439 lines
11 KiB
C
439 lines
11 KiB
C
/*
|
|
* VMware vSockets Driver
|
|
*
|
|
* Copyright (C) 2009-2013 VMware, Inc. All rights reserved.
|
|
*
|
|
* 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 version 2 and no later version.
|
|
*
|
|
* 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.
|
|
*/
|
|
|
|
#include <linux/types.h>
|
|
#include <linux/socket.h>
|
|
#include <linux/stddef.h>
|
|
#include <net/sock.h>
|
|
|
|
#include "vmci_transport_notify.h"
|
|
|
|
#define PKT_FIELD(vsk, field_name) \
|
|
(vmci_trans(vsk)->notify.pkt_q_state.field_name)
|
|
|
|
static bool vmci_transport_notify_waiting_write(struct vsock_sock *vsk)
|
|
{
|
|
bool retval;
|
|
u64 notify_limit;
|
|
|
|
if (!PKT_FIELD(vsk, peer_waiting_write))
|
|
return false;
|
|
|
|
/* When the sender blocks, we take that as a sign that the sender is
|
|
* faster than the receiver. To reduce the transmit rate of the sender,
|
|
* we delay the sending of the read notification by decreasing the
|
|
* write_notify_window. The notification is delayed until the number of
|
|
* bytes used in the queue drops below the write_notify_window.
|
|
*/
|
|
|
|
if (!PKT_FIELD(vsk, peer_waiting_write_detected)) {
|
|
PKT_FIELD(vsk, peer_waiting_write_detected) = true;
|
|
if (PKT_FIELD(vsk, write_notify_window) < PAGE_SIZE) {
|
|
PKT_FIELD(vsk, write_notify_window) =
|
|
PKT_FIELD(vsk, write_notify_min_window);
|
|
} else {
|
|
PKT_FIELD(vsk, write_notify_window) -= PAGE_SIZE;
|
|
if (PKT_FIELD(vsk, write_notify_window) <
|
|
PKT_FIELD(vsk, write_notify_min_window))
|
|
PKT_FIELD(vsk, write_notify_window) =
|
|
PKT_FIELD(vsk, write_notify_min_window);
|
|
|
|
}
|
|
}
|
|
notify_limit = vmci_trans(vsk)->consume_size -
|
|
PKT_FIELD(vsk, write_notify_window);
|
|
|
|
/* The notify_limit is used to delay notifications in the case where
|
|
* flow control is enabled. Below the test is expressed in terms of
|
|
* free space in the queue: if free_space > ConsumeSize -
|
|
* write_notify_window then notify An alternate way of expressing this
|
|
* is to rewrite the expression to use the data ready in the receive
|
|
* queue: if write_notify_window > bufferReady then notify as
|
|
* free_space == ConsumeSize - bufferReady.
|
|
*/
|
|
|
|
retval = vmci_qpair_consume_free_space(vmci_trans(vsk)->qpair) >
|
|
notify_limit;
|
|
|
|
if (retval) {
|
|
/* Once we notify the peer, we reset the detected flag so the
|
|
* next wait will again cause a decrease in the window size.
|
|
*/
|
|
|
|
PKT_FIELD(vsk, peer_waiting_write_detected) = false;
|
|
}
|
|
return retval;
|
|
}
|
|
|
|
static void
|
|
vmci_transport_handle_read(struct sock *sk,
|
|
struct vmci_transport_packet *pkt,
|
|
bool bottom_half,
|
|
struct sockaddr_vm *dst, struct sockaddr_vm *src)
|
|
{
|
|
sk->sk_write_space(sk);
|
|
}
|
|
|
|
static void
|
|
vmci_transport_handle_wrote(struct sock *sk,
|
|
struct vmci_transport_packet *pkt,
|
|
bool bottom_half,
|
|
struct sockaddr_vm *dst, struct sockaddr_vm *src)
|
|
{
|
|
sk->sk_data_ready(sk, 0);
|
|
}
|
|
|
|
static void vsock_block_update_write_window(struct sock *sk)
|
|
{
|
|
struct vsock_sock *vsk = vsock_sk(sk);
|
|
|
|
if (PKT_FIELD(vsk, write_notify_window) < vmci_trans(vsk)->consume_size)
|
|
PKT_FIELD(vsk, write_notify_window) =
|
|
min(PKT_FIELD(vsk, write_notify_window) + PAGE_SIZE,
|
|
vmci_trans(vsk)->consume_size);
|
|
}
|
|
|
|
static int vmci_transport_send_read_notification(struct sock *sk)
|
|
{
|
|
struct vsock_sock *vsk;
|
|
bool sent_read;
|
|
unsigned int retries;
|
|
int err;
|
|
|
|
vsk = vsock_sk(sk);
|
|
sent_read = false;
|
|
retries = 0;
|
|
err = 0;
|
|
|
|
if (vmci_transport_notify_waiting_write(vsk)) {
|
|
/* Notify the peer that we have read, retrying the send on
|
|
* failure up to our maximum value. XXX For now we just log
|
|
* the failure, but later we should schedule a work item to
|
|
* handle the resend until it succeeds. That would require
|
|
* keeping track of work items in the vsk and cleaning them up
|
|
* upon socket close.
