rxrpc: Fix connection-level abort handling

Fix connection-level abort handling to cache the abort and error codes
properly so that a new incoming call can be properly aborted if it races
with the pa

rxrpc: Fix connection-level abort handling

Fix connection-level abort handling to cache the abort and error codes
properly so that a new incoming call can be properly aborted if it races
with the parent connection being aborted by another CPU.

The abort_code and error parameters can then be dropped from
rxrpc_abort_calls().

Fixes: f5c17aaeb2ae ("rxrpc: Calls should only have one terminal state")
Signed-off-by: David Howells <dhowells@redhat.com>

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rxrpc: Fix the keepalive generator [ver #2]

AF_RXRPC has a keepalive message generator that generates a message for a
peer ~20s after the last transmission to that peer to keep firewall ports
open.

rxrpc: Fix the keepalive generator [ver #2]

AF_RXRPC has a keepalive message generator that generates a message for a
peer ~20s after the last transmission to that peer to keep firewall ports
open. The implementation is incorrect in the following ways:

(1) It mixes up ktime_t and time64_t types.

(2) It uses ktime_get_real(), the output of which may jump forward or
backward due to adjustments to the time of day.

(3) If the current time jumps forward too much or jumps backwards, the
generator function will crank the base of the time ring round one slot
at a time (ie. a 1s period) until it catches up, spewing out VERSION
packets as it goes.

Fix the problem by:

(1) Only using time64_t. There's no need for sub-second resolution.

(2) Use ktime_get_seconds() rather than ktime_get_real() so that time
isn't perceived to go backwards.

(3) Simplifying rxrpc_peer_keepalive_worker() by splitting it into two
parts:

(a) The "worker" function that manages the buckets and the timer.

(b) The "dispatch" function that takes the pending peers and
potentially transmits a keepalive packet before putting them back
in the ring into the slot appropriate to the revised last-Tx time.

(4) Taking everything that's pending out of the ring and splicing it into
a temporary collector list for processing.

In the case that there's been a significant jump forward, the ring
gets entirely emptied and then the time base can be warped forward
before the peers are processed.

The warping can't happen if the ring isn't empty because the slot a
peer is in is keepalive-time dependent, relative to the base time.

(5) Limit the number of iterations of the bucket array when scanning it.

(6) Set the timer to skip any empty slots as there's no point waking up if
there's nothing to do yet.

This can be triggered by an incoming call from a server after a reboot with
AF_RXRPC and AFS built into the kernel causing a peer record to be set up
before userspace is started. The system clock is then adjusted by
userspace, thereby potentially causing the keepalive generator to have a
meltdown - which leads to a message like:

watchdog: BUG: soft lockup - CPU#0 stuck for 23s! [kworker/0:1:23]
...
Workqueue: krxrpcd rxrpc_peer_keepalive_worker
EIP: lock_acquire+0x69/0x80
...
Call Trace:
? rxrpc_peer_keepalive_worker+0x5e/0x350
? _raw_spin_lock_bh+0x29/0x60
? rxrpc_peer_keepalive_worker+0x5e/0x350
? rxrpc_peer_keepalive_worker+0x5e/0x350
? __lock_acquire+0x3d3/0x870
? process_one_work+0x110/0x340
? process_one_work+0x166/0x340
? process_one_work+0x110/0x340
? worker_thread+0x39/0x3c0
? kthread+0xdb/0x110
? cancel_delayed_work+0x90/0x90
? kthread_stop+0x70/0x70
? ret_from_fork+0x19/0x24

Fixes: ace45bec6d77 ("rxrpc: Fix firewall route keepalive")
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

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rxrpc: Trace packet transmission

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_rx

rxrpc: Trace packet transmission

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>

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rxrpc: Fix the trace for terminal ACK (re)transmission

Fix the trace for terminal ACK (re)transmission to put in the right
parameters.

