mirror of https://gitee.com/openkylin/qemu.git
250 lines
6.8 KiB
C
250 lines
6.8 KiB
C
/*
|
|
* QEMU aio implementation
|
|
*
|
|
* Copyright IBM, Corp. 2008
|
|
*
|
|
* Authors:
|
|
* Anthony Liguori <aliguori@us.ibm.com>
|
|
*
|
|
* This work is licensed under the terms of the GNU GPL, version 2. See
|
|
* the COPYING file in the top-level directory.
|
|
*
|
|
* Contributions after 2012-01-13 are licensed under the terms of the
|
|
* GNU GPL, version 2 or (at your option) any later version.
|
|
*/
|
|
|
|
#include "qemu-common.h"
|
|
#include "block/block.h"
|
|
#include "qemu/queue.h"
|
|
#include "qemu/sockets.h"
|
|
|
|
struct AioHandler
|
|
{
|
|
GPollFD pfd;
|
|
IOHandler *io_read;
|
|
IOHandler *io_write;
|
|
int deleted;
|
|
int pollfds_idx;
|
|
void *opaque;
|
|
QLIST_ENTRY(AioHandler) node;
|
|
};
|
|
|
|
static AioHandler *find_aio_handler(AioContext *ctx, int fd)
|
|
{
|
|
AioHandler *node;
|
|
|
|
QLIST_FOREACH(node, &ctx->aio_handlers, node) {
|
|
if (node->pfd.fd == fd)
|
|
if (!node->deleted)
|
|
return node;
|
|
}
|
|
|
|
return NULL;
|
|
}
|
|
|
|
void aio_set_fd_handler(AioContext *ctx,
|
|
int fd,
|
|
IOHandler *io_read,
|
|
IOHandler *io_write,
|
|
void *opaque)
|
|
{
|
|
AioHandler *node;
|
|
|
|
node = find_aio_handler(ctx, fd);
|
|
|
|
/* Are we deleting the fd handler? */
|
|
if (!io_read && !io_write) {
|
|
if (node) {
|
|
g_source_remove_poll(&ctx->source, &node->pfd);
|
|
|
|
/* If the lock is held, just mark the node as deleted */
|
|
if (ctx->walking_handlers) {
|
|
node->deleted = 1;
|
|
node->pfd.revents = 0;
|
|
} else {
|
|
/* Otherwise, delete it for real. We can't just mark it as
|
|
* deleted because deleted nodes are only cleaned up after
|
|
* releasing the walking_handlers lock.
|
|
*/
|
|
QLIST_REMOVE(node, node);
|
|
g_free(node);
|
|
}
|
|
}
|
|
} else {
|
|
if (node == NULL) {
|
|
/* Alloc and insert if it's not already there */
|
|
node = g_malloc0(sizeof(AioHandler));
|
|
node->pfd.fd = fd;
|
|
QLIST_INSERT_HEAD(&ctx->aio_handlers, node, node);
|
|
|
|
g_source_add_poll(&ctx->source, &node->pfd);
|
|
}
|
|
/* Update handler with latest information */
|
|
node->io_read = io_read;
|
|
node->io_write = io_write;
|
|
node->opaque = opaque;
|
|
node->pollfds_idx = -1;
|
|
|
|
node->pfd.events = (io_read ? G_IO_IN | G_IO_HUP | G_IO_ERR : 0);
|
|
node->pfd.events |= (io_write ? G_IO_OUT | G_IO_ERR : 0);
|
|
}
|
|
|
|
aio_notify(ctx);
|
|
}
|
|
|
|
void aio_set_event_notifier(AioContext *ctx,
|
|
EventNotifier *notifier,
|
|
EventNotifierHandler *io_read)
|
|
{
|
|
aio_set_fd_handler(ctx, event_notifier_get_fd(notifier),
|
|
(IOHandler *)io_read, NULL, notifier);
|
|
}
|
|
|
|
bool aio_pending(AioContext *ctx)
|
|
{
|
|
AioHandler *node;
|
|
|
|
QLIST_FOREACH(node, &ctx->aio_handlers, node) {
|
|
int revents;
|
|
|
|
revents = node->pfd.revents & node->pfd.events;
|
|
if (revents & (G_IO_IN | G_IO_HUP | G_IO_ERR) && node->io_read) {
|
|
return true;
|
|
}
|
|
if (revents & (G_IO_OUT | G_IO_ERR) && node->io_write) {
|
|
return true;
|
|
}
|
|
}
|
|
|
|
return false;
|
|
}
|
|
|
|
bool aio_dispatch(AioContext *ctx)
|
|
{
|
|
AioHandler *node;
|
|
bool progress = false;
|
|
|
|
/*
|
|
* If there are callbacks left that have been queued, we need to call them.
