[PATCH] uml: use host AIO support

This patch makes UML use host AIO support when it (and
/usr/include/linux/aio_abi.h) are present.  This is only the support, with no
consumers - a consumer is coming in the next patch.

Signed-off-by: Jeff Dike <jdike@addtoit.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/arch/um/include/aio.h b/arch/um/include/aio.h
new file mode 100644
index 0000000..423bae9
--- /dev/null
+++ b/arch/um/include/aio.h
@@ -0,0 +1,28 @@
+/*
+ * Copyright (C) 2004 Jeff Dike (jdike@karaya.com)
+ * Licensed under the GPL
+ */
+
+#ifndef AIO_H__
+#define AIO_H__
+
+enum aio_type { AIO_READ, AIO_WRITE, AIO_MMAP };
+
+struct aio_thread_reply {
+	void *data;
+	int err;
+};
+
+struct aio_context {
+	int reply_fd;
+	struct aio_context *next;
+};
+
+#define INIT_AIO_CONTEXT { .reply_fd	= -1, \
+			   .next	= NULL }
+
+extern int submit_aio(enum aio_type type, int fd, char *buf, int len,
+		      unsigned long long offset, int reply_fd,
+                      struct aio_context *aio);
+
+#endif