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4f999d05 KW |
1 | /* |
2 | * QEMU System Emulator | |
3 | * | |
4 | * Copyright (c) 2003-2008 Fabrice Bellard | |
5 | * | |
6 | * Permission is hereby granted, free of charge, to any person obtaining a copy | |
7 | * of this software and associated documentation files (the "Software"), to deal | |
8 | * in the Software without restriction, including without limitation the rights | |
9 | * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell | |
10 | * copies of the Software, and to permit persons to whom the Software is | |
11 | * furnished to do so, subject to the following conditions: | |
12 | * | |
13 | * The above copyright notice and this permission notice shall be included in | |
14 | * all copies or substantial portions of the Software. | |
15 | * | |
16 | * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR | |
17 | * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, | |
18 | * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL | |
19 | * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER | |
20 | * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, | |
21 | * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN | |
22 | * THE SOFTWARE. | |
23 | */ | |
24 | ||
25 | #include "qemu-common.h" | |
9a1e9481 KW |
26 | #include "qemu-aio.h" |
27 | ||
384acbf4 KW |
28 | /* Anchor of the list of Bottom Halves belonging to the context */ |
29 | static struct QEMUBH *first_bh; | |
4f999d05 KW |
30 | |
31 | /***********************************************************/ | |
32 | /* bottom halves (can be seen as timers which expire ASAP) */ | |
33 | ||
34 | struct QEMUBH { | |
35 | QEMUBHFunc *cb; | |
36 | void *opaque; | |
37 | int scheduled; | |
38 | int idle; | |
39 | int deleted; | |
40 | QEMUBH *next; | |
41 | }; | |
42 | ||
4f999d05 KW |
43 | QEMUBH *qemu_bh_new(QEMUBHFunc *cb, void *opaque) |
44 | { | |
45 | QEMUBH *bh; | |
7267c094 | 46 | bh = g_malloc0(sizeof(QEMUBH)); |
4f999d05 KW |
47 | bh->cb = cb; |
48 | bh->opaque = opaque; | |
384acbf4 KW |
49 | bh->next = first_bh; |
50 | first_bh = bh; | |
4f999d05 KW |
51 | return bh; |
52 | } | |
53 | ||
54 | int qemu_bh_poll(void) | |
55 | { | |
7887f620 | 56 | QEMUBH *bh, **bhp, *next; |
4f999d05 | 57 | int ret; |
648fb0ea KW |
58 | static int nesting = 0; |
59 | ||
60 | nesting++; | |
4f999d05 KW |
61 | |
62 | ret = 0; | |
384acbf4 | 63 | for (bh = first_bh; bh; bh = next) { |
7887f620 | 64 | next = bh->next; |
4f999d05 KW |
65 | if (!bh->deleted && bh->scheduled) { |
66 | bh->scheduled = 0; | |
67 | if (!bh->idle) | |
68 | ret = 1; | |
69 | bh->idle = 0; | |
70 | bh->cb(bh->opaque); | |
71 | } | |
72 | } | |
73 | ||
648fb0ea KW |
74 | nesting--; |
75 | ||
4f999d05 | 76 | /* remove deleted bhs */ |
648fb0ea KW |
77 | if (!nesting) { |
78 | bhp = &first_bh; | |
79 | while (*bhp) { | |
80 | bh = *bhp; | |
81 | if (bh->deleted) { | |
82 | *bhp = bh->next; | |
83 | g_free(bh); | |
84 | } else { | |
85 | bhp = &bh->next; | |
86 | } | |
87 | } | |
4f999d05 KW |
88 | } |
89 | ||
90 | return ret; | |
91 | } | |
92 | ||
93 | void qemu_bh_schedule_idle(QEMUBH *bh) | |
94 | { | |
95 | if (bh->scheduled) | |
96 | return; | |
97 | bh->scheduled = 1; | |
98 | bh->idle = 1; | |
99 | } | |
100 | ||
101 | void qemu_bh_schedule(QEMUBH *bh) | |
102 | { | |
103 | if (bh->scheduled) | |
104 | return; | |
105 | bh->scheduled = 1; | |
106 | bh->idle = 0; | |
107 | /* stop the currently executing CPU to execute the BH ASAP */ | |
108 | qemu_notify_event(); | |
109 | } | |
110 | ||
111 | void qemu_bh_cancel(QEMUBH *bh) | |
112 | { | |
113 | bh->scheduled = 0; | |
114 | } | |
115 | ||
116 | void qemu_bh_delete(QEMUBH *bh) | |
117 | { | |
118 | bh->scheduled = 0; | |
119 | bh->deleted = 1; | |
120 | } | |
121 | ||
122 | void qemu_bh_update_timeout(int *timeout) | |
123 | { | |
124 | QEMUBH *bh; | |
125 | ||
384acbf4 | 126 | for (bh = first_bh; bh; bh = bh->next) { |
4f999d05 KW |
127 | if (!bh->deleted && bh->scheduled) { |
128 | if (bh->idle) { | |
129 | /* idle bottom halves will be polled at least | |
130 | * every 10ms */ | |
131 | *timeout = MIN(10, *timeout); | |
132 | } else { | |
133 | /* non-idle bottom halves will be executed | |
134 | * immediately */ | |
135 | *timeout = 0; | |
136 | break; | |
137 | } | |
138 | } | |
139 | } | |
140 | } | |
141 |