1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
|
/*
* Null block driver
*
* Authors:
* Fam Zheng <famz@redhat.com>
*
* Copyright (C) 2014 Red Hat, Inc.
*
* This work is licensed under the terms of the GNU GPL, version 2 or later.
* See the COPYING file in the top-level directory.
*/
#include "block/block_int.h"
typedef struct {
int64_t length;
} BDRVNullState;
static QemuOptsList runtime_opts = {
.name = "null",
.head = QTAILQ_HEAD_INITIALIZER(runtime_opts.head),
.desc = {
{
.name = "filename",
.type = QEMU_OPT_STRING,
.help = "",
},
{
.name = BLOCK_OPT_SIZE,
.type = QEMU_OPT_SIZE,
.help = "size of the null block",
},
{ /* end of list */ }
},
};
static int null_file_open(BlockDriverState *bs, QDict *options, int flags,
Error **errp)
{
QemuOpts *opts;
BDRVNullState *s = bs->opaque;
opts = qemu_opts_create(&runtime_opts, NULL, 0, &error_abort);
qemu_opts_absorb_qdict(opts, options, &error_abort);
s->length =
qemu_opt_get_size(opts, BLOCK_OPT_SIZE, 1 << 30);
qemu_opts_del(opts);
return 0;
}
static void null_close(BlockDriverState *bs)
{
}
static int64_t null_getlength(BlockDriverState *bs)
{
BDRVNullState *s = bs->opaque;
return s->length;
}
static coroutine_fn int null_co_readv(BlockDriverState *bs,
int64_t sector_num, int nb_sectors,
QEMUIOVector *qiov)
{
return 0;
}
static coroutine_fn int null_co_writev(BlockDriverState *bs,
int64_t sector_num, int nb_sectors,
QEMUIOVector *qiov)
{
return 0;
}
static coroutine_fn int null_co_flush(BlockDriverState *bs)
{
return 0;
}
typedef struct {
BlockDriverAIOCB common;
QEMUBH *bh;
} NullAIOCB;
static const AIOCBInfo null_aiocb_info = {
.aiocb_size = sizeof(NullAIOCB),
};
static void null_bh_cb(void *opaque)
{
NullAIOCB *acb = opaque;
acb->common.cb(acb->common.opaque, 0);
qemu_bh_delete(acb->bh);
qemu_aio_unref(acb);
}
static inline BlockDriverAIOCB *null_aio_common(BlockDriverState *bs,
BlockDriverCompletionFunc *cb,
void *opaque)
{
NullAIOCB *acb;
acb = qemu_aio_get(&null_aiocb_info, bs, cb, opaque);
acb->bh = aio_bh_new(bdrv_get_aio_context(bs), null_bh_cb, acb);
qemu_bh_schedule(acb->bh);
return &acb->common;
}
static BlockDriverAIOCB *null_aio_readv(BlockDriverState *bs,
int64_t sector_num, QEMUIOVector *qiov,
int nb_sectors,
BlockDriverCompletionFunc *cb,
void *opaque)
{
return null_aio_common(bs, cb, opaque);
}
static BlockDriverAIOCB *null_aio_writev(BlockDriverState *bs,
int64_t sector_num, QEMUIOVector *qiov,
int nb_sectors,
BlockDriverCompletionFunc *cb,
void *opaque)
{
return null_aio_common(bs, cb, opaque);
}
static BlockDriverAIOCB *null_aio_flush(BlockDriverState *bs,
BlockDriverCompletionFunc *cb,
void *opaque)
{
return null_aio_common(bs, cb, opaque);
}
static BlockDriver bdrv_null_co = {
.format_name = "null-co",
.protocol_name = "null-co",
.instance_size = sizeof(BDRVNullState),
.bdrv_file_open = null_file_open,
.bdrv_close = null_close,
.bdrv_getlength = null_getlength,
.bdrv_co_readv = null_co_readv,
.bdrv_co_writev = null_co_writev,
.bdrv_co_flush_to_disk = null_co_flush,
};
static BlockDriver bdrv_null_aio = {
.format_name = "null-aio",
.protocol_name = "null-aio",
.instance_size = sizeof(BDRVNullState),
.bdrv_file_open = null_file_open,
.bdrv_close = null_close,
.bdrv_getlength = null_getlength,
.bdrv_aio_readv = null_aio_readv,
.bdrv_aio_writev = null_aio_writev,
.bdrv_aio_flush = null_aio_flush,
};
static void bdrv_null_init(void)
{
bdrv_register(&bdrv_null_co);
bdrv_register(&bdrv_null_aio);
}
block_init(bdrv_null_init);
|
