Make Mutex per-Fiber instead of per-Thread

* Enables Mutex to be used as synchronization between multiple Fibers
  of the same Thread.
* With a Fiber scheduler we can yield to another Fiber on contended
  Mutex#lock instead of blocking the entire thread.
* This also makes the behavior of Mutex consistent across CRuby, JRuby and TruffleRuby.
* [Feature #16792]

1 files changed, 11 insertions, 0 deletions

diff --git a/cont.c b/cont.c
index d228107b9a..0304f4c60e 100644
--- a/cont.c
+++ b/cont.c
@@ -851,6 +851,12 @@ NOINLINE(static VALUE cont_capture(volatile int *volatile stat));
         if (!(th)->ec->tag) rb_raise(rb_eThreadError, "not running thread"); \
     } while (0)
 
+rb_thread_t*
+rb_fiber_threadptr(const rb_fiber_t *fiber)
+{
+    return fiber->cont.saved_ec.thread_ptr;
+}
+
 static VALUE
 cont_thread_value(const rb_context_t *cont)
 {
@@ -1146,6 +1152,11 @@ cont_new(VALUE klass)
     return cont;
 }
 
+VALUE rb_fiberptr_self(struct rb_fiber_struct *fiber)
+{
+    return fiber->cont.self;
+}
+
 void
 rb_fiber_init_mjit_cont(struct rb_fiber_struct *fiber)
 {