Initial commit of d32e8d0b8d9e0ef7cf7ab2e74548982972789dfc from qemu-kvm

1 files changed, 59 insertions, 0 deletions

diff --git a/qemu-aio.h b/qemu-aio.h
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--- /dev/null
+++ b/qemu-aio.h
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+/*
+ * QEMU aio implementation
+ *
+ * Copyright IBM, Corp. 2008
+ *
+ * Authors:
+ *  Anthony Liguori   <aliguori@us.ibm.com>
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2.  See
+ * the COPYING file in the top-level directory.
+ *
+ */
+
+#ifndef QEMU_AIO_H
+#define QEMU_AIO_H
+
+#include "qemu-common.h"
+#include "qemu-char.h"
+
+/* Returns 1 if there are still outstanding AIO requests; 0 otherwise */
+typedef int (AioFlushHandler)(void *opaque);
+
+/* Runs all currently allowed AIO callbacks of completed requests in the
+ * respective AIO backend. Returns 0 if no requests was handled, non-zero
+ * if at least one queued request was handled. */
+typedef int (AioProcessQueue)(void *opaque);
+
+/* Flush any pending AIO operation. This function will block until all
+ * outstanding AIO operations have been completed or cancelled. */
+void qemu_aio_flush(void);
+
+/* Wait for a single AIO completion to occur.  This function will wait
+ * until a single AIO event has completed and it will ensure something
+ * has moved before returning. This can issue new pending aio as
+ * result of executing I/O completion or bh callbacks. */
+void qemu_aio_wait(void);
+
+/*
+ * Runs all currently allowed AIO callbacks of completed requests. Returns 0
+ * if no requests were handled, non-zero if at least one request was
+ * processed.
+ */
+int qemu_aio_process_queue(void);
+
+/* 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 either qemu_aio_wait() or qemu_aio_flush().
+ *
+ * Code that invokes AIO completion functions should rely on this function
+ * instead of qemu_set_fd_handler[2].
+ */
+int qemu_aio_set_fd_handler(int fd,
+                            IOHandler *io_read,
+                            IOHandler *io_write,
+                            AioFlushHandler *io_flush,
+                            AioProcessQueue *io_process_queue,
+                            void *opaque);
+
+#endif