coroutine-lock: introduce qemu_co_queue_enter_all

Because qemu_co_queue_restart_all does not release the lock, it should
be used only in coroutine context.  Introduce a new function that,
like qemu_co_enter_next, does release the lock, and use it whenever
qemu_co_queue_restart_all was used outside coroutine context.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <20220427130830.150180-3-pbonzini@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

1 files changed, 13 insertions, 0 deletions

diff --git a/include/qemu/coroutine.h b/include/qemu/coroutine.h
index c23d41e..e595463 100644
--- a/include/qemu/coroutine.h
+++ b/include/qemu/coroutine.h
@@ -235,6 +235,19 @@ void qemu_co_queue_restart_all(CoQueue *queue);
 bool qemu_co_enter_next_impl(CoQueue *queue, QemuLockable *lock);
 
 /**
+ * Empties the CoQueue, waking the waiting coroutine one at a time.  Unlike
+ * qemu_co_queue_all, this function releases the lock during aio_co_wake
+ * because it is meant to be used outside coroutine context; in that case, the
+ * coroutine is entered immediately, before qemu_co_enter_all returns.
+ *
+ * If used in coroutine context, qemu_co_enter_all is equivalent to
+ * qemu_co_queue_all.
+ */
+#define qemu_co_enter_all(queue, lock) \
+    qemu_co_enter_all_impl(queue, QEMU_MAKE_LOCKABLE(lock))
+void qemu_co_enter_all_impl(CoQueue *queue, QemuLockable *lock);
+
+/**
  * Checks if the CoQueue is empty.
  */
 bool qemu_co_queue_empty(CoQueue *queue);