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/*
* Copyright (c) 2008, XenSource Inc.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* * Neither the name of XenSource Inc. nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER
* OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
* LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#ifndef TAPDISK_QUEUE_H
#define TAPDISK_QUEUE_H
#include <libaio.h>
#include "io-optimize.h"
#include "scheduler.h"
struct tiocb;
struct tfilter;
typedef void (*td_queue_callback_t)(void *arg, struct tiocb *, int err);
struct tiocb {
td_queue_callback_t cb;
void *arg;
struct iocb iocb;
struct tiocb *next;
};
struct tlist {
struct tiocb *head;
struct tiocb *tail;
};
struct tqueue {
int size;
const struct tio *tio;
void *tio_data;
struct opioctx opioctx;
int queued;
struct iocb **iocbs;
/* number of iocbs pending in the aio layer */
int iocbs_pending;
/* number of tiocbs pending in the queue --
* this is likely to be larger than iocbs_pending
* due to request coalescing */
int tiocbs_pending;
/* iocbs may be deferred if the aio ring is full.
* tapdisk_queue_complete will ensure deferred
* iocbs are queued as slots become available. */
struct tlist deferred;
int tiocbs_deferred;
/* optional tapdisk filter */
struct tfilter *filter;
uint64_t deferrals;
};
struct tio {
const char *name;
size_t data_size;
int (*tio_setup) (struct tqueue *queue, int qlen);
void (*tio_destroy) (struct tqueue *queue);
int (*tio_submit) (struct tqueue *queue);
};
enum {
TIO_DRV_LIO = 1,
TIO_DRV_RWIO = 2,
};
/*
* Interface for request producer (i.e., tapdisk)
* NB: the following functions may cause additional tiocbs to be queued:
* - tapdisk_submit_tiocbs
* - tapdisk_cancel_tiocbs
* - tapdisk_complete_tiocbs
* The *_all_tiocbs variants will handle the first two cases;
* be sure to call submit after calling complete in the third case.
*/
#define tapdisk_queue_count(q) ((q)->queued)
#define tapdisk_queue_empty(q) ((q)->queued == 0)
#define tapdisk_queue_full(q) \
(((q)->tiocbs_pending + (q)->queued) >= (q)->size)
int tapdisk_init_queue(struct tqueue *, int size, int drv, struct tfilter *);
void tapdisk_free_queue(struct tqueue *);
void tapdisk_debug_queue(struct tqueue *);
void tapdisk_queue_tiocb(struct tqueue *, struct tiocb *);
int tapdisk_submit_tiocbs(struct tqueue *);
int tapdisk_submit_all_tiocbs(struct tqueue *);
int tapdisk_cancel_tiocbs(struct tqueue *);
int tapdisk_cancel_all_tiocbs(struct tqueue *);
void tapdisk_prep_tiocb(struct tiocb *, int, int, char *, size_t,
long long, td_queue_callback_t, void *);
#endif
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