Signed-off-by: David Howells <dhowells@redhat.com>

rxrpc: Fix terminal retransmission connection ID to include the channel

When retransmitting the final ACK or ABORT packet for a call, the cid field
in the packet header is set to the connection's ci

rxrpc: Fix terminal retransmission connection ID to include the channel

When retransmitting the final ACK or ABORT packet for a call, the cid field
in the packet header is set to the connection's cid, but this is incorrect
as it also needs to include the channel number on that connection that the
call was made on.

Fix this by OR'ing in the channel number.

Note that this fixes the bug that:

commit 1a025028d400b23477341aa7ec2ce55f8b39b554
rxrpc: Fix handling of call quietly cancelled out on server

works around. I'm not intending to revert that as it will help protect
against problems that might occur on the server.

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>

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rxrpc: Trace UDP transmission failure

Add a tracepoint to log transmission failure from the UDP transport socket
being used by AF_RXRPC.

Signed-off-by: David Howells <dhowells@redhat.com>

rxrpc: Fix firewall route keepalive

Fix the firewall route keepalive part of AF_RXRPC which is currently
function incorrectly by replying to VERSION REPLY packets from the server
with VERSION REQUES

rxrpc: Fix firewall route keepalive

Fix the firewall route keepalive part of AF_RXRPC which is currently
function incorrectly by replying to VERSION REPLY packets from the server
with VERSION REQUEST packets.

Instead, send VERSION REPLY packets to the peers of service connections to
act as keep-alives 20s after the latest packet was transmitted to that
peer.

Also, just discard VERSION REPLY packets rather than replying to them.

Signed-off-by: David Howells <dhowells@redhat.com>

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rxrpc, afs: Use debug_ids rather than pointers in traces

In rxrpc and afs, use the debug_ids that are monotonically allocated to
various objects as they're allocated rather than pointers as kernel
p

rxrpc, afs: Use debug_ids rather than pointers in traces

In rxrpc and afs, use the debug_ids that are monotonically allocated to
various objects as they're allocated rather than pointers as kernel
pointers are now hashed making them less useful. Further, the debug ids
aren't reused anywhere nearly as quickly.

In addition, allow kernel services that use rxrpc, such as afs, to take
numbers from the rxrpc counter, assign them to their own call struct and
pass them in to rxrpc for both client and service calls so that the trace
lines for each will have the same ID tag.

Signed-off-by: David Howells <dhowells@redhat.com>

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rxrpc: Don't put crypto buffers on the stack

Don't put buffers of data to be handed to crypto on the stack as this may
cause an assertion failure in the kernel (see below). Fix this by using an
kma

rxrpc: Don't put crypto buffers on the stack

Don't put buffers of data to be handed to crypto on the stack as this may
cause an assertion failure in the kernel (see below). Fix this by using an
kmalloc'd buffer instead.

kernel BUG at ./include/linux/scatterlist.h:147!
...
RIP: 0010:rxkad_encrypt_response.isra.6+0x191/0x1b0 [rxrpc]
RSP: 0018:ffffbe2fc06cfca8 EFLAGS: 00010246
RAX: 0000000000000000 RBX: ffff989277d59900 RCX: 0000000000000028
RDX: 0000259dc06cfd88 RSI: 0000000000000025 RDI: ffffbe30406cfd88
RBP: ffffbe2fc06cfd60 R08: ffffbe2fc06cfd08 R09: ffffbe2fc06cfd08
R10: 0000000000000000 R11: 0000000000000000 R12: 1ffff7c5f80d9f95
R13: ffffbe2fc06cfd88 R14: ffff98927a3f7aa0 R15: ffffbe2fc06cfd08
FS: 0000000000000000(0000) GS:ffff98927fc00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055b1ff28f0f8 CR3: 000000001b412003 CR4: 00000000003606f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
rxkad_respond_to_challenge+0x297/0x330 [rxrpc]
rxrpc_process_connection+0xd1/0x690 [rxrpc]
? process_one_work+0x1c3/0x680
? __lock_is_held+0x59/0xa0
process_one_work+0x249/0x680
worker_thread+0x3a/0x390
? process_one_work+0x680/0x680
kthread+0x121/0x140
? kthread_create_worker_on_cpu+0x70/0x70
ret_from_fork+0x3a/0x50

