queue with the channel grant wait queue to save space as only one of these should be in use at once. Note also that, for the moment, the service connection cache still uses the old connection management code. Signed-off-by: David Howells <dhowells@redhat.com>
2016-08-24rxrpc: Dup the main conn list for the proc interfaceDavid Howells
The main connection list is used for two independent purposes: primarily it is used to find connections to reap and secondarily it is used to list connections in procfs. Split the procfs list out from the reap list. This allows us to stop using the reap list for client connections when they acquire a separate management strategy from service collections. The client connections will not be on a management single list, and sometimes won't be on a management list at all. This doesn't leave them floating, however, as they will also be on an rb-tree rooted on the socket so that the socket can find them to dispatch calls. Signed-off-by: David Howells <dhowells@redhat.com>
2016-08-24rxrpc: Make /proc/net/rxrpc_calls saferDavid Howells
Make /proc/net/rxrpc_calls safer by stashing a copy of the peer pointer in the rxrpc_call struct and checking in the show routine that the peer pointer, the socket pointer and the local pointer obtained from the socket pointer aren't NULL before we use them. Signed-off-by: David Howells <dhowells@redhat.com>
2016-08-23rxrpc: Drop channel number field from rxrpc_call structDavid Howells
Drop the channel number (channel) field from the rxrpc_call struct to reduce the size of the call struct. The field is redundant: if the call is attached to a connection, the channel can be obtained from there by AND'ing with RXRPC_CHANNELMASK. Signed-off-by: David Howells <dhowells@redhat.com>
2016-08-23rxrpc: Tidy up the rxrpc_call struct a bitDavid Howells
Do a little tidying of the rxrpc_call struct: (1) in_clientflag is no longer compared against the value that's in the packet, so keeping it in this form isn't necessary. Use a flag in flags instead and provide a pair of wrapper functions. (2) We don't read the epoch value, so that can go. (3) Move what remains of the data that were used for hashing up in the struct to be with the channel number. (4) Get rid of the local pointer. We can get at this via the socket struct and we only use this in the procfs viewer. Signed-off-by: David Howells <dhowells@redhat.com>
2016-07-06rxrpc: Use RCU to access a peer's service connection treeDavid Howells
Move to using RCU access to a peer's service connection tree when routing an incoming packet. This is done using a seqlock to trigger retrying of the tree walk if a change happened. Further, we no longer get a ref on the connection looked up in the data_ready handler unless we queue the connection's work item - and then only if the refcount > 0. Note that I'm avoiding the use of a hash table for service connections because each service connection is addressed by a 62-bit number (constructed from epoch and connection ID >> 2) that would allow the client to engage in bucket stuffing, given knowledge of the hash algorithm. Peers, however, are hashed as the network address is less controllable by the client. The total number of peers will also be limited in a future commit. Signed-off-by: David Howells <dhowells@redhat.com>
2016-07-06rxrpc: Prune the contents of the rxrpc_conn_proto structDavid Howells
Prune the contents of the rxrpc_conn_proto struct. Most of the fields aren't used anymore. Signed-off-by: David Howells <dhowells@redhat.com>
2016-07-06rxrpc: Maintain an extra ref on a conn for the cache listDavid Howells
Overhaul the usage count accounting for the rxrpc_connection struct to make it easier to implement RCU access from the data_ready handler. The problem is that currently we're using a lock to prevent the garbage collector from trying to clean up a connection that we're contemplating unidling. We could just stick incoming packets on the connection we find, but we've then got a problem that we may race when dispatching a work item to process it as we need to give that a ref to prevent the rxrpc_connection struct from disappearing in the meantime. Further, incoming packets may get discarded if attached to an rxrpc_connection struct that is going away. Whilst this is not a total disaster - the client will presumably resend - it would delay processing of the call. This would affect the AFS client filesystem's service manager operation. To this end: (1) We now maintain an extra count on the connection usage count whilst it is on the connection list. This mean it is not in use when its refcount is 1. (2) When trying to reuse an old connection, we only increment the refcount if it is greater than 0. If it is 0, we replace it in the tree with a new candidate connection. (3) Two connection flags are added to indicate whether or not a connection is in the local's client connection tree (used by sendmsg) or the peer's service connection tree (used by data_ready). This makes sure that we don't try and remove a connection if it got replaced. The flags are tested under lock with the removal operation to prevent the reaper from killing the rxrpc_connection struct whilst someone else is trying to effect a replacement. This could probably be alleviated by using memory barriers between the flag set/test and the rb_tree ops. The rb_tree op would still need to be under the lock, however. (4) When trying to reap an old connection, we try to flip the usage count from 1 to 0. If it's not 1 at that point, then it must've come back to life temporarily and we ignore it. Signed-off-by: David Howells <dhowells@redhat.com>
2016-07-06rxrpc: Split client connection code out into its own fileDavid Howells
Split the client-specific connection code out into its own file. It will behave somewhat differently from the service-specific connection code, so it makes sense to separate them. Signed-off-by: David Howells <dhowells@redhat.com>
2016-07-06rxrpc: Check that the client conns cache is empty before module removalDavid Howells
Check that the client conns cache is empty before module removal and bug if not, listing any offending connections that are still present. Unfortunately, if there are connections still around, then the transport socket is still unexpectedly open and active, so we can't just unallocate the connections. Signed-off-by: David Howells <dhowells@redhat.com>
2016-06-22rxrpc: Kill the client connection bundle conceptDavid Howells
Kill off the concept of maintaining a bundle of connections to a particular target service to increase the number of call slots available for any beyond four for that service (there are four call slots per connection). This will make cleaning up the connection handling code easier and facilitate removal of the rxrpc_transport struct. Bundling can be reintroduced later if necessary. Signed-off-by: David Howells <dhowells@redhat.com>
2016-06-22rxrpc: Use IDR to allocate client conn IDs on a machine-wide basisDavid Howells
Use the IDR facility to allocate client connection IDs on a machine-wide basis so that each client connection has a unique identifier. When the connection ID space wraps, we advance the epoch by 1, thereby effectively having a 62-bit ID space. The IDR facility is then used to look up client connections during incoming packet routing instead of using an rbtree rooted on the transport. This change allows for the removal of the transport in the future and also means that client connections can be looked up directly in the data-ready handler by connection ID. The ID management code is placed in a new file, conn-client.c, to which all the client connection-specific code will eventually move. Note that the IDR tree gets very expensive on memory if the connection IDs are widely scattered throughout the number space, so we shall need to retire connections that have, say, an ID more than four times the maximum number of client conns away from the current allocation point to try and keep the IDs concentrated. We will also need to retire connections from an old epoch. Also note that, for the moment, a pointer to the transport has to be passed through into the ID allocation function so that we can take a BH lock to prevent a locking issue against in-BH lookup of client connections. This will go away later when RCU is used for server connections also. Signed-off-by: David Howells <dhowells@redhat.com>