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>

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>

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>

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>

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>

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>

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>

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>

Add a trace event for debuging rxrpc_call struct usage.

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

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>