coroutine: Move coroutine_fn to qemu/osdep.h, trim includes

block/block-hmp-cmds.h and qemu/co-shared-resource.h use coroutine_fn
without including qemu/coroutine.h.  They compile only if it's already
included from elsewhere.

I could fix that, but pulling in qemu/coroutine.h and everything it
includes just for a macro that expands into nothing feels silly.
Instead, move the macro to qemu/osdep.h.

Inclusions of qemu/coroutine.h just for coroutine_fn become
superfluous.  Drop them.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-Id: <20221221131435.3851212-3-armbru@redhat.com>

include/block/aio_task.h

@@ -25,8 +25,6 @@
 #ifndef BLOCK_AIO_TASK_H
 #define BLOCK_AIO_TASK_H
 
-#include "qemu/coroutine.h"
-
 typedef struct AioTaskPool AioTaskPool;
 typedef struct AioTask AioTask;
 typedef int coroutine_fn (*AioTaskFunc)(AioTask *task);

include/block/block-common.h

@@ -27,7 +27,6 @@
 #include "block/aio.h"
 #include "block/aio-wait.h"
 #include "qemu/iov.h"
-#include "qemu/coroutine.h"
 #include "block/accounting.h"
 #include "qemu/hbitmap.h"
 #include "qemu/transactions.h"

include/block/graph-lock.h

@@ -23,8 +23,6 @@
 #include "qemu/osdep.h"
 #include "qemu/clang-tsa.h"
 
-#include "qemu/coroutine.h"
-
 /**
  * Graph Lock API
  * This API provides a rwlock used to protect block layer

include/monitor/hmp.h

@@ -15,7 +15,6 @@
 #define HMP_H
 
 #include "qemu/readline.h"
-#include "qemu/coroutine.h"
 #include "qapi/qapi-types-common.h"
 
 bool hmp_handle_error(Monitor *mon, Error *err);

include/qemu/coroutine.h

@@ -26,23 +26,19 @@
  * waiting for events to complete.
  *
  * These functions are re-entrant and may be used outside the global mutex.
- */
-
-/**
- * Mark a function that executes in coroutine context
  *
- * Functions that execute in coroutine context cannot be called directly from
- * normal functions.  In the future it would be nice to enable compiler or
- * static checker support for catching such errors.  This annotation might make
- * it possible and in the meantime it serves as documentation.
- *
- * For example:
+ * Functions that execute in coroutine context cannot be called
+ * directly from normal functions.  Use @coroutine_fn to mark such
+ * functions.  For example:
  *
  *   static void coroutine_fn foo(void) {
  *       ....
  *   }
+ *
+ * In the future it would be nice to have the compiler or a static
+ * checker catch misuse of such functions.  This annotation might make
+ * it possible and in the meantime it serves as documentation.
  */
-#define coroutine_fn
 
 typedef struct Coroutine Coroutine;
 

include/qemu/osdep.h

@@ -157,6 +157,22 @@ extern "C" {
 
 #include "qemu/typedefs.h"
 
+/**
+ * Mark a function that executes in coroutine context
+ *
+ * Functions that execute in coroutine context cannot be called directly from
+ * normal functions.  In the future it would be nice to enable compiler or
+ * static checker support for catching such errors.  This annotation might make
+ * it possible and in the meantime it serves as documentation.
+ *
+ * For example:
+ *
+ *   static void coroutine_fn foo(void) {
+ *       ....
+ *   }
+ */
+#define coroutine_fn
+
 /*
  * For mingw, as of v6.0.0, the function implementing the assert macro is
  * not marked as noreturn, so the compiler cannot delete code following an