add basic stubs for aio

MAINTAINERS

@@ -132,6 +132,12 @@ M:	A2232@gmx.net
 L:	linux-m68k@lists.linux-m68k.org
 S:	Maintained
 
+AIO
+P:	Benjamin LaHaise
+M:	bcrl@redhat.com
+L:	linux-aio@kvack.org
+S:	Supported
+
 ACENIC DRIVER
 P:	Jes Sorensen
 M:	jes@trained-monkey.org

arch/i386/kernel/entry.S

@@ -754,6 +754,11 @@ ENTRY(sys_call_table)
 	.long sys_sched_getaffinity
 	.long sys_set_thread_area
 	.long sys_get_thread_area
+	.long sys_io_setup	/* 245 */
+	.long sys_io_destroy
+	.long sys_io_getevents
+	.long sys_io_submit
+	.long sys_io_cancel
 
 	.rept NR_syscalls-(.-sys_call_table)/4
 		.long sys_ni_syscall

fs/Makefile

@@ -14,7 +14,7 @@ obj-y :=	open.o read_write.o devices.o file_table.o buffer.o \
 		namei.o fcntl.o ioctl.o readdir.o select.o fifo.o locks.o \
 		dcache.o inode.o attr.o bad_inode.o file.o iobuf.o dnotify.o \
 		filesystems.o namespace.o seq_file.o xattr.o libfs.o \
-		fs-writeback.o mpage.o direct-io.o
+		fs-writeback.o mpage.o direct-io.o aio.o
 
 ifneq ($(CONFIG_NFSD),n)
 ifneq ($(CONFIG_NFSD),)

fs/aio.c

+/*
+ *	An async IO implementation for Linux
+ *	Written by Benjamin LaHaise <bcrl@redhat.com>
+ *
+ *	Implements an efficient asynchronous io interface.
+ *
+ *	Copyright 2000, 2001, 2002 Red Hat, Inc.  All Rights Reserved.
+ *
+ *	See ../COPYING for licensing terms.
+ */
+#include <linux/kernel.h>
+#include <linux/errno.h>
+#include <linux/time.h>
+#include <linux/aio_abi.h>
+
+/* io_setup:
+ *	Create an aio_context capable of receiving at least nr_events.
+ *	ctxp must not point to an aio_context that already exists, and
+ *	must be initialized to 0 prior to the call.  On successful
+ *	creation of the aio_context, *ctxp is filled in with the resulting 
+ *	handle.  May fail with -EINVAL if *ctxp is not initialized,
+ *	if the specified nr_events exceeds internal limits.  May fail 
+ *	with -EAGAIN if the specified nr_events exceeds the user's limit 
+ *	of available events.  May fail with -ENOMEM if insufficient kernel
+ *	resources are available.  May fail with -EFAULT if an invalid
+ *	pointer is passed for ctxp.  Will fail with -ENOSYS if not
+ *	implemented.
+ */
+asmlinkage long sys_io_setup(unsigned nr_events, aio_context_t *ctxp)
+{
+	return -ENOSYS;
+}
+
+/* io_destroy:
+ *	Destroy the aio_context specified.  May cancel any outstanding 
+ *	AIOs and block on completion.  Will fail with -ENOSYS if not
+ *	implemented.  May fail with -EFAULT if the context pointed to
+ *	is invalid.
+ */
+asmlinkage long sys_io_destroy(aio_context_t ctx)
+{
+	return -ENOSYS;
+}
+
+/* io_submit:
+ *	Queue the nr iocbs pointed to by iocbpp for processing.  Returns
+ *	the number of iocbs queued.  May return -EINVAL if the aio_context
+ *	specified by ctx_id is invalid, if nr is < 0, if the iocb at
+ *	*iocbpp[0] is not properly initialized, if the operation specified
+ *	is invalid for the file descriptor in the iocb.  May fail with
+ *	-EFAULT if any of the data structures point to invalid data.  May
+ *	fail with -EBADF if the file descriptor specified in the first
+ *	iocb is invalid.  May fail with -EAGAIN if insufficient resources
+ *	are available to queue any iocbs.  Will return 0 if nr is 0.  Will
+ *	fail with -ENOSYS if not implemented.
+ */
+asmlinkage long sys_io_submit(aio_context_t ctx_id, long nr,
+			      struct iocb **iocbpp)
+{
+	return -ENOSYS;
+}
+
+/* io_cancel:
+ *	Attempts to cancel an iocb previously passed to io_submit.  If
+ *	the operation is successfully cancelled, the resulting event is
+ *	copied into the memory pointed to by result without being placed
+ *	into the completion queue and 0 is returned.  May fail with
+ *	-EFAULT if any of the data structures pointed to are invalid.
+ *	May fail with -EINVAL if aio_context specified by ctx_id is
+ *	invalid.  May fail with -EAGAIN if the iocb specified was not
+ *	cancelled.  Will fail with -ENOSYS if not implemented.
+ */
+asmlinkage long sys_io_cancel(aio_context_t ctx_id, struct iocb *iocb,
+			      struct io_event *result)
+{
+	return -ENOSYS;
+}
+
+/* io_getevents:
+ *	Attempts to read at least min_nr events and up to nr events from
+ *	the completion queue for the aio_context specified by ctx_id.  May
+ *	fail with -EINVAL if ctx_id is invalid, if min_nr is out of range,
+ *	if nr is out of range, if when is out of range.  May fail with
+ *	-EFAULT if any of the memory specified to is invalid.  May return
+ *	0 or < min_nr if no events are available and the timeout specified
+ *	by when	has elapsed, where when == NULL specifies an infinite
+ *	timeout.  Note that the timeout pointed to by when is relative and
+ *	will be updated if not NULL and the operation blocks.  Will fail
+ *	with -ENOSYS if not implemented.
+ */
+asmlinkage long sys_io_getevents(aio_context_t ctx_id,
+				 long min_nr,
+				 long nr,
+				 struct io_event *events,
+				 struct timespec *when)
+{
+	return -ENOSYS;
+}
+

