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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" | |
26 | ||
27 | /***********************************************************/ | |
28 | /* bottom halves (can be seen as timers which expire ASAP) */ | |
29 | ||
30 | struct QEMUBH { | |
31 | QEMUBHFunc *cb; | |
32 | void *opaque; | |
33 | int scheduled; | |
34 | int idle; | |
35 | int deleted; | |
36 | QEMUBH *next; | |
37 | }; | |
38 | ||
39 | static QEMUBH *first_bh = NULL; | |
40 | ||
41 | QEMUBH *qemu_bh_new(QEMUBHFunc *cb, void *opaque) | |
42 | { | |
43 | QEMUBH *bh; | |
44 | bh = qemu_mallocz(sizeof(QEMUBH)); | |
45 | bh->cb = cb; | |
46 | bh->opaque = opaque; | |
47 | bh->next = first_bh; | |
48 | first_bh = bh; | |
49 | return bh; | |
50 | } | |
51 | ||
52 | int qemu_bh_poll(void) | |
53 | { | |
54 | QEMUBH *bh, **bhp; | |
55 | int ret; | |
56 | ||
57 | ret = 0; | |
58 | for (bh = first_bh; bh; bh = bh->next) { | |
59 | if (!bh->deleted && bh->scheduled) { | |
60 | bh->scheduled = 0; | |
61 | if (!bh->idle) | |
62 | ret = 1; | |
63 | bh->idle = 0; | |
64 | bh->cb(bh->opaque); | |
65 | } | |
66 | } | |
67 | ||
68 | /* remove deleted bhs */ | |
69 | bhp = &first_bh; | |
70 | while (*bhp) { | |
71 | bh = *bhp; | |
72 | if (bh->deleted) { | |
73 | *bhp = bh->next; | |
74 | qemu_free(bh); | |
75 | } else | |
76 | bhp = &bh->next; | |
77 | } | |
78 | ||
79 | return ret; | |
80 | } | |
81 | ||
82 | void qemu_bh_schedule_idle(QEMUBH *bh) | |
83 | { | |
84 | if (bh->scheduled) | |
85 | return; | |
86 | bh->scheduled = 1; | |
87 | bh->idle = 1; | |
88 | } | |
89 | ||
90 | void qemu_bh_schedule(QEMUBH *bh) | |
91 | { | |
92 | if (bh->scheduled) | |
93 | return; | |
94 | bh->scheduled = 1; | |
95 | bh->idle = 0; | |
96 | /* stop the currently executing CPU to execute the BH ASAP */ | |
97 | qemu_notify_event(); | |
98 | } | |
99 | ||
100 | void qemu_bh_cancel(QEMUBH *bh) | |
101 | { | |
102 | bh->scheduled = 0; | |
103 | } | |
104 | ||
105 | void qemu_bh_delete(QEMUBH *bh) | |
106 | { | |
107 | bh->scheduled = 0; | |
108 | bh->deleted = 1; | |
109 | } | |
110 | ||
111 | void qemu_bh_update_timeout(int *timeout) | |
112 | { | |
113 | QEMUBH *bh; | |
114 | ||
115 | for (bh = first_bh; bh; bh = bh->next) { | |
116 | if (!bh->deleted && bh->scheduled) { | |
117 | if (bh->idle) { | |
118 | /* idle bottom halves will be polled at least | |
119 | * every 10ms */ | |
120 | *timeout = MIN(10, *timeout); | |
121 | } else { | |
122 | /* non-idle bottom halves will be executed | |
123 | * immediately */ | |
124 | *timeout = 0; | |
125 | break; | |
126 | } | |
127 | } | |
128 | } | |
129 | } | |
130 |