debuggers.hg

view tools/blktap2/drivers/tapdisk-queue.h @ 22848:6341fe0f4e5a

Added tag 4.1.0-rc2 for changeset 9dca60d88c63
author Keir Fraser <keir@xen.org>
date Tue Jan 25 14:06:55 2011 +0000 (2011-01-25)
parents 218026df8d5f
children
line source
1 /*
2 * Copyright (c) 2008, XenSource Inc.
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions are met:
7 * * Redistributions of source code must retain the above copyright
8 * notice, this list of conditions and the following disclaimer.
9 * * Redistributions in binary form must reproduce the above copyright
10 * notice, this list of conditions and the following disclaimer in the
11 * documentation and/or other materials provided with the distribution.
12 * * Neither the name of XenSource Inc. nor the names of its contributors
13 * may be used to endorse or promote products derived from this software
14 * without specific prior written permission.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
17 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
18 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
19 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER
20 * OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
21 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
22 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
23 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
24 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
25 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
26 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27 */
29 #ifndef TAPDISK_QUEUE_H
30 #define TAPDISK_QUEUE_H
32 #include <libaio.h>
34 #include "io-optimize.h"
35 #include "scheduler.h"
37 struct tiocb;
38 struct tfilter;
40 typedef void (*td_queue_callback_t)(void *arg, struct tiocb *, int err);
43 struct tiocb {
44 td_queue_callback_t cb;
45 void *arg;
47 struct iocb iocb;
48 struct tiocb *next;
49 };
51 struct tlist {
52 struct tiocb *head;
53 struct tiocb *tail;
54 };
56 struct tqueue {
57 int size;
59 const struct tio *tio;
60 void *tio_data;
62 struct opioctx opioctx;
64 int queued;
65 struct iocb **iocbs;
67 /* number of iocbs pending in the aio layer */
68 int iocbs_pending;
70 /* number of tiocbs pending in the queue --
71 * this is likely to be larger than iocbs_pending
72 * due to request coalescing */
73 int tiocbs_pending;
75 /* iocbs may be deferred if the aio ring is full.
76 * tapdisk_queue_complete will ensure deferred
77 * iocbs are queued as slots become available. */
78 struct tlist deferred;
79 int tiocbs_deferred;
81 /* optional tapdisk filter */
82 struct tfilter *filter;
84 uint64_t deferrals;
85 };
87 struct tio {
88 const char *name;
89 size_t data_size;
91 int (*tio_setup) (struct tqueue *queue, int qlen);
92 void (*tio_destroy) (struct tqueue *queue);
93 int (*tio_submit) (struct tqueue *queue);
94 };
96 enum {
97 TIO_DRV_LIO = 1,
98 TIO_DRV_RWIO = 2,
99 };
101 /*
102 * Interface for request producer (i.e., tapdisk)
103 * NB: the following functions may cause additional tiocbs to be queued:
104 * - tapdisk_submit_tiocbs
105 * - tapdisk_cancel_tiocbs
106 * - tapdisk_complete_tiocbs
107 * The *_all_tiocbs variants will handle the first two cases;
108 * be sure to call submit after calling complete in the third case.
109 */
110 #define tapdisk_queue_count(q) ((q)->queued)
111 #define tapdisk_queue_empty(q) ((q)->queued == 0)
112 #define tapdisk_queue_full(q) \
113 (((q)->tiocbs_pending + (q)->queued) >= (q)->size)
114 int tapdisk_init_queue(struct tqueue *, int size, int drv, struct tfilter *);
115 void tapdisk_free_queue(struct tqueue *);
116 void tapdisk_debug_queue(struct tqueue *);
117 void tapdisk_queue_tiocb(struct tqueue *, struct tiocb *);
118 int tapdisk_submit_tiocbs(struct tqueue *);
119 int tapdisk_submit_all_tiocbs(struct tqueue *);
120 int tapdisk_cancel_tiocbs(struct tqueue *);
121 int tapdisk_cancel_all_tiocbs(struct tqueue *);
122 void tapdisk_prep_tiocb(struct tiocb *, int, int, char *, size_t,
123 long long, td_queue_callback_t, void *);
125 #endif