qemu/io/channel.c
Paolo Bonzini c4c497d27f io: make qio_channel_yield aware of AioContexts
Support separate coroutines for reading and writing, and place the
read/write handlers on the AioContext that the QIOChannel is registered
with.

Reviewed-by: Daniel P. Berrange <berrange@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Fam Zheng <famz@redhat.com>
Message-id: 20170213135235.12274-7-pbonzini@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2017-02-21 11:14:07 +00:00

384 lines
9.8 KiB
C

/*
* QEMU I/O channels
*
* Copyright (c) 2015 Red Hat, Inc.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, see <http://www.gnu.org/licenses/>.
*
*/
#include "qemu/osdep.h"
#include "io/channel.h"
#include "qapi/error.h"
#include "qemu/main-loop.h"
bool qio_channel_has_feature(QIOChannel *ioc,
QIOChannelFeature feature)
{
return ioc->features & (1 << feature);
}
void qio_channel_set_feature(QIOChannel *ioc,
QIOChannelFeature feature)
{
ioc->features |= (1 << feature);
}
void qio_channel_set_name(QIOChannel *ioc,
const char *name)
{
g_free(ioc->name);
ioc->name = g_strdup(name);
}
ssize_t qio_channel_readv_full(QIOChannel *ioc,
const struct iovec *iov,
size_t niov,
int **fds,
size_t *nfds,
Error **errp)
{
QIOChannelClass *klass = QIO_CHANNEL_GET_CLASS(ioc);
if ((fds || nfds) &&
!qio_channel_has_feature(ioc, QIO_CHANNEL_FEATURE_FD_PASS)) {
error_setg_errno(errp, EINVAL,
"Channel does not support file descriptor passing");
return -1;
}
return klass->io_readv(ioc, iov, niov, fds, nfds, errp);
}
ssize_t qio_channel_writev_full(QIOChannel *ioc,
const struct iovec *iov,
size_t niov,
int *fds,
size_t nfds,
Error **errp)
{
QIOChannelClass *klass = QIO_CHANNEL_GET_CLASS(ioc);
if ((fds || nfds) &&
!qio_channel_has_feature(ioc, QIO_CHANNEL_FEATURE_FD_PASS)) {
error_setg_errno(errp, EINVAL,
"Channel does not support file descriptor passing");
return -1;
}
return klass->io_writev(ioc, iov, niov, fds, nfds, errp);
}
ssize_t qio_channel_readv(QIOChannel *ioc,
const struct iovec *iov,
size_t niov,
Error **errp)
{
return qio_channel_readv_full(ioc, iov, niov, NULL, NULL, errp);
}
ssize_t qio_channel_writev(QIOChannel *ioc,
const struct iovec *iov,
size_t niov,
Error **errp)
{
return qio_channel_writev_full(ioc, iov, niov, NULL, 0, errp);
}
ssize_t qio_channel_read(QIOChannel *ioc,
char *buf,
size_t buflen,
Error **errp)
{
struct iovec iov = { .iov_base = buf, .iov_len = buflen };
return qio_channel_readv_full(ioc, &iov, 1, NULL, NULL, errp);
}
ssize_t qio_channel_write(QIOChannel *ioc,
const char *buf,
size_t buflen,
Error **errp)
{
struct iovec iov = { .iov_base = (char *)buf, .iov_len = buflen };
return qio_channel_writev_full(ioc, &iov, 1, NULL, 0, errp);
}
int qio_channel_set_blocking(QIOChannel *ioc,
bool enabled,
Error **errp)
{
QIOChannelClass *klass = QIO_CHANNEL_GET_CLASS(ioc);
return klass->io_set_blocking(ioc, enabled, errp);
}
int qio_channel_close(QIOChannel *ioc,
Error **errp)
{
QIOChannelClass *klass = QIO_CHANNEL_GET_CLASS(ioc);
return klass->io_close(ioc, errp);
}
GSource *qio_channel_create_watch(QIOChannel *ioc,
GIOCondition condition)
{
QIOChannelClass *klass = QIO_CHANNEL_GET_CLASS(ioc);
GSource *ret = klass->io_create_watch(ioc, condition);
if (ioc->name) {
g_source_set_name(ret, ioc->name);
}
return ret;
}
void qio_channel_set_aio_fd_handler(QIOChannel *ioc,
AioContext *ctx,
IOHandler *io_read,
IOHandler *io_write,
void *opaque)
{
QIOChannelClass *klass = QIO_CHANNEL_GET_CLASS(ioc);
klass->io_set_aio_fd_handler(ioc, ctx, io_read, io_write, opaque);
}
guint qio_channel_add_watch(QIOChannel *ioc,
GIOCondition condition,
QIOChannelFunc func,
gpointer user_data,
GDestroyNotify notify)
{
GSource *source;
guint id;
source = qio_channel_create_watch(ioc, condition);
g_source_set_callback(source, (GSourceFunc)func, user_data, notify);
id = g_source_attach(source, NULL);
