dm vdo: remove vdo_perform_once

Remove obsolete function vdo_perform_once. Instead, initialize
necessary module state when loading the module.

Signed-off-by: Matthew Sakai <msakai@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@kernel.org>

dm vdo thread-utils: cleanup included headers

Signed-off-by: Mike Snitzer <snitzer@kernel.org>
Signed-off-by: Matthew Sakai <msakai@redhat.com>

dm vdo thread-utils: further cleanup of thread functions

Change thread function prefix from "uds_" to "vdo_" and fix
vdo_join_threads() to return void.

Signed-off-by: Mike Snitzer <snitzer@kernel.org>
Signed-off-by: Matthew Sakai <msakai@redhat.com>

dm vdo thread-utils: remove all uds_*_mutex wrappers

Just use mutex_init, mutex_lock and mutex_unlock.

Signed-off-by: Mike Snitzer <snitzer@kernel.org>
Signed-off-by: Matthew Sakai <msakai@redhat.com>

dm vdo thread-utils: push uds_*_cond interface down to indexer

Only used by indexer components. Also return void from
uds_init_cond(), remove uds_destroy_cond(), and fix up
all callers.

Signed-off-by: Mike Snitzer <snitzer@kernel.org>
Signed-off-by: Matthew Sakai <msakai@redhat.com>

dm vdo: fold thread-cond-var.c into thread-utils

Further cleanup is needed for thread-utils interfaces given many
functions should return void or be removed entirely because they
amount to obfuscation via wrappers.

Signed-off-by: Mike Snitzer <snitzer@kernel.org>
Signed-off-by: Matthew Sakai <msakai@redhat.com>

dm vdo: rename uds-threads.[ch] to thread-utils.[ch]

Signed-off-by: Mike Snitzer <snitzer@kernel.org>
Signed-off-by: Matthew Sakai <msakai@redhat.com>