|
|
* Do not call select in this case, because it is possible that the caller
|
|
* does not need a complete flush (as is the case for aio_poll loops).
|
|
*/
|
|
if (aio_bh_poll(ctx)) {
|
|
progress = true;
|
|
}
|
|
|
|
/*
|
|
* We have to walk very carefully in case aio_set_fd_handler is
|
|
* called while we're walking.
|
|
*/
|
|
node = QLIST_FIRST(&ctx->aio_handlers);
|
|
while (node) {
|
|
AioHandler *tmp;
|
|
int revents;
|
|
|
|
ctx->walking_handlers++;
|
|
|
|
revents = node->pfd.revents & node->pfd.events;
|
|
node->pfd.revents = 0;
|
|
|
|
if (!node->deleted &&
|
|
(revents & (G_IO_IN | G_IO_HUP | G_IO_ERR)) &&
|
|
node->io_read) {
|
|
node->io_read(node->opaque);
|
|
|
|
/* aio_notify() does not count as progress */
|
|
if (node->opaque != &ctx->notifier) {
|
|
progress = true;
|
|
}
|
|
}
|
|
if (!node->deleted &&
|
|
(revents & (G_IO_OUT | G_IO_ERR)) &&
|
|
node->io_write) {
|
|
node->io_write(node->opaque);
|
|
progress = true;
|
|
}
|
|
|
|
tmp = node;
|
|
node = QLIST_NEXT(node, node);
|
|
|
|
ctx->walking_handlers--;
|
|
|
|
if (!ctx->walking_handlers && tmp->deleted) {
|
|
QLIST_REMOVE(tmp, node);
|
|
g_free(tmp);
|
|
}
|
|
}
|
|
|
|
/* Run our timers */
|
|
progress |= timerlistgroup_run_timers(&ctx->tlg);
|
|
|
|
return progress;
|
|
}
|
|
|
|
bool aio_poll(AioContext *ctx, bool blocking)
|
|
{
|
|
AioHandler *node;
|
|
bool was_dispatching;
|
|
int ret;
|
|
bool progress;
|
|
|
|
was_dispatching = ctx->dispatching;
|
|
progress = false;
|
|
|
|
/* aio_notify can avoid the expensive event_notifier_set if
|
|
* everything (file descriptors, bottom halves, timers) will
|
|
* be re-evaluated before the next blocking poll(). This is
|
|
* already true when aio_poll is called with blocking == false;
|
|
* if blocking == true, it is only true after poll() returns.
|
|
*
|
|
* If we're in a nested event loop, ctx->dispatching might be true.
|
|
* In that case we can restore it just before returning, but we
|
|
* have to clear it now.
|
|
*/
|
|
aio_set_dispatching(ctx, !blocking);
|
|
|
|
ctx->walking_handlers++;
|
|
|
|
g_array_set_size(ctx->pollfds, 0);
|
|
|
|
/* fill pollfds */
|
|
QLIST_FOREACH(node, &ctx->aio_handlers, node) {
|
|
node->pollfds_idx = -1;
|
|
if (!node->deleted && node->pfd.events) {
|
|
GPollFD pfd = {
|
|
.fd = node->pfd.fd,
|
|
.events = node->pfd.events,
|
|
};
|
|
node->pollfds_idx = ctx->pollfds->len;
|
|
g_array_append_val(ctx->pollfds, pfd);
|
|
}
|
|
}
|
|
|
|
ctx->walking_handlers--;
|
|
|
|
/* wait until next event */
|
|
ret = qemu_poll_ns((GPollFD *)ctx->pollfds->data,
|
|
ctx->pollfds->len,
|
|
blocking ? aio_compute_timeout(ctx) : 0);
|
|
|
|
/* if we have any readable fds, dispatch event */
|
|
if (ret > 0) {
|
|
QLIST_FOREACH(node, &ctx->aio_handlers, node) {
|
|
if (node->pollfds_idx != -1) {
|
|
GPollFD *pfd = &g_array_index(ctx->pollfds, GPollFD,
|
|
node->pollfds_idx);
|
|
node->pfd.revents = pfd->revents;
|
|
}
|
|
}
|
|
}
|
|
|
|
/* Run dispatch even if there were no readable fds to run timers */
|
|
aio_set_dispatching(ctx, true);
|
|
if (aio_dispatch(ctx)) {
|
|
progress = true;
|
|
}
|
|
|
|
aio_set_dispatching(ctx, was_dispatching);
|
|
return progress;
|
|
}
|