smb: server: defer the initial recv completion logic to smb_direct_negotiate_recv_work()

smb: server: defer the initial recv completion logic to smb_direct_negotiate_recv_work()

The previous change to relax WARN_ON_ONCE(SMBDIRECT_SOCKET_*) checks in
recv_done() and smb_direct_cm_handler() seems to work around the
problem that the order of initial recv completion and
RDMA_CM_EVENT_ESTABLISHED is random, but it's still
a bit ugly.

This implements a better solution deferring the recv completion
processing to smb_direct_negotiate_recv_work(), which is queued
only if both events arrived.

In order to avoid more basic changes to the main recv_done
callback, I introduced a smb_direct_negotiate_recv_done,
which is only used for the first pdu, this will allow
further cleanup and simplifications in recv_done
as a future patch.

smb_direct_negotiate_recv_work() is also very basic
with only basic error checking and the transition
from SMBDIRECT_SOCKET_NEGOTIATE_NEEDED to
SMBDIRECT_SOCKET_NEGOTIATE_RUNNING, which allows
smb_direct_prepare() to continue as before.

Cc: Tom Talpey <tom@talpey.com>
Cc: linux-cifs@vger.kernel.org
Cc: samba-technical@lists.samba.org
Signed-off-by: Stefan Metzmacher <metze@samba.org>
Acked-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>