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- 05 Mar, 2024 2 commits
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David Howells authored
Once all the packets transmitted as part of a call have been acked, don't permit any resending. Signed-off-by:David Howells <dhowells@redhat.com> cc: Marc Dionne <marc.dionne@auristor.com> cc: "David S. Miller" <davem@davemloft.net> cc: Eric Dumazet <edumazet@google.com> cc: Jakub Kicinski <kuba@kernel.org> cc: Paolo Abeni <pabeni@redhat.com> cc: linux-afs@lists.infradead.org cc: netdev@vger.kernel.org
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David Howells authored
Parse the received packets before going and processing timeouts as the timeouts may be reset by the reception of a packet. Signed-off-by:
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- 29 Feb, 2024 5 commits
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David Howells authored
Move rxrpc_send_ACK() to output.c to so that it is with rxrpc_send_ack_packet() prior to merging the two. Signed-off-by: -
David Howells authored
call->tx_transmitted and call->acks_prev_seq don't need to be managed with cmpxchg() and barriers as it's only used within the singular I/O thread. Signed-off-by: -
David Howells authored
Strip the atomic ops and barriering off of the call timer tracking as this is handled solely within the I/O thread, except for expect_term_by which is set by sendmsg(). Signed-off-by: -
David Howells authored
Convert the transmission buffer flags into a mask and use | and & rather than bitops functions (atomic ops are not required as only the I/O thread can manipulate them once submitted for transmission). The bottom byte can then correspond directly to the Rx protocol header flags. Signed-off-by: -
David Howells authored
Each Rx protocol packet contains a per-connection monotonically increasing serial number used to correlate outgoing messages with their replies - something that can be used for RTT calculation. Note this value in the rxrpc_txbuf struct in addition to the wire header and then log it in the rxrpc_retransmit trace for reference. Signed-off-by:
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- 05 Feb, 2024 2 commits
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David Howells authored
Fix the counting of new acks and nacks when parsing a packet - something that is used in congestion control. As the code stands, it merely notes if there are any nacks whereas what we really should do is compare the previous SACK table to the new one, assuming we get two successive ACK packets with nacks in them. However, we really don't want to do that if we can avoid it as the tables might not correspond directly as one may be shifted from the other - something that will only get harder to deal with once extended ACK tables come into full use (with a capacity of up to 8192). Instead, count the number of nacks shifted out of the old SACK, the number of nacks retained in the portion still active and the number of new acks and nacks in the new table then calculate what we need. Note this ends up a bit of an estimate as the Rx protocol allows acks to be withdrawn by the receiver and packets requested to be retransmitted. Fixes: d57a3a15 ("rxrpc: Save last ACK's SACK table rather than marking txbufs") Signed-off-by:
David S. Miller <davem@davemloft.net>
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David Howells authored
Fix the construction of delayed ACKs to not set the reference serial number as they can't be used as an RTT reference. Fixes: 17926a79 ("[AF_RXRPC]: Provide secure RxRPC sockets for use by userspace and kernel both") Signed-off-by:
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- 31 Jan, 2023 2 commits
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David Howells authored
call->ackr_window doesn't need to be atomic as ACK generation and ACK transmission are now done in the same thread, so drop the atomic64 handling and split it into two separate members. Similarly, call->ackr_nr_unacked doesn't need to be atomic now either. Signed-off-by: -
David Howells authored
When doing a call that has a single transmitted data packet and a massive amount of received data packets, we only ping for one RTT sample, which means we don't get a good reading on it. Fix this by converting occasional IDLE ACKs into PING ACKs to elicit a response. Signed-off-by:
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- 06 Jan, 2023 5 commits
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David Howells authored
All the setters of call->state are now in the I/O thread and thus the state lock is now unnecessary. Signed-off-by: -
David Howells authored
Move all the call state changes that are made in rxrpc_sendmsg() to the I/O thread. This is a step towards removing the call state lock. This requires the switch to the RXRPC_CALL_CLIENT_AWAIT_REPLY and RXRPC_CALL_SERVER_SEND_REPLY states to be done when the last packet is decanted from ->tx_sendmsg to ->tx_buffer in the I/O thread, not when it is added to ->tx_sendmsg by sendmsg(). Signed-off-by: -
David Howells authored
