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      1 /* include/linux/aio_abi.h
      2  *
      3  * Copyright 2000,2001,2002 Red Hat.
      4  *
      5  * Written by Benjamin LaHaise <bcrl (at) kvack.org>
      6  *
      7  * Distribute under the terms of the GPLv2 (see ../../COPYING) or under
      8  * the following terms.
      9  *
     10  * Permission to use, copy, modify, and distribute this software and its
     11  * documentation is hereby granted, provided that the above copyright
     12  * notice appears in all copies.  This software is provided without any
     13  * warranty, express or implied.  Red Hat makes no representations about
     14  * the suitability of this software for any purpose.
     15  *
     16  * IN NO EVENT SHALL RED HAT BE LIABLE TO ANY PARTY FOR DIRECT, INDIRECT,
     17  * SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES ARISING OUT OF THE USE OF
     18  * THIS SOFTWARE AND ITS DOCUMENTATION, EVEN IF RED HAT HAS BEEN ADVISED
     19  * OF THE POSSIBILITY OF SUCH DAMAGE.
     20  *
     21  * RED HAT DISCLAIMS ANY WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     22  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     23  * PURPOSE.  THE SOFTWARE PROVIDED HEREUNDER IS ON AN "AS IS" BASIS, AND
     24  * RED HAT HAS NO OBLIGATION TO PROVIDE MAINTENANCE, SUPPORT, UPDATES,
     25  * ENHANCEMENTS, OR MODIFICATIONS.
     26  */
     27 #ifndef __LINUX__AIO_ABI_H
     28 #define __LINUX__AIO_ABI_H
     29 
     30 #include <linux/types.h>
     31 #include <asm/byteorder.h>
     32 
     33 typedef unsigned long	aio_context_t;
     34 
     35 enum {
     36 	IOCB_CMD_PREAD = 0,
     37 	IOCB_CMD_PWRITE = 1,
     38 	IOCB_CMD_FSYNC = 2,
     39 	IOCB_CMD_FDSYNC = 3,
     40 	/* These two are experimental.
     41 	 * IOCB_CMD_PREADX = 4,
     42 	 * IOCB_CMD_POLL = 5,
     43 	 */
     44 	IOCB_CMD_NOOP = 6,
     45 	IOCB_CMD_PREADV = 7,
     46 	IOCB_CMD_PWRITEV = 8,
     47 };
     48 
     49 /*
     50  * Valid flags for the "aio_flags" member of the "struct iocb".
     51  *
     52  * IOCB_FLAG_RESFD - Set if the "aio_resfd" member of the "struct iocb"
     53  *                   is valid.
     54  */
     55 #define IOCB_FLAG_RESFD		(1 << 0)
     56 
     57 /* read() from /dev/aio returns these structures. */
     58 struct io_event {
     59 	__u64		data;		/* the data field from the iocb */
     60 	__u64		obj;		/* what iocb this event came from */
     61 	__s64		res;		/* result code for this event */
     62 	__s64		res2;		/* secondary result */
     63 };
     64 
     65 #if defined(__LITTLE_ENDIAN)
     66 #define PADDED(x,y)	x, y
     67 #elif defined(__BIG_ENDIAN)
     68 #define PADDED(x,y)	y, x
     69 #else
     70 #error edit for your odd byteorder.
     71 #endif
     72 
     73 /*
     74  * we always use a 64bit off_t when communicating
     75  * with userland.  its up to libraries to do the
     76  * proper padding and aio_error abstraction
     77  */
     78 
     79 struct iocb {
     80 	/* these are internal to the kernel/libc. */
     81 	__u64	aio_data;	/* data to be returned in event's data */
     82 	__u32	PADDED(aio_key, aio_reserved1);
     83 				/* the kernel sets aio_key to the req # */
     84 
     85 	/* common fields */
     86 	__u16	aio_lio_opcode;	/* see IOCB_CMD_ above */
     87 	__s16	aio_reqprio;
     88 	__u32	aio_fildes;
     89 
     90 	__u64	aio_buf;
     91 	__u64	aio_nbytes;
     92 	__s64	aio_offset;
     93 
     94 	/* extra parameters */
     95 	__u64	aio_reserved2;	/* TODO: use this for a (struct sigevent *) */
     96 
     97 	/* flags for the "struct iocb" */
     98 	__u32	aio_flags;
     99 
    100 	/*
    101 	 * if the IOCB_FLAG_RESFD flag of "aio_flags" is set, this is an
    102 	 * eventfd to signal AIO readiness to
    103 	 */
    104 	__u32	aio_resfd;
    105 }; /* 64 bytes */
    106 
    107 #undef IFBIG
    108 #undef IFLITTLE
    109 
    110 #endif /* __LINUX__AIO_ABI_H */
    111 
    112