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https://github.com/xen-project/xen.git
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Keir Fraser
fedebce364
Hide tapdisk support for different raw I/O interfaces behind a new struct tio. Libaio remains to dominate the interface, requiring everyone to dispatch iocb/ioevent structs. Backends: - lio: Kernel AIO via libaio. - rwio: Canonical read/write() mode. Misc: - Fixes a bug in tapdisk-vbd which locks up the sync io mode. - Wants a PERROR macro in blktaplib.h - Removes dead code in qcow2raw to make it link again. Signed-off-by: Daniel Stodden <daniel.stodden@citrix.com> Signed-off-by: Jake Wires <jake.wires@citrix.com>
126 lines
4.1 KiB
C
126 lines
4.1 KiB
C
/*
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* Copyright (c) 2008, XenSource Inc.
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions are met:
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* * Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* * Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* * Neither the name of XenSource Inc. nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER
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* OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
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* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
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* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
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* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
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* LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
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* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
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* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#ifndef TAPDISK_QUEUE_H
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#define TAPDISK_QUEUE_H
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#include <libaio.h>
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#include "io-optimize.h"
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#include "scheduler.h"
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struct tiocb;
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struct tfilter;
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typedef void (*td_queue_callback_t)(void *arg, struct tiocb *, int err);
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struct tiocb {
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td_queue_callback_t cb;
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void *arg;
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struct iocb iocb;
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struct tiocb *next;
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};
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struct tlist {
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struct tiocb *head;
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struct tiocb *tail;
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};
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struct tqueue {
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int size;
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const struct tio *tio;
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void *tio_data;
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struct opioctx opioctx;
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int queued;
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struct iocb **iocbs;
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/* number of iocbs pending in the aio layer */
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int iocbs_pending;
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/* number of tiocbs pending in the queue --
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* this is likely to be larger than iocbs_pending
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* due to request coalescing */
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int tiocbs_pending;
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/* iocbs may be deferred if the aio ring is full.
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* tapdisk_queue_complete will ensure deferred
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* iocbs are queued as slots become available. */
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struct tlist deferred;
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int tiocbs_deferred;
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/* optional tapdisk filter */
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struct tfilter *filter;
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uint64_t deferrals;
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};
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struct tio {
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const char *name;
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size_t data_size;
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int (*tio_setup) (struct tqueue *queue, int qlen);
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void (*tio_destroy) (struct tqueue *queue);
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int (*tio_submit) (struct tqueue *queue);
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};
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enum {
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TIO_DRV_LIO = 1,
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TIO_DRV_RWIO = 2,
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};
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/*
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* Interface for request producer (i.e., tapdisk)
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* NB: the following functions may cause additional tiocbs to be queued:
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* - tapdisk_submit_tiocbs
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* - tapdisk_cancel_tiocbs
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* - tapdisk_complete_tiocbs
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* The *_all_tiocbs variants will handle the first two cases;
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* be sure to call submit after calling complete in the third case.
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*/
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#define tapdisk_queue_count(q) ((q)->queued)
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#define tapdisk_queue_empty(q) ((q)->queued == 0)
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#define tapdisk_queue_full(q) \
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(((q)->tiocbs_pending + (q)->queued) >= (q)->size)
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int tapdisk_init_queue(struct tqueue *, int size, int drv, struct tfilter *);
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void tapdisk_free_queue(struct tqueue *);
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void tapdisk_debug_queue(struct tqueue *);
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void tapdisk_queue_tiocb(struct tqueue *, struct tiocb *);
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int tapdisk_submit_tiocbs(struct tqueue *);
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int tapdisk_submit_all_tiocbs(struct tqueue *);
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int tapdisk_cancel_tiocbs(struct tqueue *);
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int tapdisk_cancel_all_tiocbs(struct tqueue *);
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void tapdisk_prep_tiocb(struct tiocb *, int, int, char *, size_t,
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long long, td_queue_callback_t, void *);
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#endif
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