blockjob: Allow nested pause

[qemu.git] / include / block / aio.h

diff --git a/include/block/aio.h b/include/block/aio.h
index c23de3cd1f9e75946858496212cb62faf5f6ce26..d2bb423de1af73ca9d869c1ed3c55167f79106ef 100644 (file)
--- a/include/block/aio.h
+++ b/include/block/aio.h
@@ -22,24 +22,27 @@
 #include "qemu/rfifolock.h"
 #include "qemu/timer.h"
 
-typedef struct BlockDriverAIOCB BlockDriverAIOCB;
-typedef void BlockDriverCompletionFunc(void *opaque, int ret);
+typedef struct BlockAIOCB BlockAIOCB;
+typedef void BlockCompletionFunc(void *opaque, int ret);
 
 typedef struct AIOCBInfo {
-    void (*cancel)(BlockDriverAIOCB *acb);
+    void (*cancel_async)(BlockAIOCB *acb);
+    AioContext *(*get_aio_context)(BlockAIOCB *acb);
     size_t aiocb_size;
 } AIOCBInfo;
 
-struct BlockDriverAIOCB {
+struct BlockAIOCB {
     const AIOCBInfo *aiocb_info;
     BlockDriverState *bs;
-    BlockDriverCompletionFunc *cb;
+    BlockCompletionFunc *cb;
     void *opaque;
+    int refcnt;
 };
 
 void *qemu_aio_get(const AIOCBInfo *aiocb_info, BlockDriverState *bs,
-                   BlockDriverCompletionFunc *cb, void *opaque);
-void qemu_aio_release(void *p);
+                   BlockCompletionFunc *cb, void *opaque);
+void qemu_aio_unref(void *p);
+void qemu_aio_ref(void *p);
 
 typedef struct AioHandler AioHandler;
 typedef void QEMUBHFunc(void *opaque);
@@ -79,9 +82,6 @@ struct AioContext {
     /* Used for aio_notify.  */
     EventNotifier notifier;
 
-    /* GPollFDs for aio_poll() */
-    GArray *pollfds;
-
     /* Thread pool for performing work and receiving completion callbacks */
     struct ThreadPool *thread_pool;
 
@@ -99,7 +99,7 @@ void aio_set_dispatching(AioContext *ctx, bool dispatching);
  * They also provide bottom halves, a service to execute a piece of code
  * as soon as possible.
  */
-AioContext *aio_context_new(void);
+AioContext *aio_context_new(Error **errp);
 
 /**
  * aio_context_ref:
@@ -118,13 +118,14 @@ void aio_context_ref(AioContext *ctx);
 void aio_context_unref(AioContext *ctx);
 
 /* Take ownership of the AioContext.  If the AioContext will be shared between
- * threads, a thread must have ownership when calling aio_poll().
+ * threads, and a thread does not want to be interrupted, it will have to
+ * take ownership around calls to aio_poll().  Otherwise, aio_poll()
+ * automatically takes care of calling aio_context_acquire and
+ * aio_context_release.
  *
- * Note that multiple threads calling aio_poll() means timers, BHs, and
- * callbacks may be invoked from a different thread than they were registered
- * from.  Therefore, code must use AioContext acquire/release or use
- * fine-grained synchronization to protect shared state if other threads will
- * be accessing it simultaneously.
+ * Access to timers and BHs from a thread that has not acquired AioContext
+ * is possible.  Access to callbacks for now must be done while the AioContext
+ * is owned by the thread (FIXME).
  */
 void aio_context_acquire(AioContext *ctx);
 
@@ -205,12 +206,25 @@ void qemu_bh_cancel(QEMUBH *bh);
 void qemu_bh_delete(QEMUBH *bh);
 
 /* Return whether there are any pending callbacks from the GSource
- * attached to the AioContext.
+ * attached to the AioContext, before g_poll is invoked.
+ *
+ * This is used internally in the implementation of the GSource.
+ */
+bool aio_prepare(AioContext *ctx);
+
+/* Return whether there are any pending callbacks from the GSource
+ * attached to the AioContext, after g_poll is invoked.
  *
  * This is used internally in the implementation of the GSource.
  */
 bool aio_pending(AioContext *ctx);
 
+/* Dispatch any pending callbacks from the GSource attached to the AioContext.
+ *
+ * This is used internally in the implementation of the GSource.
+ */
+bool aio_dispatch(AioContext *ctx);
+
 /* Progress in completing AIO work to occur.  This can issue new pending
  * aio as a result of executing I/O completion or bh callbacks.
  *
@@ -226,7 +240,6 @@ bool aio_pending(AioContext *ctx);
  */
 bool aio_poll(AioContext *ctx, bool blocking);
 
-#ifdef CONFIG_POSIX
 /* Register a file descriptor and associated callbacks.  Behaves very similarly
  * to qemu_set_fd_handler2.  Unlike qemu_set_fd_handler2, these callbacks will
  * be invoked when using aio_poll().
@@ -239,7 +252,6 @@ void aio_set_fd_handler(AioContext *ctx,
                         IOHandler *io_read,
                         IOHandler *io_write,
                         void *opaque);
-#endif
 
 /* Register an event notifier and associated callbacks.  Behaves very similarly
  * to event_notifier_set_handler.  Unlike event_notifier_set_handler, these callbacks
@@ -300,7 +312,15 @@ static inline void aio_timer_init(AioContext *ctx,
                                   int scale,
                                   QEMUTimerCB *cb, void *opaque)
 {
-    timer_init(ts, ctx->tlg.tl[type], scale, cb, opaque);
+    timer_init_tl(ts, ctx->tlg.tl[type], scale, cb, opaque);
 }
 
+/**
+ * aio_compute_timeout:
+ * @ctx: the aio context
+ *
+ * Compute the timeout that a blocking aio_poll should use.
+ */
+int64_t aio_compute_timeout(AioContext *ctx);
+
 #endif