|
|
*/
|
|
while (!(vsk->peer_shutdown & RCV_SHUTDOWN) &&
|
|
!sent_read &&
|
|
retries < VMCI_TRANSPORT_MAX_DGRAM_RESENDS) {
|
|
err = vmci_transport_send_read(sk);
|
|
if (err >= 0)
|
|
sent_read = true;
|
|
|
|
retries++;
|
|
}
|
|
|
|
if (retries >= VMCI_TRANSPORT_MAX_DGRAM_RESENDS && !sent_read)
|
|
pr_err("%p unable to send read notification to peer\n",
|
|
sk);
|
|
else
|
|
PKT_FIELD(vsk, peer_waiting_write) = false;
|
|
|
|
}
|
|
return err;
|
|
}
|
|
|
|
static void vmci_transport_notify_pkt_socket_init(struct sock *sk)
|
|
{
|
|
struct vsock_sock *vsk = vsock_sk(sk);
|
|
|
|
PKT_FIELD(vsk, write_notify_window) = PAGE_SIZE;
|
|
PKT_FIELD(vsk, write_notify_min_window) = PAGE_SIZE;
|
|
PKT_FIELD(vsk, peer_waiting_write) = false;
|
|
PKT_FIELD(vsk, peer_waiting_write_detected) = false;
|
|
}
|
|
|
|
static void vmci_transport_notify_pkt_socket_destruct(struct vsock_sock *vsk)
|
|
{
|
|
PKT_FIELD(vsk, write_notify_window) = PAGE_SIZE;
|
|
PKT_FIELD(vsk, write_notify_min_window) = PAGE_SIZE;
|
|
PKT_FIELD(vsk, peer_waiting_write) = false;
|
|
PKT_FIELD(vsk, peer_waiting_write_detected) = false;
|
|
}
|
|
|
|
static int
|
|
vmci_transport_notify_pkt_poll_in(struct sock *sk,
|
|
size_t target, bool *data_ready_now)
|
|
{
|
|
struct vsock_sock *vsk = vsock_sk(sk);
|
|
|
|
if (vsock_stream_has_data(vsk)) {
|
|
*data_ready_now = true;
|
|
} else {
|
|
/* We can't read right now because there is nothing in the
|
|
* queue. Ask for notifications when there is something to
|
|
* read.
|
|
*/
|
|
if (sk->sk_state == SS_CONNECTED)
|
|
vsock_block_update_write_window(sk);
|
|
*data_ready_now = false;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int
|
|
vmci_transport_notify_pkt_poll_out(struct sock *sk,
|
|
size_t target, bool *space_avail_now)
|
|
{
|
|
s64 produce_q_free_space;
|
|
struct vsock_sock *vsk = vsock_sk(sk);
|
|
|
|
produce_q_free_space = vsock_stream_has_space(vsk);
|
|
if (produce_q_free_space > 0) {
|
|
*space_avail_now = true;
|
|
return 0;
|
|
} else if (produce_q_free_space == 0) {
|
|
/* This is a connected socket but we can't currently send data.
|
|
* Nothing else to do.
