2006-10-03 23:01:26 +02:00
										 
									 
								 
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								/* include/linux/aio_abi.h
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								 *
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								 * Copyright 2000,2001,2002 Red Hat.
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								 *
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								 * Written by Benjamin LaHaise <bcrl@kvack.org>
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								 *
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								 * Distribute under the terms of the GPLv2 (see ../../COPYING) or under 
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								 * the following terms.
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								 *
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								 * Permission to use, copy, modify, and distribute this software and its
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								 * documentation is hereby granted, provided that the above copyright
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								 * notice appears in all copies.  This software is provided without any
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								 * warranty, express or implied.  Red Hat makes no representations about
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								 * the suitability of this software for any purpose.
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								 *
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								 * IN NO EVENT SHALL RED HAT BE LIABLE TO ANY PARTY FOR DIRECT, INDIRECT,
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								 * SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES ARISING OUT OF THE USE OF
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								 * THIS SOFTWARE AND ITS DOCUMENTATION, EVEN IF RED HAT HAS BEEN ADVISED
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								 * OF THE POSSIBILITY OF SUCH DAMAGE.
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								 *
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								 * RED HAT DISCLAIMS ANY WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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								 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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								 * PURPOSE.  THE SOFTWARE PROVIDED HEREUNDER IS ON AN "AS IS" BASIS, AND
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								 * RED HAT HAS NO OBLIGATION TO PROVIDE MAINTENANCE, SUPPORT, UPDATES,
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								 * ENHANCEMENTS, OR MODIFICATIONS.
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								 */
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								#ifndef __LINUX__AIO_ABI_H
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								#define __LINUX__AIO_ABI_H
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											2009-01-30 20:20:10 +05:30
										 
									 
								 
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								#include <linux/types.h>
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								#include <asm/byteorder.h>
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											2012-02-14 12:58:56 -08:00
										 
									 
								 
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								typedef __kernel_ulong_t aio_context_t;
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								enum {
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									IOCB_CMD_PREAD = 0,
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									IOCB_CMD_PWRITE = 1,
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									IOCB_CMD_FSYNC = 2,
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									IOCB_CMD_FDSYNC = 3,
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									/* These two are experimental.
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									 * IOCB_CMD_PREADX = 4,
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									 * IOCB_CMD_POLL = 5,
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									 */
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									IOCB_CMD_NOOP = 6,
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									IOCB_CMD_PREADV = 7,
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									IOCB_CMD_PWRITEV = 8,
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											2005-04-16 15:20:36 -07:00
										 
									 
								 
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								};
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												signal/timer/event: KAIO eventfd support example
This is an example about how to add eventfd support to the current KAIO code,
in order to enable KAIO to post readiness events to a pollable fd (hence
compatible with POSIX select/poll).  The KAIO code simply signals the eventfd
fd when events are ready, and this triggers a POLLIN in the fd.  This patch
uses a reserved for future use member of the struct iocb to pass an eventfd
file descriptor, that KAIO will use to post events every time a request
completes.  At that point, an aio_getevents() will return the completed result
to a struct io_event.  I made a quick test program to verify the patch, and it
runs fine here:
http://www.xmailserver.org/eventfd-aio-test.c
The test program uses poll(2), but it'd, of course, work with select and epoll
too.
This can allow to schedule both block I/O and other poll-able devices
requests, and wait for results using select/poll/epoll.  In a typical
scenario, an application would submit KAIO request using aio_submit(), and
will also use epoll_ctl() on the whole other class of devices (that with the
addition of signals, timers and user events, now it's pretty much complete),
and then would:
	epoll_wait(...);
	for_each_event {
		if (curr_event_is_kaiofd) {
			aio_getevents();
			dispatch_aio_events();
		} else {
			dispatch_epoll_event();
		}
	}
Signed-off-by: Davide Libenzi <davidel@xmailserver.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
											
										 
										
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								/*
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								 * Valid flags for the "aio_flags" member of the "struct iocb".
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								 *
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								 * IOCB_FLAG_RESFD - Set if the "aio_resfd" member of the "struct iocb"
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								 *                   is valid.
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								 */
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								#define IOCB_FLAG_RESFD		(1 << 0)
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								/* read() from /dev/aio returns these structures. */
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								struct io_event {
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									__u64		data;		/* the data field from the iocb */
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									__u64		obj;		/* what iocb this event came from */
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									__s64		res;		/* result code for this event */
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									__s64		res2;		/* secondary result */
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								};
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											2013-03-13 14:59:45 -07:00
										 
									 
								 
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								#if defined(__BYTE_ORDER) ? __BYTE_ORDER == __LITTLE_ENDIAN : defined(__LITTLE_ENDIAN)
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								#define PADDED(x,y)	x, y
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								#elif defined(__BYTE_ORDER) ? __BYTE_ORDER == __BIG_ENDIAN : defined(__BIG_ENDIAN)
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								#define PADDED(x,y)	y, x
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								#else
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								#error edit for your odd byteorder.
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								#endif
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								/*
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								 * we always use a 64bit off_t when communicating
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								 * with userland.  its up to libraries to do the
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								 * proper padding and aio_error abstraction
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								 */
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								struct iocb {
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									/* these are internal to the kernel/libc. */
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									__u64	aio_data;	/* data to be returned in event's data */
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									__u32	PADDED(aio_key, aio_reserved1);
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												/* the kernel sets aio_key to the req # */
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									/* common fields */
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									__u16	aio_lio_opcode;	/* see IOCB_CMD_ above */
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									__s16	aio_reqprio;
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									__u32	aio_fildes;
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									__u64	aio_buf;
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									__u64	aio_nbytes;
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									__s64	aio_offset;
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									/* extra parameters */
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									__u64	aio_reserved2;	/* TODO: use this for a (struct sigevent *) */
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												signal/timer/event: KAIO eventfd support example
This is an example about how to add eventfd support to the current KAIO code,
in order to enable KAIO to post readiness events to a pollable fd (hence
compatible with POSIX select/poll).  The KAIO code simply signals the eventfd
fd when events are ready, and this triggers a POLLIN in the fd.  This patch
uses a reserved for future use member of the struct iocb to pass an eventfd
file descriptor, that KAIO will use to post events every time a request
completes.  At that point, an aio_getevents() will return the completed result
to a struct io_event.  I made a quick test program to verify the patch, and it
runs fine here:
http://www.xmailserver.org/eventfd-aio-test.c
The test program uses poll(2), but it'd, of course, work with select and epoll
too.
This can allow to schedule both block I/O and other poll-able devices
requests, and wait for results using select/poll/epoll.  In a typical
scenario, an application would submit KAIO request using aio_submit(), and
will also use epoll_ctl() on the whole other class of devices (that with the
addition of signals, timers and user events, now it's pretty much complete),
and then would:
	epoll_wait(...);
	for_each_event {
		if (curr_event_is_kaiofd) {
			aio_getevents();
			dispatch_aio_events();
		} else {
			dispatch_epoll_event();
		}
	}
Signed-off-by: Davide Libenzi <davidel@xmailserver.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
											
										 
										
											2007-05-10 22:23:21 -07:00
										 
									 
								 
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									/* flags for the "struct iocb" */
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									__u32	aio_flags;
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									/*
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									 * if the IOCB_FLAG_RESFD flag of "aio_flags" is set, this is an
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									 * eventfd to signal AIO readiness to
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									 */
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									__u32	aio_resfd;
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											2005-04-16 15:20:36 -07:00
										 
									 
								 
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								}; /* 64 bytes */
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								#undef IFBIG
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								#undef IFLITTLE
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								#endif /* __LINUX__AIO_ABI_H */
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