Reported-by: Jonathan Billings <jsbillings@jsbillings.org>
Reported-by: Marc Dionne <marc.dionne@auristor.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Tested-by: Jonathan Billings <jsbillings@jsbillings.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

show more ...

rxrpc: Fix ACK generation from the connection event processor

Repeat terminal ACKs and now terminal ACKs are now generated from the
connection event processor rather from call handling as this allow

rxrpc: Fix ACK generation from the connection event processor

Repeat terminal ACKs and now terminal ACKs are now generated from the
connection event processor rather from call handling as this allows us to
discard client call structures as soon as possible and free up the channel
for a follow on call.

However, in ACKs so generated, the additional information trailer is
malformed because the padding that's meant to be in the middle isn't
included in what's transmitted.

Fix it so that the 3 bytes of padding are included in the transmission.

Further, the trailer is misaligned because of the padding, so assigment to
the u16 and u32 fields inside it might cause problems on some arches, so
fix this by breaking the padding and the trailer out of the packed struct.

(This also deals with potential compiler weirdies where some of the nested
structs are packed and some aren't).

The symptoms can be seen in wireshark as terminal DUPLICATE or IDLE ACK
packets in which the Max MTU, Interface MTU and rwind fields have weird
values and the Max Packets field is apparently missing.

Reported-by: Jeffrey Altman <jaltman@auristor.com>
Signed-off-by: David Howells <dhowells@redhat.com>

show more ...

rxrpc: Delay terminal ACK transmission on a client call

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

rxrpc: Delay terminal ACK transmission on a client call

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>

show more ...

rxrpc: Separate the connection's protocol service ID from the lookup ID

Keep the rxrpc_connection struct's idea of the service ID that is exposed
in the protocol separate from the service ID that's

rxrpc: Separate the connection's protocol service ID from the lookup ID

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>

show more ...

rxrpc: Trace protocol errors in received packets

Add a tracepoint (rxrpc_rx_proto) to record protocol errors in received
packets. The following changes are made:

(1) Add a function, __rxrpc_abort

rxrpc: Trace protocol errors in received packets

Add a tracepoint (rxrpc_rx_proto) to record protocol errors in received
packets. The following changes are made:

(1) Add a function, __rxrpc_abort_eproto(), to note a protocol error on a
call and mark the call aborted. This is wrapped by
rxrpc_abort_eproto() that makes the why string usable in trace.

(2) Add trace_rxrpc_rx_proto() or rxrpc_abort_eproto() to protocol error
generation points, replacing rxrpc_abort_call() with the latter.

(3) Only send an abort packet in rxkad_verify_packet*() if we actually
managed to abort the call.

Note that a trace event is also emitted if a kernel user (e.g. afs) tries
to send data through a call when it's not in the transmission phase, though
it's not technically a receive event.

Signed-off-by: David Howells <dhowells@redhat.com>

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rxrpc: Use negative error codes in rxrpc_call struct

Use negative error codes in struct rxrpc_call::error because that's what
the kernel normally deals with and to make the code consistent. We only

rxrpc: Use negative error codes in rxrpc_call struct

Use negative error codes in struct rxrpc_call::error because that's what
the kernel normally deals with and to make the code consistent. We only
turn them positive when transcribing into a cmsg for userspace recvmsg.

Signed-off-by: David Howells <dhowells@redhat.com>

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rxrpc: Ignore BUSY packets on old calls

If we receive a BUSY packet for a call we think we've just completed, the
packet is handed off to the connection processor to deal with - but the
connection p

rxrpc: Ignore BUSY packets on old calls

If we receive a BUSY packet for a call we think we've just completed, the
packet is handed off to the connection processor to deal with - but the
connection processor doesn't expect a BUSY packet and so flags a protocol
error.

Fix this by simply ignoring the BUSY packet for the moment.

The symptom of this may appear as a system call failing with EPROTO. This
may be triggered by pressing ctrl-C under some circumstances.

