lockdep: Annotate lockdep assertions for context analysis

lockdep: Annotate lockdep assertions for context analysis

Clang's context analysis can be made aware of functions that assert that
locks are held.

Presence of these annotations causes the analysis to assume the context
lock is held after calls to the annotated function, and avoid false
positives with complex control-flow; for example, where not all
control-flow paths in a function require a held lock, and therefore
marking the function with __must_hold(..) is inappropriate.

Signed-off-by: Marco Elver <elver@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://patch.msgid.link/20251219154418.3592607-8-elver@google.com