rxrpc: Fix potential race in error handling in afs_make_call()

If the rxrpc call set up by afs_make_call() receives an error whilst it is
transmitting the request, there's the possibility that it may get to the
point the rxrpc call is ended (after the error_kill_call label) just as the
call is queued for async processing.

This could manifest itself as call->rxcall being seen as NULL in
afs_deliver_to_call() when it tries to lock the call.

Fix this by splitting rxrpc_kernel_end_call() into a function to shut down
an rxrpc call and a function to release the caller's reference and calling
the latter only when we get to afs_put_call().

Reported-by: Jeffrey Altman <jaltman@auristor.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Tested-by: kafs-testing+fedora36_64checkkafs-build-306@auristor.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
Signed-off-by: David S. Miller <davem@davemloft.net>

rxrpc: use bvec_set_page to initialize a bvec

Use the bvec_set_page helper to initialize a bvec.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: David Howells <dhowells@redhat.com>
Link: https://lore.kernel.org/r/20230203150634.3199647-21-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

rxrpc: Tidy up abort generation infrastructure

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 <dhowells@redhat.com>
cc: Marc Dionne <marc.dionne@auristor.com>
cc: linux-afs@lists.infradead.org

rxrpc: rxperf: Fix uninitialised variable

Dan Carpenter sayeth[1]:

The patch 75bfdbf2fca3: "rxrpc: Implement an in-kernel rxperf server
for testing purposes" from Nov 3, 2022, leads to the following Smatch
static checker warning:

net/rxrpc/rxperf.c:337 rxperf_deliver_to_call()
error: uninitialized symbol 'ret'.

Fix this by initialising ret to 0. The value is only used for tracing
purposes in the rxperf server.

Fixes: 75bfdbf2fca3 ("rxrpc: Implement an in-kernel rxperf server for testing purposes")
Reported-by: Dan Carpenter <error27@gmail.com>
Signed-off-by: David Howells <dhowells@redhat.com>
cc: Marc Dionne <marc.dionne@auristor.com>
cc: linux-afs@lists.infradead.org
Link: http://lists.infradead.org/pipermail/linux-afs/2022-December/006124.html [1]
Signed-off-by: David S. Miller <davem@davemloft.net>

rxrpc: Implement an in-kernel rxperf server for testing purposes

Implement an in-kernel rxperf server to allow kernel-based rxrpc services
to be tested directly, unlike with AFS where they're accessed by the
fileserver when the latter decides it wants to.

This is implemented as a module that, if loaded, opens UDP port 7009
(afs3-rmtsys) and listens on it for incoming calls. Calls can be generated
using the rxperf command shipped with OpenAFS, for example.

Changes
=======
ver #2)
- Use min_t() instead of min().

Signed-off-by: David Howells <dhowells@redhat.com>
cc: Marc Dionne <marc.dionne@auristor.com>
cc: linux-afs@lists.infradead.org
cc: Jakub Kicinski <kuba@kernel.org>