scsi: move handling of REQUEST SENSE to common code
[qemu.git] / async.c
blob3fe70b9debb37fef3d6c9d567f09a3fe1bc2881c
1 /*
2 * QEMU System Emulator
4 * Copyright (c) 2003-2008 Fabrice Bellard
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:
13 * The above copyright notice and this permission notice shall be included in
14 * all copies or substantial portions of the Software.
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.
25 #include "qemu-common.h"
26 #include "qemu-aio.h"
28 /* Anchor of the list of Bottom Halves belonging to the context */
29 static struct QEMUBH *first_bh;
31 /***********************************************************/
32 /* bottom halves (can be seen as timers which expire ASAP) */
34 struct QEMUBH {
35 QEMUBHFunc *cb;
36 void *opaque;
37 int scheduled;
38 int idle;
39 int deleted;
40 QEMUBH *next;
43 QEMUBH *qemu_bh_new(QEMUBHFunc *cb, void *opaque)
45 QEMUBH *bh;
46 bh = qemu_mallocz(sizeof(QEMUBH));
47 bh->cb = cb;
48 bh->opaque = opaque;
49 bh->next = first_bh;
50 first_bh = bh;
51 return bh;
54 int qemu_bh_poll(void)
56 QEMUBH *bh, **bhp, *next;
57 int ret;
59 ret = 0;
60 for (bh = first_bh; bh; bh = next) {
61 next = bh->next;
62 if (!bh->deleted && bh->scheduled) {
63 bh->scheduled = 0;
64 if (!bh->idle)
65 ret = 1;
66 bh->idle = 0;
67 bh->cb(bh->opaque);
71 /* remove deleted bhs */
72 bhp = &first_bh;
73 while (*bhp) {
74 bh = *bhp;
75 if (bh->deleted) {
76 *bhp = bh->next;
77 qemu_free(bh);
78 } else
79 bhp = &bh->next;
82 return ret;
85 void qemu_bh_schedule_idle(QEMUBH *bh)
87 if (bh->scheduled)
88 return;
89 bh->scheduled = 1;
90 bh->idle = 1;
93 void qemu_bh_schedule(QEMUBH *bh)
95 if (bh->scheduled)
96 return;
97 bh->scheduled = 1;
98 bh->idle = 0;
99 /* stop the currently executing CPU to execute the BH ASAP */
100 qemu_notify_event();
103 void qemu_bh_cancel(QEMUBH *bh)
105 bh->scheduled = 0;
108 void qemu_bh_delete(QEMUBH *bh)
110 bh->scheduled = 0;
111 bh->deleted = 1;
114 void qemu_bh_update_timeout(int *timeout)
116 QEMUBH *bh;
118 for (bh = first_bh; bh; bh = bh->next) {
119 if (!bh->deleted && bh->scheduled) {
120 if (bh->idle) {
121 /* idle bottom halves will be polled at least
122 * every 10ms */
123 *timeout = MIN(10, *timeout);
124 } else {
125 /* non-idle bottom halves will be executed
126 * immediately */
127 *timeout = 0;
128 break;