g_source_unref(source);
return id;
}
int qio_channel_shutdown(QIOChannel *ioc,
QIOChannelShutdown how,
Error **errp)
{
QIOChannelClass *klass = QIO_CHANNEL_GET_CLASS(ioc);
if (!klass->io_shutdown) {
error_setg(errp, "Data path shutdown not supported");
return -1;
}
return klass->io_shutdown(ioc, how, errp);
}
void qio_channel_set_delay(QIOChannel *ioc,
bool enabled)
{
QIOChannelClass *klass = QIO_CHANNEL_GET_CLASS(ioc);
if (klass->io_set_delay) {
klass->io_set_delay(ioc, enabled);
}
}
void qio_channel_set_cork(QIOChannel *ioc,
bool enabled)
{
QIOChannelClass *klass = QIO_CHANNEL_GET_CLASS(ioc);
if (klass->io_set_cork) {
klass->io_set_cork(ioc, enabled);
}
}
off_t qio_channel_io_seek(QIOChannel *ioc,
off_t offset,
int whence,
Error **errp)
{
QIOChannelClass *klass = QIO_CHANNEL_GET_CLASS(ioc);
if (!klass->io_seek) {
error_setg(errp, "Channel does not support random access");
return -1;
}
return klass->io_seek(ioc, offset, whence, errp);
}
static void qio_channel_set_aio_fd_handlers(QIOChannel *ioc);
static void qio_channel_restart_read(void *opaque)
{
QIOChannel *ioc = opaque;
Coroutine *co = ioc->read_coroutine;
ioc->read_coroutine = NULL;
qio_channel_set_aio_fd_handlers(ioc);
aio_co_wake(co);
}
static void qio_channel_restart_write(void *opaque)
{
QIOChannel *ioc = opaque;
Coroutine *co = ioc->write_coroutine;
ioc->write_coroutine = NULL;
qio_channel_set_aio_fd_handlers(ioc);
aio_co_wake(co);
}
static void qio_channel_set_aio_fd_handlers(QIOChannel *ioc)
{
IOHandler *rd_handler = NULL, *wr_handler = NULL;
AioContext *ctx;
if (ioc->read_coroutine) {
rd_handler = qio_channel_restart_read;
}
if (ioc->write_coroutine) {
wr_handler = qio_channel_restart_write;
}
ctx = ioc->ctx ? ioc->ctx : iohandler_get_aio_context();
qio_channel_set_aio_fd_handler(ioc, ctx, rd_handler, wr_handler, ioc);
}
void qio_channel_attach_aio_context(QIOChannel *ioc,
AioContext *ctx)
{
AioContext *old_ctx;
if (ioc->ctx == ctx) {
return;
}
old_ctx = ioc->ctx ? ioc->ctx : iohandler_get_aio_context();
qio_channel_set_aio_fd_handler(ioc, old_ctx, NULL, NULL, NULL);
ioc->ctx = ctx;
qio_channel_set_aio_fd_handlers(ioc);
}
void qio_channel_detach_aio_context(QIOChannel *ioc)
{
ioc->read_coroutine = NULL;
ioc->write_coroutine = NULL;
qio_channel_set_aio_fd_handlers(ioc);
ioc->ctx = NULL;
}
void coroutine_fn qio_channel_yield(QIOChannel *ioc,
GIOCondition condition)
{
assert(qemu_in_coroutine());
if (condition == G_IO_IN) {
assert(!ioc->read_coroutine);
ioc->read_coroutine = qemu_coroutine_self();
} else if (condition == G_IO_OUT) {
assert(!ioc->write_coroutine);
ioc->write_coroutine = qemu_coroutine_self();
} else {
abort();
}
qio_channel_set_aio_fd_handlers(ioc);
qemu_coroutine_yield();
}
static gboolean qio_channel_wait_complete(QIOChannel *ioc,
GIOCondition condition,
gpointer opaque)
{
GMainLoop *loop = opaque;
g_main_loop_quit(loop);
return FALSE;
}
void qio_channel_wait(QIOChannel *ioc,
GIOCondition condition)
{
GMainContext *ctxt = g_main_context_new();
GMainLoop *loop = g_main_loop_new(ctxt, TRUE);
GSource *source;
source = qio_channel_create_watch(ioc, condition);
g_source_set_callback(source,
(GSourceFunc)qio_channel_wait_complete,
loop,
NULL);
g_source_attach(source, ctxt);
g_main_loop_run(loop);
g_source_unref(source);
g_main_loop_unref(loop);
g_main_context_unref(ctxt);
}
static void qio_channel_finalize(Object *obj)
{
QIOChannel *ioc = QIO_CHANNEL(obj);
g_free(ioc->name);
#ifdef _WIN32
if (ioc->event) {
CloseHandle(ioc->event);
}
#endif
}
static const TypeInfo qio_channel_info = {
.parent = TYPE_OBJECT,
.name = TYPE_QIO_CHANNEL,
.instance_size = sizeof(QIOChannel),
.instance_finalize = qio_channel_finalize,
.abstract = true,
.class_size = sizeof(QIOChannelClass),
};
static void qio_channel_register_types(void)
{
type_register_static(&qio_channel_info);
}
type_init(qio_channel_register_types);