coroutine: add qemu_coroutine_entered() function
See the doc comments for a description of this new coroutine API.
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Fam Zheng <famz@redhat.com>
Message-id: 1474989516-18255-2-git-send-email-stefanha@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
diff --git a/include/qemu/coroutine.h b/include/qemu/coroutine.h
index 29a2078..e6a60d5 100644
--- a/include/qemu/coroutine.h
+++ b/include/qemu/coroutine.h
@@ -92,6 +92,19 @@
*/
bool qemu_in_coroutine(void);
+/**
+ * Return true if the coroutine is currently entered
+ *
+ * A coroutine is "entered" if it has not yielded from the current
+ * qemu_coroutine_enter() call used to run it. This does not mean that the
+ * coroutine is currently executing code since it may have transferred control
+ * to another coroutine using qemu_coroutine_enter().
+ *
+ * When several coroutines enter each other there may be no way to know which
+ * ones have already been entered. In such situations this function can be
+ * used to avoid recursively entering coroutines.
+ */
+bool qemu_coroutine_entered(Coroutine *co);
/**
diff --git a/util/qemu-coroutine.c b/util/qemu-coroutine.c
index 3cbf225..737bffa 100644
--- a/util/qemu-coroutine.c
+++ b/util/qemu-coroutine.c
@@ -146,3 +146,8 @@
self->caller = NULL;
qemu_coroutine_switch(self, to, COROUTINE_YIELD);
}
+
+bool qemu_coroutine_entered(Coroutine *co)
+{
+ return co->caller;
+}
