xemu/nbd/common.c
Paolo Bonzini ff82911cd3 nbd: convert to use qio_channel_yield
In the client, read the reply headers from a coroutine, switching the
read side between the "read header" coroutine and the I/O coroutine that
reads the body of the reply.

In the server, if the server can read more requests it will create a new
"read request" coroutine as soon as a request has been read.  Otherwise,
the new coroutine is created in nbd_request_put.

Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Fam Zheng <famz@redhat.com>
Reviewed-by: Daniel P. Berrange <berrange@redhat.com>
Message-id: 20170213135235.12274-8-pbonzini@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2017-02-21 11:14:08 +00:00

85 lines
2.4 KiB
C

/*
* Copyright (C) 2005 Anthony Liguori <anthony@codemonkey.ws>
*
* Network Block Device Common Code
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; under version 2 of the License.
*
* This program 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 General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, see <http://www.gnu.org/licenses/>.
*/
#include "qemu/osdep.h"
#include "qapi/error.h"
#include "nbd-internal.h"
ssize_t nbd_wr_syncv(QIOChannel *ioc,
struct iovec *iov,
size_t niov,
size_t length,
bool do_read)
{
ssize_t done = 0;
Error *local_err = NULL;
struct iovec *local_iov = g_new(struct iovec, niov);
struct iovec *local_iov_head = local_iov;
unsigned int nlocal_iov = niov;
nlocal_iov = iov_copy(local_iov, nlocal_iov, iov, niov, 0, length);
while (nlocal_iov > 0) {
ssize_t len;
if (do_read) {
len = qio_channel_readv(ioc, local_iov, nlocal_iov, &local_err);
} else {
len = qio_channel_writev(ioc, local_iov, nlocal_iov, &local_err);
}
if (len == QIO_CHANNEL_ERR_BLOCK) {
if (qemu_in_coroutine()) {
qio_channel_yield(ioc, do_read ? G_IO_IN : G_IO_OUT);
} else {
return -EAGAIN;
}
continue;
}
if (len < 0) {
TRACE("I/O error: %s", error_get_pretty(local_err));
error_free(local_err);
/* XXX handle Error objects */
done = -EIO;
goto cleanup;
}
if (do_read && len == 0) {
break;
}
iov_discard_front(&local_iov, &nlocal_iov, len);
done += len;
}
cleanup:
g_free(local_iov_head);
return done;
}
void nbd_tls_handshake(QIOTask *task,
void *opaque)
{
struct NBDTLSHandshakeData *data = opaque;
if (qio_task_propagate_error(task, &data->error)) {
TRACE("TLS failed %s", error_get_pretty(data->error));
}
data->complete = true;
g_main_loop_quit(data->loop);
}