Tidy up the abort generation infrastructure in the following ways: (1) Create an enum and string mapping table to list the reasons an abort might be generated in tracing. (2) Replace the 3-char string with the values from (1) in the places that use that to log the abort source. This gets rid of a memcpy() in the tracepoint. (3) Subsume the rxrpc_rx_eproto tracepoint with the rxrpc_abort tracepoint and use values from (1) to indicate the trace reason. (4) Always make a call to an abort function at the point of the abort rather than stashing the values into variables and using goto to get to a place where it reported. The C optimiser will collapse the calls together as appropriate. The abort functions return a value that can be returned directly if appropriate. Note that this extends into afs also at the points where that generates an abort. To aid with this, the afs sources need to #define RXRPC_TRACE_ONLY_DEFINE_ENUMS before including the rxrpc tracing header because they don't have access to the rxrpc internal structures that some of the tracepoints make use of. Signed-off-by: -
David Howells authored
Only perform call disconnection in the I/O thread to reduce the locking requirement. This is the first part of a fix for a race that exists between call connection and call disconnection whereby the data transmission code adds the call to the peer error distribution list after the call has been disconnected (say by the rxrpc socket getting closed). The fix is to complete the process of moving call connection, data transmission and call disconnection into the I/O thread and thus forcibly serialising them. Note that the issue may predate the overhaul to an I/O thread model that were included in the merge window for v6.2, but the timing is very much changed by the change given below. Fixes: cf37b598 ("rxrpc: Move DATA transmission into call processor work item") Reported-by: syzbot+c22650d2844392afdcfd@syzkaller.appspotmail.com Signed-off-by:
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David Howells authored
Only set the abort call completion state in the I/O thread and only transmit ABORT packets from there. rxrpc_abort_call() can then be made to actually send the packet. Further, ABORT packets should only be sent if the call has been exposed to the network (ie. at least one attempted DATA transmission has occurred for it). Signed-off-by:
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- 01 Dec, 2022 13 commits
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David Howells authored
For ACKs generated inside the I/O thread, transmit the ACK at the point of generation. Where the ACK is generated outside of the I/O thread, it's offloaded to the I/O thread to transmit it. Signed-off-by: -
David Howells authored
When we've gone for >1RTT without transmitting a packet, we should reduce the ssthresh and cut the cwnd by half (as suggested in RFC2861 sec 3.1). However, we may receive ACK packets in a batch and the first of these may cut the cwnd, preventing further transmission, and each subsequent one cuts the cwnd yet further, reducing it to the floor and killing performance. Fix this by moving the cwnd reset to after doing the transmission and resetting the base time such that we don't cut the cwnd by half again for at least another RTT. Signed-off-by: -
David Howells authored
Add a tracepoint to log when a cwnd reset occurs due to lack of transmission on a call. Add stat counters to count transmission underflows (ie. when we have tx window space, but sendmsg doesn't manage to keep up), cwnd resets and transmission failures. Signed-off-by: -
David Howells authored
None of the spinlocks in rxrpc need a _bh annotation now as the RCU callback routines no longer take spinlocks and the bulk of the packet wrangling code is now run in the I/O thread, not softirq context. Signed-off-by: -
David Howells authored
Move the functions from the call->processor and local->processor work items into the domain of the I/O thread. The call event processor, now called from the I/O thread, then takes over the job of cranking the call state machine, processing incoming packets and transmitting DATA, ACK and ABORT packets. In a future patch, rxrpc_send_ACK() will transmit the ACK on the spot rather than queuing it for later transmission. The call event processor becomes purely received-skb driven. It only transmits things in response to events. We use "pokes" to queue a dummy skb to make it do things like start/resume transmitting data. Timer expiry also results in pokes. The connection event processor, becomes similar, though crypto events, such as dealing with CHALLENGE and RESPONSE packets is offloaded to a work item to avoid doing crypto in the I/O thread. The local event processor is removed and VERSION response packets are generated directly from the packet parser. Similarly, ABORTs generated in response to protocol errors will be transmitted immediately rather than being pushed onto a queue for later transmission. Changes: ======== ver #2) - Fix a couple of introduced lock context imbalances. Signed-off-by: -
David Howells authored
Move DATA transmission into the call processor work item. In a future patch, this will be called from the I/O thread rather than being itsown work item. This will allow DATA transmission to be driven directly by incoming ACKs, pokes and timers as those are processed. The Tx queue is also split: The queue of packets prepared by sendmsg is now places in call->tx_sendmsg and the packet dispatcher decants the packets into call->tx_buffer as space becomes available in the transmission window. This allows sendmsg to run ahead of the available space to try and prevent an underflow in transmission. Signed-off-by: -
