qemu/qemu-coroutine-io.c
Paolo Bonzini 8c5135f90e sheepdog: move coroutine send/recv function to generic code
Outside coroutines, avoid busy waiting on EAGAIN by temporarily
making the socket blocking.

The API of qemu_recvv/qemu_sendv is slightly different from
do_readv/do_writev because they do not handle coroutines.  It
returns the number of bytes written before encountering an
EAGAIN.  The specificity of yielding on EAGAIN is entirely in
qemu-coroutine.c.

Reviewed-by: MORITA Kazutaka <morita.kazutaka@lab.ntt.co.jp>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2011-12-22 11:53:53 +01:00

97 lines
2.7 KiB
C

/*
* Coroutine-aware I/O functions
*
* Copyright (C) 2009-2010 Nippon Telegraph and Telephone Corporation.
* Copyright (c) 2011, Red Hat, Inc.
*
* 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_socket.h"
#include "qemu-coroutine.h"
int coroutine_fn qemu_co_recvv(int sockfd, struct iovec *iov,
int len, int iov_offset)
{
int total = 0;
int ret;
while (len) {
ret = qemu_recvv(sockfd, iov, len, iov_offset + total);
if (ret < 0) {
if (errno == EAGAIN) {
qemu_coroutine_yield();
continue;
}
if (total == 0) {
total = -1;
}
break;
}
if (ret == 0) {
break;
}
total += ret, len -= ret;
}
return total;
}
int coroutine_fn qemu_co_sendv(int sockfd, struct iovec *iov,
int len, int iov_offset)
{
int total = 0;
int ret;
while (len) {
ret = qemu_sendv(sockfd, iov, len, iov_offset + total);
if (ret < 0) {
if (errno == EAGAIN) {
qemu_coroutine_yield();
continue;
}
if (total == 0) {
total = -1;
}
break;
}
total += ret, len -= ret;
}
return total;
}
int coroutine_fn qemu_co_recv(int sockfd, void *buf, int len)
{
struct iovec iov;
iov.iov_base = buf;
iov.iov_len = len;
return qemu_co_recvv(sockfd, &iov, len, 0);
}
int coroutine_fn qemu_co_send(int sockfd, void *buf, int len)
{
struct iovec iov;
iov.iov_base = buf;
iov.iov_len = len;
return qemu_co_sendv(sockfd, &iov, len, 0);
}