This comes about we abort calls due to interruption by a signal (which we
shouldn't do, but that's going to be a large fix and mostly in fs/afs/).
What happens is that we abort the call and may also abort follow up calls
too (this needs offloading somehoe). So we see a transmission of something
like the following sequence of packets:

DATA for call N
ABORT call N
DATA for call N+1
ABORT call N+1

in very quick succession on the same channel. However, the peer may have
deferred the processing of the ABORT from the call N to a background thread
and thus sees the DATA message from the call N+1 coming in before it has
cleared the channel. Thus it sends a BUSY packet[*].

[*] Note that some implementations (OpenAFS, for example) mark the BUSY
packet with one plus the callNumber of the call prior to call N.
Ordinarily, this would be call N, but there's no requirement for the
calls on a channel to be numbered strictly sequentially (the number is
required to increase).

This is wrong and means that the callNumber in the BUSY packet should
be ignored (it really ought to be N+1 since that's what it's in
response to).

Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

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rxrpc: The offset field in struct rxrpc_skb_priv is unnecessary

The offset field in struct rxrpc_skb_priv is unnecessary as the value can
always be calculated.

Signed-off-by: David Howells <dhowell

rxrpc: The offset field in struct rxrpc_skb_priv is unnecessary

The offset field in struct rxrpc_skb_priv is unnecessary as the value can
always be calculated.

Signed-off-by: David Howells <dhowells@redhat.com>

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rxrpc: Implement slow-start

Implement RxRPC slow-start, which is similar to RFC 5681 for TCP. A
tracepoint is added to log the state of the congestion management algorithm
and the decisions it make

rxrpc: Implement slow-start

Implement RxRPC slow-start, which is similar to RFC 5681 for TCP. A
tracepoint is added to log the state of the congestion management algorithm
and the decisions it makes.

Notes:

(1) Since we send fixed-size DATA packets (apart from the final packet in
each phase), counters and calculations are in terms of packets rather
than bytes.

(2) The ACK packet carries the equivalent of TCP SACK.

(3) The FLIGHT_SIZE calculation in RFC 5681 doesn't seem particularly
suited to SACK of a small number of packets. It seems that, almost
inevitably, by the time three 'duplicate' ACKs have been seen, we have
narrowed the loss down to one or two missing packets, and the
FLIGHT_SIZE calculation ends up as 2.

(4) In rxrpc_resend(), if there was no data that apparently needed
retransmission, we transmit a PING ACK to ask the peer to tell us what
its Rx window state is.

Signed-off-by: David Howells <dhowells@redhat.com>

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rxrpc: Add data Tx tracepoint and adjust Tx ACK tracepoint

Add a tracepoint to log transmission of DATA packets (including loss
injection).

Adjust the ACK transmission tracepoint to include the pac

rxrpc: Add data Tx tracepoint and adjust Tx ACK tracepoint

Add a tracepoint to log transmission of DATA packets (including loss
injection).

Adjust the ACK transmission tracepoint to include the packet serial number
and to line this up with the DATA transmission display.

Signed-off-by: David Howells <dhowells@redhat.com>

show more ...

rxrpc: Improve skb tracing

Improve sk_buff tracing within AF_RXRPC by the following means:

(1) Use an enum to note the event type rather than plain integers and use
an array of event names ra

rxrpc: Improve skb tracing

Improve sk_buff tracing within AF_RXRPC by the following means:

(1) Use an enum to note the event type rather than plain integers and use
an array of event names rather than a big multi ?: list.

(2) Distinguish Rx from Tx packets and account them separately. This
requires the call phase to be tracked so that we know what we might
find in rxtx_buffer[].

(3) Add a parameter to rxrpc_{new,see,get,free}_skb() to indicate the
event type.

(4) A pair of 'rotate' events are added to indicate packets that are about
to be rotated out of the Rx and Tx windows.

(5) A pair of 'lost' events are added, along with rxrpc_lose_skb() for
packet loss injection recording.

Signed-off-by: David Howells <dhowells@redhat.com>

show more ...

rxrpc: Add a tracepoint to log ACK transmission

Add a tracepoint to log information about ACK transmission.

