#ifndef QEMU_AIO_H
#define QEMU_AIO_H
+#include "qemu/typedefs.h"
#include "qemu-common.h"
#include "qemu/queue.h"
#include "qemu/event_notifier.h"
+#include "qemu/thread.h"
+#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);
typedef void IOHandler(void *opaque);
-typedef struct AioContext {
+struct AioContext {
GSource source;
+ /* Protects all fields from multi-threaded access */
+ RFifoLock lock;
+
/* The list of registered AIO handlers */
QLIST_HEAD(, AioHandler) aio_handlers;
*/
int walking_handlers;
+ /* Used to avoid unnecessary event_notifier_set calls in aio_notify.
+ * Writes protected by lock or BQL, reads are lockless.
+ */
+ bool dispatching;
+
+ /* lock to protect between bh's adders and deleter */
+ QemuMutex bh_lock;
+
/* Anchor of the list of Bottom Halves belonging to the context */
struct QEMUBH *first_bh;
/* Used for aio_notify. */
EventNotifier notifier;
-} AioContext;
-/* Returns 1 if there are still outstanding AIO requests; 0 otherwise */
-typedef int (AioFlushEventNotifierHandler)(EventNotifier *e);
+ /* Thread pool for performing work and receiving completion callbacks */
+ struct ThreadPool *thread_pool;
+
+ /* TimerLists for calling timers - one per clock type */
+ QEMUTimerListGroup tlg;
+};
+
+/* Used internally to synchronize aio_poll against qemu_bh_schedule. */
+void aio_set_dispatching(AioContext *ctx, bool dispatching);
/**
* aio_context_new: Allocate a new AioContext.
* 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:
*/
void aio_context_unref(AioContext *ctx);
+/* Take ownership of the AioContext. If the AioContext will be shared between
+ * 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.
+ *
+ * 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);
+
+/* Relinquish ownership of the AioContext. */
+void aio_context_release(AioContext *ctx);
+
/**
* aio_bh_new: Allocate a new bottom half structure.
*
* aio_bh_poll: Poll bottom halves for an AioContext.
*
* These are internal functions used by the QEMU main loop.
+ * And notice that multiple occurrences of aio_bh_poll cannot
+ * be called concurrently
*/
int aio_bh_poll(AioContext *ctx);
* Deleting a bottom half frees the memory that was allocated for it by
* qemu_bh_new. It also implies canceling the bottom half if it was
* scheduled.
+ * This func is async. The bottom half will do the delete action at the finial
+ * end.
*
* @bh: The bottom half to be deleted.
*/
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.
*
- * If there is no pending AIO operation or completion (bottom half),
- * return false. If there are pending AIO operations of bottom halves,
- * return true.
+ * Return whether any progress was made by executing AIO or bottom half
+ * handlers. If @blocking == true, this should always be true except
+ * if someone called aio_notify.
*
* If there are no pending bottom halves, but there are pending AIO
* operations, it may not be possible to make any progress without
*/
bool aio_poll(AioContext *ctx, bool blocking);
-#ifdef CONFIG_POSIX
-/* Returns 1 if there are still outstanding AIO requests; 0 otherwise */
-typedef int (AioFlushHandler)(void *opaque);
-
/* 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 qemu_aio_wait().
+ * be invoked when using aio_poll().
*
* Code that invokes AIO completion functions should rely on this function
* instead of qemu_set_fd_handler[2].
int fd,
IOHandler *io_read,
IOHandler *io_write,
- AioFlushHandler *io_flush,
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
- * will be invoked when using qemu_aio_wait().
+ * will be invoked when using aio_poll().
*
* Code that invokes AIO completion functions should rely on this function
* instead of event_notifier_set_handler.
*/
void aio_set_event_notifier(AioContext *ctx,
EventNotifier *notifier,
- EventNotifierHandler *io_read,
- AioFlushEventNotifierHandler *io_flush);
+ EventNotifierHandler *io_read);
/* Return a GSource that lets the main loop poll the file descriptors attached
* to this AioContext.
*/
GSource *aio_get_g_source(AioContext *ctx);
-/* Functions to operate on the main QEMU AioContext. */
+/* Return the ThreadPool bound to this AioContext */
+struct ThreadPool *aio_get_thread_pool(AioContext *ctx);
-bool qemu_aio_wait(void);
-void qemu_aio_set_event_notifier(EventNotifier *notifier,
- EventNotifierHandler *io_read,
- AioFlushEventNotifierHandler *io_flush);
+/**
+ * aio_timer_new:
+ * @ctx: the aio context
+ * @type: the clock type
+ * @scale: the scale
+ * @cb: the callback to call on timer expiry
+ * @opaque: the opaque pointer to pass to the callback
+ *
+ * Allocate a new timer attached to the context @ctx.
+ * The function is responsible for memory allocation.
+ *
+ * The preferred interface is aio_timer_init. Use that
+ * unless you really need dynamic memory allocation.
+ *
+ * Returns: a pointer to the new timer
+ */
+static inline QEMUTimer *aio_timer_new(AioContext *ctx, QEMUClockType type,
+ int scale,
+ QEMUTimerCB *cb, void *opaque)
+{
+ return timer_new_tl(ctx->tlg.tl[type], scale, cb, opaque);
+}
-#ifdef CONFIG_POSIX
-void qemu_aio_set_fd_handler(int fd,
- IOHandler *io_read,
- IOHandler *io_write,
- AioFlushHandler *io_flush,
- void *opaque);
-#endif
+/**
+ * aio_timer_init:
+ * @ctx: the aio context
+ * @ts: the timer
+ * @type: the clock type
+ * @scale: the scale
+ * @cb: the callback to call on timer expiry
+ * @opaque: the opaque pointer to pass to the callback
+ *
+ * Initialise a new timer attached to the context @ctx.
+ * The caller is responsible for memory allocation.
+ */
+static inline void aio_timer_init(AioContext *ctx,
+ QEMUTimer *ts, QEMUClockType type,
+ int scale,
+ QEMUTimerCB *cb, void *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
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