David Howells authored
Split the packet input handler to make the softirq side just dump the received packet into the local endpoint receive queue and then call the remainder of the input function from the I/O thread. Signed-off-by: -
David Howells authored
Currently, rxrpc gives the call timer a ref on the call when it starts it and this is passed along to the workqueue by the timer expiration function. The problem comes when queue_work() fails (ie. the work item is already queued): the timer routine must put the ref - but this may cause the cleanup code to run. This has the unfortunate effect that the cleanup code may then be run in softirq context - which means that any spinlocks it might need to touch have to be guarded to disable softirqs (ie. they need a "_bh" suffix). Fix this by: (1) Don't give a ref to the timer. (2) Making the expiration function not do anything if the refcount is 0. Note that this is more of an optimisation. (3) Make sure that the cleanup routine waits for timer to complete. However, this has a consequence that timer cannot give a ref to the work item. Therefore the following fixes are also necessary: (4) Don't give a ref to the work item. (5) Make the work item return asap if it sees the ref count is 0. (6) Make sure that the cleanup routine waits for the work item to complete. Unfortunately, neither the timer nor the work item can simply get around the problem by just using refcount_inc_not_zero() as the waits would still have to be done, and there would still be the possibility of having to put the ref in the expiration function. Note the call work item is going to go away with the work being transferred to the I/O thread, so the wait in (6) will become obsolete. Signed-off-by: -
David Howells authored
In rxrpc tracing, use enums to generate lists of points of interest rather than __builtin_return_address() for the sk_buff tracepoint. Signed-off-by: -
David Howells authored
In rxrpc tracing, use enums to generate lists of points of interest rather than __builtin_return_address() for the rxrpc_call tracepoint Signed-off-by: -
David Howells authored
In rxrpc tracing, use enums to generate lists of points of interest rather than __builtin_return_address() for the rxrpc_local tracepoint Signed-off-by: -
David Howells authored
Remove the rxrpc_conn_parameters struct from the rxrpc_connection and rxrpc_bundle structs and emplace the members directly. These are going to get filled in from the rxrpc_call struct in future. Signed-off-by: -
David Howells authored
When retransmitting a packet, rxrpc_resend() shouldn't be attaching a ref to the call to the txbuf as that pins the call and prevents the call from clearing the packet buffer. Signed-off-by:
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- 08 Nov, 2022 7 commits
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David Howells authored
Improve the tracking of which packets need to be transmitted by saving the last ACK packet that we receive that has a populated soft-ACK table rather than marking packets. Then we can step through the soft-ACK table and look at the packets we've transmitted beyond that to determine which packets we might want to retransmit. We also look at the highest serial number that has been acked to try and guess which packets we've transmitted the peer is likely to have seen. If necessary, we send a ping to retrieve that number. One downside that might be a problem is that we can't then compare the previous acked/unacked state so easily in rxrpc_input_soft_acks() - which is a potential problem for the slow-start algorithm. Signed-off-by: -
David Howells authored
call->lock is no longer necessary, so remove it. Signed-off-by: -
David Howells authored
Change the way the Tx queueing works to make the following ends easier to achieve: (1) The filling of packets, the encryption of packets and the transmission of packets can be handled in parallel by separate threads, rather than rxrpc_sendmsg() allocating, filling, encrypting and transmitting each packet before moving onto the next one. (2) Get rid of the fixed-size ring which sets a hard limit on the number of packets that can be retained in the ring. This allows the number of packets to increase without having to allocate a very large ring or having variable-sized rings. [Note: the downside of this is that it's then less efficient to locate a packet for retransmission as we then have to step through a list and examine each buffer in the list.] (3) Allow the filler/encrypter to run ahead of the transmission window. (4) Make it easier to do zero copy UDP from the packet buffers. (5) Make it easier to do zero copy from userspace to the packet buffers - and thence to UDP (only if for unauthenticated connections). To that end, the following changes are made: (1) Use the new rxrpc_txbuf struct instead of sk_buff for keeping packets to be transmitted in. This allows them to be placed on multiple queues simultaneously. An sk_buff isn't really necessary as it's never passed on to lower-level networking code. (2) Keep the transmissable packets in a linked list on the call struct rather than in a ring. As a consequence, the annotation buffer isn't used either; rather a flag is set on the packet to indicate ackedness. (3) Use the RXRPC_CALL_TX_LAST flag to indicate that the last packet to be transmitted has been queued. Add RXRPC_CALL_TX_ALL_ACKED to indicate that all packets up to and including the last got hard acked. (4) Wire headers are now stored in the txbuf rather than being concocted on the stack and they're stored immediately before the data, thereby allowing zerocopy of a single span. (5) Don't bother with instant-resend on transmission failure; rather, leave it for a timer or an ACK packet to trigger. Signed-off-by: -
