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/*
* QEMU System Emulator
*
* Copyright (c) 2003-2008 Fabrice Bellard
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
#include "qemu-common.h"
#include "qemu-aio.h"
#include "main-loop.h"
/* Anchor of the list of Bottom Halves belonging to the context */
static struct QEMUBH *first_bh;
/***********************************************************/
/* bottom halves (can be seen as timers which expire ASAP) */
struct QEMUBH {
QEMUBHFunc *cb;
void *opaque;
QEMUBH *next;
bool scheduled;
bool idle;
bool deleted;
};
QEMUBH *qemu_bh_new(QEMUBHFunc *cb, void *opaque)
{
QEMUBH *bh;
bh = g_malloc0(sizeof(QEMUBH));
bh->cb = cb;
bh->opaque = opaque;
bh->next = first_bh;
first_bh = bh;
return bh;
}
int qemu_bh_poll(void)
{
QEMUBH *bh, **bhp, *next;
int ret;
static int nesting = 0;
nesting++;
ret = 0;
for (bh = first_bh; bh; bh = next) {
next = bh->next;
if (!bh->deleted && bh->scheduled) {
bh->scheduled = 0;
if (!bh->idle)
ret = 1;
bh->idle = 0;
bh->cb(bh->opaque);
}
}
nesting--;
/* remove deleted bhs */
if (!nesting) {
bhp = &first_bh;
while (*bhp) {
bh = *bhp;
if (bh->deleted) {
*bhp = bh->next;
g_free(bh);
} else {
bhp = &bh->next;
}
}
}
return ret;
}
void qemu_bh_schedule_idle(QEMUBH *bh)
{
if (bh->scheduled)
return;
bh->scheduled = 1;
bh->idle = 1;
}
void qemu_bh_schedule(QEMUBH *bh)
{
if (bh->scheduled)
return;
bh->scheduled = 1;
bh->idle = 0;
/* stop the currently executing CPU to execute the BH ASAP */
qemu_notify_event();
}
void qemu_bh_cancel(QEMUBH *bh)
{
bh->scheduled = 0;
}
void qemu_bh_delete(QEMUBH *bh)
{
bh->scheduled = 0;
bh->deleted = 1;
}
void qemu_bh_update_timeout(uint32_t *timeout)
{
QEMUBH *bh;
for (bh = first_bh; bh; bh = bh->next) {
if (!bh->deleted && bh->scheduled) {
if (bh->idle) {
/* idle bottom halves will be polled at least
* every 10ms */
*timeout = MIN(10, *timeout);
} else {
/* non-idle bottom halves will be executed
* immediately */
*timeout = 0;
break;
}
}
}
}
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