Signed-off-by: David Howels <dhowells@redhat.com>

rxrpc: Add connection tracepoint and client conn state tracepoint

Add a pair of tracepoints, one to track rxrpc_connection struct ref
counting and the other to track the client connection cache stat

rxrpc: Add connection tracepoint and client conn state tracepoint

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>

show more ...

rxrpc: Rewrite the data and ack handling code

Rewrite the data and ack handling code such that:

(1) Parsing of received ACK and ABORT packets and the distribution and the
filing of DATA packe

rxrpc: Rewrite the data and ack handling code

Rewrite the data and ack handling code such that:

(1) Parsing of received ACK and ABORT packets and the distribution and the
filing of DATA packets happens entirely within the data_ready context
called from the UDP socket. This allows us to process and discard ACK
and ABORT packets much more quickly (they're no longer stashed on a
queue for a background thread to process).

(2) We avoid calling skb_clone(), pskb_pull() and pskb_trim(). We instead
keep track of the offset and length of the content of each packet in
the sk_buff metadata. This means we don't do any allocation in the
receive path.

(3) Jumbo DATA packet parsing is now done in data_ready context. Rather
than cloning the packet once for each subpacket and pulling/trimming
it, we file the packet multiple times with an annotation for each
indicating which subpacket is there. From that we can directly
calculate the offset and length.

(4) A call's receive queue can be accessed without taking locks (memory
barriers do have to be used, though).

(5) Incoming calls are set up from preallocated resources and immediately
made live. They can than have packets queued upon them and ACKs
generated. If insufficient resources exist, DATA packet #1 is given a
BUSY reply and other DATA packets are discarded).

(6) sk_buffs no longer take a ref on their parent call.

To make this work, the following changes are made:

(1) Each call's receive buffer is now a circular buffer of sk_buff
pointers (rxtx_buffer) rather than a number of sk_buff_heads spread
between the call and the socket. This permits each sk_buff to be in
the buffer multiple times. The receive buffer is reused for the
transmit buffer.

(2) A circular buffer of annotations (rxtx_annotations) is kept parallel
to the data buffer. Transmission phase annotations indicate whether a
buffered packet has been ACK'd or not and whether it needs
retransmission.

Receive phase annotations indicate whether a slot holds a whole packet
or a jumbo subpacket and, if the latter, which subpacket. They also
note whether the packet has been decrypted in place.

(3) DATA packet window tracking is much simplified. Each phase has just
two numbers representing the window (rx_hard_ack/rx_top and
tx_hard_ack/tx_top).

The hard_ack number is the sequence number before base of the window,
representing the last packet the other side says it has consumed.
hard_ack starts from 0 and the first packet is sequence number 1.

The top number is the sequence number of the highest-numbered packet
residing in the buffer. Packets between hard_ack+1 and top are
soft-ACK'd to indicate they've been received, but not yet consumed.

Four macros, before(), before_eq(), after() and after_eq() are added
to compare sequence numbers within the window. This allows for the
top of the window to wrap when the hard-ack sequence number gets close
to the limit.

Two flags, RXRPC_CALL_RX_LAST and RXRPC_CALL_TX_LAST, are added also
to indicate when rx_top and tx_top point at the packets with the
LAST_PACKET bit set, indicating the end of the phase.

(4) Calls are queued on the socket 'receive queue' rather than packets.
This means that we don't need have to invent dummy packets to queue to
indicate abnormal/terminal states and we don't have to keep metadata
packets (such as ABORTs) around

(5) The offset and length of a (sub)packet's content are now passed to
the verify_packet security op. This is currently expected to decrypt
the packet in place and validate it.

However, there's now nowhere to store the revised offset and length of
the actual data within the decrypted blob (there may be a header and
padding to skip) because an sk_buff may represent multiple packets, so
a locate_data security op is added to retrieve these details from the
sk_buff content when needed.

(6) recvmsg() now has to handle jumbo subpackets, where each subpacket is
individually secured and needs to be individually decrypted. The code
to do this is broken out into rxrpc_recvmsg_data() and shared with the
kernel API. It now iterates over the call's receive buffer rather
than walking the socket receive queue.