|
|
*/
|
|
*space_avail_now = false;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int
|
|
vmci_transport_notify_pkt_recv_init(
|
|
struct sock *sk,
|
|
size_t target,
|
|
struct vmci_transport_recv_notify_data *data)
|
|
{
|
|
struct vsock_sock *vsk = vsock_sk(sk);
|
|
|
|
data->consume_head = 0;
|
|
data->produce_tail = 0;
|
|
data->notify_on_block = false;
|
|
|
|
if (PKT_FIELD(vsk, write_notify_min_window) < target + 1) {
|
|
PKT_FIELD(vsk, write_notify_min_window) = target + 1;
|
|
if (PKT_FIELD(vsk, write_notify_window) <
|
|
PKT_FIELD(vsk, write_notify_min_window)) {
|
|
/* If the current window is smaller than the new
|
|
* minimal window size, we need to reevaluate whether
|
|
* we need to notify the sender. If the number of ready
|
|
* bytes are smaller than the new window, we need to
|
|
* send a notification to the sender before we block.
|
|
*/
|
|
|
|
PKT_FIELD(vsk, write_notify_window) =
|
|
PKT_FIELD(vsk, write_notify_min_window);
|
|
data->notify_on_block = true;
|
|
}
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int
|
|
vmci_transport_notify_pkt_recv_pre_block(
|
|
struct sock *sk,
|
|
size_t target,
|
|
struct vmci_transport_recv_notify_data *data)
|
|
{
|
|
int err = 0;
|
|
|
|
vsock_block_update_write_window(sk);
|
|
|
|
if (data->notify_on_block) {
|
|
err = vmci_transport_send_read_notification(sk);
|
|
if (err < 0)
|
|
return err;
|
|
data->notify_on_block = false;
|
|
}
|
|
|
|
return err;
|
|
}
|
|
|
|
static int
|
|
vmci_transport_notify_pkt_recv_post_dequeue(
|
|
struct sock *sk,
|
|
size_t target,
|
|
ssize_t copied,
|
|
bool data_read,
|
|
struct vmci_transport_recv_notify_data *data)
|
|
{
|
|
struct vsock_sock *vsk;
|
|
int err;
|
|
bool was_full = false;
|
|
u64 free_space;
|
|
|
|
vsk = vsock_sk(sk);
|
|
err = 0;
|
|
|
|
if (data_read) {
|
|
smp_mb();
|
|
|
|
free_space =
|
|
vmci_qpair_consume_free_space(vmci_trans(vsk)->qpair);
|
|
was_full = free_space == copied;
|
|
|
|
if (was_full)
|
|
PKT_FIELD(vsk, peer_waiting_write) = true;
|
|
|
|
err = vmci_transport_send_read_notification(sk);
|
|
if (err < 0)
|
|
return err;
|
|
|
|
/* See the comment in
|
|
* vmci_transport_notify_pkt_send_post_enqueue().
|
|
*/
|
|
sk->sk_data_ready(sk, 0);
|
|
}
|
|
|
|
return err;
|
|
}
|
|
|
|
static int
|
|
vmci_transport_notify_pkt_send_init(
|
|
struct sock *sk,
|
|
struct vmci_transport_send_notify_data *data)
|
|
{
|
|
data->consume_head = 0;
|
|
data->produce_tail = 0;
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int
|
|
vmci_transport_notify_pkt_send_post_enqueue(
|
|
struct sock *sk,
|
|
ssize_t written,
|
|
struct vmci_transport_send_notify_data *data)
|
|
{
|
|
int err = 0;
|
|
struct vsock_sock *vsk;
|
|
bool sent_wrote = false;
|
|
bool was_empty;
|
|
int retries = 0;
|
|
|
|
vsk = vsock_sk(sk);
|
|
|
|
smp_mb();
|
|
|
|
was_empty =
|
|
vmci_qpair_produce_buf_ready(vmci_trans(vsk)->qpair) == written;
|
|
if (was_empty) {
|
|
while (!(vsk->peer_shutdown & RCV_SHUTDOWN) &&
|
|
!sent_wrote &&
|
|
retries < VMCI_TRANSPORT_MAX_DGRAM_RESENDS) {
|
|