include/asm-i386/unistd.h

@@ -249,6 +249,11 @@
 #define __NR_sched_getaffinity	242
 #define __NR_set_thread_area	243
 #define __NR_get_thread_area	244
+#define __NR_io_setup		245
+#define __NR_io_destroy		246
+#define __NR_io_getevents	247
+#define __NR_io_submit		248
+#define __NR_io_cancel		249
 
 /* user-visible error numbers are in the range -1 - -124: see <asm-i386/errno.h> */
 

include/linux/aio_abi.h

+/* linux/aio_abi.h
+ *
+ * Copyright 2000,2001,2002 Red Hat.
+ *
+ * Written by Benjamin LaHaise <bcrl@redhat.com>
+ *
+ * Distribute under the terms of the GPLv2 (see ../../COPYING) or under 
+ * the following terms.
+ *
+ * Permission to use, copy, modify, and distribute this software and its
+ * documentation is hereby granted, provided that the above copyright
+ * notice appears in all copies.  This software is provided without any
+ * warranty, express or implied.  Red Hat makes no representations about
+ * the suitability of this software for any purpose.
+ *
+ * IN NO EVENT SHALL RED HAT BE LIABLE TO ANY PARTY FOR DIRECT, INDIRECT,
+ * SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES ARISING OUT OF THE USE OF
+ * THIS SOFTWARE AND ITS DOCUMENTATION, EVEN IF RED HAT HAS BEEN ADVISED
+ * OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ * RED HAT DISCLAIMS ANY WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE.  THE SOFTWARE PROVIDED HEREUNDER IS ON AN "AS IS" BASIS, AND
+ * RED HAT HAS NO OBLIGATION TO PROVIDE MAINTENANCE, SUPPORT, UPDATES,
+ * ENHANCEMENTS, OR MODIFICATIONS.
+ */
+#ifndef __LINUX__AIO_ABI_H
+#define __LINUX__AIO_ABI_H
+
+#include <asm/byteorder.h>
+
+typedef unsigned long	aio_context_t;
+
+enum {
+	IOCB_CMD_PREAD = 0,
+	IOCB_CMD_PWRITE = 1,
+	IOCB_CMD_FSYNC = 2,
+	IOCB_CMD_FDSYNC = 3,
+	/* These two are experimental.
+	 * IOCB_CMD_PREADX = 4,
+	 * IOCB_CMD_POLL = 5,
+	 */
+	IOCB_CMD_NOOP = 6,
+};
+
+/* read() from /dev/aio returns these structures. */
+struct io_event {
+	__u64		data;		/* the data field from the iocb */
+	__u64		obj;		/* what iocb this event came from */
+	__s64		res;		/* result code for this event */
+	__s64		res2;		/* secondary result */
+};
+
+#if defined(__LITTLE_ENDIAN)
+#define PADDED(x,y)	x, y
+#elif defined(__BIG_ENDIAN)
+#define PADDED(x,y)	y, x
+#else
+#error edit for your odd byteorder.
+#endif
+
+/*
+ * we always use a 64bit off_t when communicating
+ * with userland.  its up to libraries to do the
+ * proper padding and aio_error abstraction
+ */
+
+struct iocb {
+	/* these are internal to the kernel/libc. */
+	__u64	aio_data;	/* data to be returned in event's data */
+	__u32	PADDED(aio_key, aio_reserved1);
+				/* the kernel sets aio_key to the req # */
+
+	/* common fields */
+	__u16	aio_lio_opcode;	/* see IOCB_CMD_ above */
+	__s16	aio_reqprio;
+	__u32	aio_fildes;
+
+	__u64	aio_buf;
+	__u64	aio_nbytes;
+	__s64	aio_offset;
+
+	/* extra parameters */
+	__u64	aio_reserved2;	/* TODO: use this for a (struct sigevent *) */
+	__u64	aio_reserved3;
+}; /* 64 bytes */
+
+#undef IFBIG
+#undef IFLITTLE
+
+#endif /* __LINUX__AIO_ABI_H */
+