coroutine: move entry argument to qemu_coroutine_create

In practice the entry argument is always known at creation time, and
it is confusing that sometimes qemu_coroutine_enter is used with a
non-NULL argument to re-enter a coroutine (this happens in
block/sheepdog.c and tests/test-coroutine.c).  So pass the opaque value
at creation time, for consistency with e.g. aio_bh_new.

Mostly done with the following semantic patch:

@ entry1 @
expression entry, arg, co;
@@
- co = qemu_coroutine_create(entry);
+ co = qemu_coroutine_create(entry, arg);
  ...
- qemu_coroutine_enter(co, arg);
+ qemu_coroutine_enter(co);

@ entry2 @
expression entry, arg;
identifier co;
@@
- Coroutine *co = qemu_coroutine_create(entry);
+ Coroutine *co = qemu_coroutine_create(entry, arg);
  ...
- qemu_coroutine_enter(co, arg);
+ qemu_coroutine_enter(co);

@ entry3 @
expression entry, arg;
@@
- qemu_coroutine_enter(qemu_coroutine_create(entry), arg);
+ qemu_coroutine_enter(qemu_coroutine_create(entry, arg));

@ reentry @
expression co;
@@
- qemu_coroutine_enter(co, NULL);
+ qemu_coroutine_enter(co);

except for the aforementioned few places where the semantic patch
stumbled (as expected) and for test_co_queue, which would otherwise
produce an uninitialized variable warning.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Fam Zheng <famz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

2 files changed, 5 insertions, 7 deletions

diff --git a/include/qemu/coroutine.h b/include/qemu/coroutine.h
index 63ae7fe..ac8d4c9 100644
--- a/include/qemu/coroutine.h
+++ b/include/qemu/coroutine.h
@@ -61,16 +61,14 @@ typedef void coroutine_fn CoroutineEntry(void *opaque);
  * Create a new coroutine
  *
  * Use qemu_coroutine_enter() to actually transfer control to the coroutine.
+ * The opaque argument is passed as the argument to the entry point.
  */
-Coroutine *qemu_coroutine_create(CoroutineEntry *entry);
+Coroutine *qemu_coroutine_create(CoroutineEntry *entry, void *opaque);
 
 /**
  * Transfer control to a coroutine
- *
- * The opaque argument is passed as the argument to the entry point when
- * entering the coroutine for the first time.  It is subsequently ignored.
  */
-void qemu_coroutine_enter(Coroutine *coroutine, void *opaque);
+void qemu_coroutine_enter(Coroutine *coroutine);
 
 /**
  * Transfer control back to a coroutine's caller
diff --git a/include/qemu/main-loop.h b/include/qemu/main-loop.h
index 3fa7cfe..470f600 100644
--- a/include/qemu/main-loop.h
+++ b/include/qemu/main-loop.h
@@ -64,11 +64,11 @@ int qemu_init_main_loop(Error **errp);
  *
  *     void enter_co_bh(void *opaque) {
  *         QEMUCoroutine *co = opaque;
- *         qemu_coroutine_enter(co, NULL);
+ *         qemu_coroutine_enter(co);
  *     }
  *
  *     ...
- *     QEMUCoroutine *co = qemu_coroutine_create(coroutine_entry);
+ *     QEMUCoroutine *co = qemu_coroutine_create(coroutine_entry, NULL);
  *     QEMUBH *start_bh = qemu_bh_new(enter_co_bh, co);
  *     qemu_bh_schedule(start_bh);
  *     while (...) {