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8c5135f90e
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>
97 lines
2.7 KiB
C
97 lines
2.7 KiB
C
/*
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* Coroutine-aware I/O functions
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*
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* Copyright (C) 2009-2010 Nippon Telegraph and Telephone Corporation.
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* Copyright (c) 2011, Red Hat, Inc.
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy
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* of this software and associated documentation files (the "Software"), to deal
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* in the Software without restriction, including without limitation the rights
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* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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* copies of the Software, and to permit persons to whom the Software is
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* furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in
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* all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
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* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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* THE SOFTWARE.
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*/
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#include "qemu-common.h"
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#include "qemu_socket.h"
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#include "qemu-coroutine.h"
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int coroutine_fn qemu_co_recvv(int sockfd, struct iovec *iov,
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int len, int iov_offset)
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{
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int total = 0;
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int ret;
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while (len) {
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ret = qemu_recvv(sockfd, iov, len, iov_offset + total);
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if (ret < 0) {
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if (errno == EAGAIN) {
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qemu_coroutine_yield();
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continue;
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}
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if (total == 0) {
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total = -1;
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}
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break;
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}
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if (ret == 0) {
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break;
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}
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total += ret, len -= ret;
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}
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return total;
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}
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int coroutine_fn qemu_co_sendv(int sockfd, struct iovec *iov,
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int len, int iov_offset)
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{
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int total = 0;
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int ret;
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while (len) {
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ret = qemu_sendv(sockfd, iov, len, iov_offset + total);
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if (ret < 0) {
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if (errno == EAGAIN) {
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qemu_coroutine_yield();
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continue;
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}
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if (total == 0) {
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total = -1;
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}
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break;
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}
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total += ret, len -= ret;
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}
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return total;
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}
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int coroutine_fn qemu_co_recv(int sockfd, void *buf, int len)
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{
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struct iovec iov;
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iov.iov_base = buf;
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iov.iov_len = len;
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return qemu_co_recvv(sockfd, &iov, len, 0);
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}
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int coroutine_fn qemu_co_send(int sockfd, void *buf, int len)
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{
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struct iovec iov;
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iov.iov_base = buf;
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iov.iov_len = len;
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return qemu_co_sendv(sockfd, &iov, len, 0);
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}
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