dm vdo permassert: audit all of ASSERT to test for VDO_SUCCESS

Also rename ASSERT to VDO_ASSERT and ASSERT_LOG_ONLY to
VDO_ASSERT_LOG_ONLY.

But re-introduce ASSERT and ASSERT_LOG_ONLY as a placeholder
for the benefit of dm-vdo/indexer.

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

dm vdo: include <asm/current.h> to resolve current being undeclared

Reported when building on loongarch.

Reported-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
Signed-off-by: Bruce Johnston <bjohnsto@redhat.com>
Signed-off-by: Matthew Sakai <msakai@redhat.com>

dm vdo thread-registry: rename all methods to reflect vdo-only use

Otherwise, uds_ prefix is misleading (vdo_ is the new catch-all for
code that is used by vdo-only or _both_ vdo and the indexer code).

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

dm vdo: add thread and synchronization utilities

This patch adds utilities for managing and using named threads, as well as
several locking and synchronization utilities. These utilities help dm-vdo
minimize thread transitions and manage interactions between threads.

Co-developed-by: J. corwin Coburn <corwin@hurlbutnet.net>
Signed-off-by: J. corwin Coburn <corwin@hurlbutnet.net>
Co-developed-by: Michael Sclafani <dm-devel@lists.linux.dev>
Signed-off-by: Michael Sclafani <dm-devel@lists.linux.dev>
Co-developed-by: Thomas Jaskiewicz <tom@jaskiewicz.us>
Signed-off-by: Thomas Jaskiewicz <tom@jaskiewicz.us>
Co-developed-by: Bruce Johnston <bjohnsto@redhat.com>
Signed-off-by: Bruce Johnston <bjohnsto@redhat.com>
Co-developed-by: Ken Raeburn <raeburn@redhat.com>
Signed-off-by: Ken Raeburn <raeburn@redhat.com>
Signed-off-by: Matthew Sakai <msakai@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@kernel.org>