David Howells authored
Clean up the rxrpc_propose_ACK() function. If deferred PING ACK proposal is split out, it's only really needed for deferred DELAY ACKs. All other ACKs, bar terminal IDLE ACK are sent immediately. The deferred IDLE ACK submission can be handled by conversion of a DELAY ACK into an IDLE ACK if there's nothing to be SACK'd. Also, because there's a delay between an ACK being generated and being transmitted, it's possible that other ACKs of the same type will be generated during that interval. Apart from the ACK time and the serial number responded to, most of the ACK body, including window and SACK parameters, are not filled out till the point of transmission - so we can avoid generating a new ACK if there's one pending that will cover the SACK data we need to convey. Therefore, don't propose a new DELAY or IDLE ACK for a call if there's one already pending. Signed-off-by: -
David Howells authored
Allocate rxrpc_txbuf records for ACKs and put onto a queue for the transmitter thread to dispatch. Signed-off-by: -
David Howells authored
Record statistics about the different types of ACKs that have been transmitted and received and the number of ACKs that have been filled out and transmitted or that have been skipped. Signed-off-by: -
David Howells authored
Add a procfile, /proc/net/rxrpc/stats, to display some statistics about what rxrpc has been doing. Writing a blank line to the stats file will clear the increment-only counters. Allocated resource counters don't get cleared. Add some counters to count various things about DATA packets, including the number created, transmitted and retransmitted and the number received, the number of ACK-requests markings and the number of jumbo packets received. Signed-off-by:
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- 01 Sep, 2022 1 commit
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David Howells authored
Fix the calculation of the resend age to add a microsecond value as microseconds, not nanoseconds. Signed-off-by:
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- 22 May, 2022 2 commits
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David Howells authored
rxrpc has a timer to trigger resending of unacked data packets in a call. This is not cancelled when a client call switches to the receive phase on the basis that most calls don't last long enough for it to ever expire. However, if it *does* expire after we've started to receive the reply, we shouldn't then go into trying to retransmit or pinging the server to find out if an ack got lost. Fix this by skipping the resend code if we're into receiving the reply to a client call. Fixes: 17926a79 ("[AF_RXRPC]: Provide secure RxRPC sockets for use by userspace and kernel both") Signed-off-by:
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David Howells authored
The RX_USER_ABORT code should really only be used to indicate that the user of the rxrpc service (ie. userspace) implicitly caused a call to be aborted - for instance if the AF_RXRPC socket is closed whilst the call was in progress. (The user may also explicitly abort a call and specify the abort code to use). Change some of the points of generation to use other abort codes instead: (1) Abort the call with RXGEN_SS_UNMARSHAL or RXGEN_CC_UNMARSHAL if we see ENOMEM and EFAULT during received data delivery and abort with RX_CALL_DEAD in the default case. (2) Abort with RXGEN_SS_MARSHAL if we get ENOMEM whilst trying to send a reply. (3) Abort with RX_CALL_DEAD if we stop hearing from the peer if we had heard from the peer and abort with RX_CALL_TIMEOUT if we hadn't. (4) Abort with RX_CALL_DEAD if we try to disconnect a call that's not completed successfully or been aborted. Reported-by:Jeffrey Altman <jaltman@auristor.com> Signed-off-by:
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- 31 Mar, 2022 1 commit
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David Howells authored
The rxrpc_call struct has a timer used to handle various timed events relating to a call. This timer can get started from the packet input routines that are run in softirq mode with just the RCU read lock held. Unfortunately, because only the RCU read lock is held - and neither ref or other lock is taken - the call can start getting destroyed at the same time a packet comes in addressed to that call. This causes the timer - which was already stopped - to get restarted. Later, the timer dispatch code may then oops if the timer got deallocated first. Fix this by trying to take a ref on the rxrpc_call struct and, if successful, passing that ref along to the timer. If the timer was already running, the ref is discarded. The timer completion routine can then pass the ref along to the call's work item when it queues it. If the timer or work item where already queued/running, the extra ref is discarded. Fixes: a158bdd3 ("rxrpc: Fix call timeouts") Reported-by:
Marc Dionne <marc.dionne@auristor.com> Signed-off-by:
Paolo Abeni <pabeni@redhat.com>
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