98 lines
3.1 KiB
Diff
98 lines
3.1 KiB
Diff
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From 52d73aa49799848042c09be1c64c1bff2159a5e1 Mon Sep 17 00:00:00 2001
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From: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
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Date: Mon, 20 Aug 2012 10:14:35 +0100
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Subject: [PATCH] net: EAGAIN handling for net/socket.c TCP
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Replace spinning send_all() with a proper non-blocking send. When the
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socket write buffer limit is reached, we should stop trying to send and
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wait for the socket to become writable again.
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Non-blocking TCP sockets can return in two different ways when the write
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buffer limit is reached:
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1. ret = -1 and errno = EAGAIN/EWOULDBLOCK. No data has been written.
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2. ret < total_size. Short write, only part of the message was
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transmitted.
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Handle both cases and keep track of how many bytes have been written in
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s->send_index. (This includes the 'length' header before the actual
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payload buffer.)
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Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
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(cherry picked from commit 45a7f54a8bb3928ffa58d522e0d61acaee8277bb)
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Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
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---
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net/socket.c | 36 +++++++++++++++++++++++++++++++-----
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1 file changed, 31 insertions(+), 5 deletions(-)
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diff --git a/net/socket.c b/net/socket.c
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index e5e4e8d..c3e55b8 100644
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--- a/net/socket.c
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+++ b/net/socket.c
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@@ -32,6 +32,7 @@
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#include "qemu-error.h"
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#include "qemu-option.h"
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#include "qemu_socket.h"
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+#include "iov.h"
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typedef struct NetSocketState {
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NetClientState nc;
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@@ -40,6 +41,7 @@ typedef struct NetSocketState {
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int state; /* 0 = getting length, 1 = getting data */
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unsigned int index;
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unsigned int packet_len;
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+ unsigned int send_index; /* number of bytes sent (only SOCK_STREAM) */
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uint8_t buf[4096];
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struct sockaddr_in dgram_dst; /* contains inet host and port destination iff connectionless (SOCK_DGRAM) */
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IOHandler *send_fn; /* differs between SOCK_STREAM/SOCK_DGRAM */
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@@ -88,15 +90,39 @@ static void net_socket_writable(void *opaque)
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qemu_flush_queued_packets(&s->nc);
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}
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-/* XXX: we consider we can send the whole packet without blocking */
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static ssize_t net_socket_receive(NetClientState *nc, const uint8_t *buf, size_t size)
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{
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NetSocketState *s = DO_UPCAST(NetSocketState, nc, nc);
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- uint32_t len;
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- len = htonl(size);
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+ uint32_t len = htonl(size);
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+ struct iovec iov[] = {
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+ {
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+ .iov_base = &len,
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+ .iov_len = sizeof(len),
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+ }, {
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+ .iov_base = (void *)buf,
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+ .iov_len = size,
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+ },
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+ };
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+ size_t remaining;
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+ ssize_t ret;
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+
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+ remaining = iov_size(iov, 2) - s->send_index;
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+ ret = iov_send(s->fd, iov, 2, s->send_index, remaining);
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- send_all(s->fd, (const uint8_t *)&len, sizeof(len));
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- return send_all(s->fd, buf, size);
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+ if (ret == -1 && errno == EAGAIN) {
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+ ret = 0; /* handled further down */
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+ }
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+ if (ret == -1) {
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+ s->send_index = 0;
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+ return -errno;
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+ }
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+ if (ret < (ssize_t)remaining) {
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+ s->send_index += ret;
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+ net_socket_write_poll(s, true);
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+ return 0;
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+ }
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+ s->send_index = 0;
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+ return size;
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}
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static ssize_t net_socket_receive_dgram(NetClientState *nc, const uint8_t *buf, size_t size)
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--
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1.7.12.1
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