linux.git/net/rxrpc/io_thread.c, branch v6.9

rxrpc: Extract useful fields from a received ACK to skb priv data

2024-03-05T23:35:26+00:00

Extract useful fields from a received ACK packet into the skb private data
early on in the process of parsing incoming packets.  This makes the ACK
fields available even before we've matched the ACK up to a call and will
allow us to deal with path MTU discovery probe responses even after the
relevant call has been completed.

Signed-off-by: David Howells 
cc: Marc Dionne 
cc: "David S. Miller" 
cc: Eric Dumazet 
cc: Jakub Kicinski 
cc: Paolo Abeni 
cc: linux-afs@lists.infradead.org
cc: netdev@vger.kernel.org

rxrpc: Allow a delay to be injected into packet reception

2023-01-31T16:38:09+00:00

If CONFIG_AF_RXRPC_DEBUG_RX_DELAY=y, then a delay is injected between
packets and errors being received and them being made available to the
processing code, thereby allowing the RTT to be artificially increased.

Signed-off-by: David Howells 
cc: Marc Dionne 
cc: linux-afs@lists.infradead.org

rxrpc: Move client call connection to the I/O thread

2023-01-06T09:43:33+00:00

Move the connection setup of client calls to the I/O thread so that a whole
load of locking and barrierage can be eliminated.  This necessitates the
app thread waiting for connection to complete before it can begin
encrypting data.

This also completes the 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: cf37b5987508 ("rxrpc: Move DATA transmission into call processor work item")
Reported-by: syzbot+c22650d2844392afdcfd@syzkaller.appspotmail.com
Signed-off-by: David Howells 
cc: Marc Dionne 
cc: linux-afs@lists.infradead.org

rxrpc: Move the client conn cache management to the I/O thread

2023-01-06T09:43:33+00:00

Move the management of the client connection cache to the I/O thread rather
than managing it from the namespace as an aggregate across all the local
endpoints within the namespace.

This will allow a load of locking to be got rid of in a future patch as
only the I/O thread will be looking at the this.

The downside is that the total number of cached connections on the system
can get higher because the limit is now per-local rather than per-netns.
We can, however, keep the number of client conns in use across the entire
netfs and use that to reduce the expiration time of idle connection.

Signed-off-by: David Howells 
cc: Marc Dionne 
cc: linux-afs@lists.infradead.org

rxrpc: Offload the completion of service conn security to the I/O thread

2023-01-06T09:43:32+00:00

Offload the completion of the challenge/response cycle on a service
connection to the I/O thread.  After the RESPONSE packet has been
successfully decrypted and verified by the work queue, offloading the
changing of the call states to the I/O thread makes iteration over the
conn's channel list simpler.

Do this by marking the RESPONSE skbuff and putting it onto the receive
queue for the I/O thread to collect.  We put it on the front of the queue
as we've already received the packet for it.

Signed-off-by: David Howells 
cc: Marc Dionne 
cc: linux-afs@lists.infradead.org

rxrpc: Tidy up abort generation infrastructure

2023-01-06T09:43:32+00:00

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 
cc: Marc Dionne 
cc: linux-afs@lists.infradead.org

rxrpc: Implement a mechanism to send an event notification to a connection

2023-01-06T09:43:31+00:00

Provide a means by which an event notification can be sent to a connection
through such that the I/O thread can pick it up and handle it rather than
doing it in a separate workqueue.

This is then used to move the deferred final ACK of a call into the I/O
thread rather than a separate work queue as part of the drive to do all
transmission from the I/O thread.

Signed-off-by: David Howells 
cc: Marc Dionne 
cc: linux-afs@lists.infradead.org

rxrpc: Separate call retransmission from other conn events

2023-01-06T09:43:31+00:00

Call the rxrpc_conn_retransmit_call() directly from rxrpc_input_packet()
rather than calling it via connection event handling.

Signed-off-by: David Howells 
cc: Marc Dionne 
cc: linux-afs@lists.infradead.org

rxrpc: Fix the return value of rxrpc_new_incoming_call()

2022-12-19T09:51:31+00:00

Dan Carpenter sayeth[1]:

  The patch 5e6ef4f1017c: "rxrpc: Make the I/O thread take over the
  call and local processor work" from Jan 23, 2020, leads to the
  following Smatch static checker warning:

	net/rxrpc/io_thread.c:283 rxrpc_input_packet()
	warn: bool is not less than zero.

Fix this (for now) by changing rxrpc_new_incoming_call() to return an int
with 0 or error code rather than bool.  Note that the actual return value
of rxrpc_input_packet() is currently ignored.  I have a separate patch to
clean that up.

Fixes: 5e6ef4f1017c ("rxrpc: Make the I/O thread take over the call and local processor work")
Reported-by: Dan Carpenter 
Signed-off-by: David Howells 
cc: Marc Dionne 
cc: linux-afs@lists.infradead.org
Link: http://lists.infradead.org/pipermail/linux-afs/2022-December/006123.html [1]
Signed-off-by: David S. Miller

rxrpc: Fix I/O thread stop

2022-12-19T09:51:31+00:00

The rxrpc I/O thread checks to see if there's any work it needs to do, and
if not, checks kthread_should_stop() before scheduling, and if it should
stop, breaks out of the loop and tries to clean up and exit.

This can, however, race with socket destruction, wherein outstanding calls
are aborted and released from the socket and then the socket unuses the
local endpoint, causing kthread_stop() to be issued.  The abort is deferred
to the I/O thread and the event can by issued between the I/O thread
checking if there's any work to be done (such as processing call aborts)
and the stop being seen.

This results in the I/O thread stopping processing of events whilst call
cleanup events are still outstanding, leading to connections or other
objects still being around and uncleaned up, which can result in assertions
being triggered, e.g.:

    rxrpc: AF_RXRPC: Leaked client conn 00000000e8009865 {2}
    ------------[ cut here ]------------
    kernel BUG at net/rxrpc/conn_client.c:64!

Fix this by retrieving the kthread_should_stop() indication, then checking
to see if there's more work to do, and going back round the loop if there
is, and breaking out of the loop only if there wasn't.

This was triggered by a syzbot test that produced some other symptom[1].

Fixes: a275da62e8c1 ("rxrpc: Create a per-local endpoint receive queue and I/O thread")
Signed-off-by: David Howells 
cc: Marc Dionne 
cc: linux-afs@lists.infradead.org
Link: https://lore.kernel.org/r/0000000000002b4a9f05ef2b616f@google.com/ [1]
Signed-off-by: David S. Miller