Additional changes:

(1) The timers are condensed to a single timer that is set for the soonest
of three timeouts (delayed ACK generation, DATA retransmission and
call lifespan).

(2) Transmission of ACK and ABORT packets is effected immediately from
process-context socket ops/kernel API calls that cause them instead of
them being punted off to a background work item. The data_ready
handler still has to defer to the background, though.

(3) A shutdown op is added to the AF_RXRPC socket so that the AFS
filesystem can shut down the socket and flush its own work items
before closing the socket to deal with any in-progress service calls.

Future additional changes that will need to be considered:

(1) Make sure that a call doesn't hog the front of the queue by receiving
data from the network as fast as userspace is consuming it to the
exclusion of other calls.

(2) Transmit delayed ACKs from within recvmsg() when we've consumed
sufficiently more packets to avoid the background work item needing to
run.

Signed-off-by: David Howells <dhowells@redhat.com>

show more ...

rxrpc: Add tracepoint for working out where aborts happen

Add a tracepoint for working out where local aborts happen. Each
tracepoint call is labelled with a 3-letter code so that they can be
disti

rxrpc: Add tracepoint for working out where aborts happen

Add a tracepoint for working out where local aborts happen. Each
tracepoint call is labelled with a 3-letter code so that they can be
distinguished - and the DATA sequence number is added too where available.

rxrpc_kernel_abort_call() also takes a 3-letter code so that AFS can
indicate the circumstances when it aborts a call.

Signed-off-by: David Howells <dhowells@redhat.com>

show more ...

rxrpc: Don't expose skbs to in-kernel users [ver #2]

Don't expose skbs to in-kernel users, such as the AFS filesystem, but
instead provide a notification hook the indicates that a call needs
attenti

rxrpc: Don't expose skbs to in-kernel users [ver #2]

Don't expose skbs to in-kernel users, such as the AFS filesystem, but
instead provide a notification hook the indicates that a call needs
attention and another that indicates that there's a new call to be
collected.

This makes the following possibilities more achievable:

(1) Call refcounting can be made simpler if skbs don't hold refs to calls.

(2) skbs referring to non-data events will be able to be freed much sooner
rather than being queued for AFS to pick up as rxrpc_kernel_recv_data
will be able to consult the call state.

(3) We can shortcut the receive phase when a call is remotely aborted
because we don't have to go through all the packets to get to the one
cancelling the operation.

(4) It makes it easier to do encryption/decryption directly between AFS's
buffers and sk_buffs.

(5) Encryption/decryption can more easily be done in the AFS's thread
contexts - usually that of the userspace process that issued a syscall
- rather than in one of rxrpc's background threads on a workqueue.

(6) AFS will be able to wait synchronously on a call inside AF_RXRPC.

To make this work, the following interface function has been added:

int rxrpc_kernel_recv_data(
struct socket *sock, struct rxrpc_call *call,
void *buffer, size_t bufsize, size_t *_offset,
bool want_more, u32 *_abort_code);

This is the recvmsg equivalent. It allows the caller to find out about the
state of a specific call and to transfer received data into a buffer
piecemeal.

afs_extract_data() and rxrpc_kernel_recv_data() now do all the extraction
logic between them. They don't wait synchronously yet because the socket
lock needs to be dealt with.

Five interface functions have been removed:

rxrpc_kernel_is_data_last()
rxrpc_kernel_get_abort_code()
rxrpc_kernel_get_error_number()
rxrpc_kernel_free_skb()
rxrpc_kernel_data_consumed()

As a temporary hack, sk_buffs going to an in-kernel call are queued on the
rxrpc_call struct (->knlrecv_queue) rather than being handed over to the
in-kernel user. To process the queue internally, a temporary function,
temp_deliver_data() has been added. This will be replaced with common code
between the rxrpc_recvmsg() path and the kernel_rxrpc_recv_data() path in a
future patch.

Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

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rxrpc: Trace rxrpc_call usage

Add a trace event for debuging rxrpc_call struct usage.

Signed-off-by: David Howells <dhowells@redhat.com>