err = vmci_transport_send_wrote(sk);
|
|
if (err >= 0)
|
|
sent_wrote = true;
|
|
|
|
retries++;
|
|
}
|
|
}
|
|
|
|
if (retries >= VMCI_TRANSPORT_MAX_DGRAM_RESENDS && !sent_wrote) {
|
|
pr_err("%p unable to send wrote notification to peer\n",
|
|
sk);
|
|
return err;
|
|
}
|
|
|
|
return err;
|
|
}
|
|
|
|
static void
|
|
vmci_transport_notify_pkt_handle_pkt(
|
|
struct sock *sk,
|
|
struct vmci_transport_packet *pkt,
|
|
bool bottom_half,
|
|
struct sockaddr_vm *dst,
|
|
struct sockaddr_vm *src, bool *pkt_processed)
|
|
{
|
|
bool processed = false;
|
|
|
|
switch (pkt->type) {
|
|
case VMCI_TRANSPORT_PACKET_TYPE_WROTE:
|
|
vmci_transport_handle_wrote(sk, pkt, bottom_half, dst, src);
|
|
processed = true;
|
|
break;
|
|
case VMCI_TRANSPORT_PACKET_TYPE_READ:
|
|
vmci_transport_handle_read(sk, pkt, bottom_half, dst, src);
|
|
processed = true;
|
|
break;
|
|
}
|
|
|
|
if (pkt_processed)
|
|
*pkt_processed = processed;
|
|
}
|
|
|
|
static void vmci_transport_notify_pkt_process_request(struct sock *sk)
|
|
{
|
|
struct vsock_sock *vsk = vsock_sk(sk);
|
|
|
|
PKT_FIELD(vsk, write_notify_window) = vmci_trans(vsk)->consume_size;
|
|
if (vmci_trans(vsk)->consume_size <
|
|
PKT_FIELD(vsk, write_notify_min_window))
|
|
PKT_FIELD(vsk, write_notify_min_window) =
|
|
vmci_trans(vsk)->consume_size;
|
|
}
|
|
|
|
static void vmci_transport_notify_pkt_process_negotiate(struct sock *sk)
|
|
{
|
|
struct vsock_sock *vsk = vsock_sk(sk);
|
|
|
|
PKT_FIELD(vsk, write_notify_window) = vmci_trans(vsk)->consume_size;
|
|
if (vmci_trans(vsk)->consume_size <
|
|
PKT_FIELD(vsk, write_notify_min_window))
|
|
PKT_FIELD(vsk, write_notify_min_window) =
|
|
vmci_trans(vsk)->consume_size;
|
|
}
|
|
|
|
static int
|
|
vmci_transport_notify_pkt_recv_pre_dequeue(
|
|
struct sock *sk,
|
|
size_t target,
|
|
struct vmci_transport_recv_notify_data *data)
|
|
{
|
|
return 0; /* NOP for QState. */
|
|
}
|
|
|
|
static int
|
|
vmci_transport_notify_pkt_send_pre_block(
|
|
struct sock *sk,
|
|
struct vmci_transport_send_notify_data *data)
|
|
{
|
|
return 0; /* NOP for QState. */
|
|
}
|
|
|
|
static int
|
|
vmci_transport_notify_pkt_send_pre_enqueue(
|
|
struct sock *sk,
|
|
struct vmci_transport_send_notify_data *data)
|
|
{
|
|
return 0; /* NOP for QState. */
|
|
}
|
|
|
|
/* Socket always on control packet based operations. */
|
|
struct vmci_transport_notify_ops vmci_transport_notify_pkt_q_state_ops = {
|
|
vmci_transport_notify_pkt_socket_init,
|
|
vmci_transport_notify_pkt_socket_destruct,
|
|
vmci_transport_notify_pkt_poll_in,
|
|
vmci_transport_notify_pkt_poll_out,
|
|
vmci_transport_notify_pkt_handle_pkt,
|
|
vmci_transport_notify_pkt_recv_init,
|
|
vmci_transport_notify_pkt_recv_pre_block,
|
|
vmci_transport_notify_pkt_recv_pre_dequeue,
|
|
vmci_transport_notify_pkt_recv_post_dequeue,
|
|
vmci_transport_notify_pkt_send_init,
|
|
vmci_transport_notify_pkt_send_pre_block,
|
|
vmci_transport_notify_pkt_send_pre_enqueue,
|
|
vmci_transport_notify_pkt_send_post_enqueue,
|
|
vmci_transport_notify_pkt_process_request,
|
|
vmci_transport_notify_pkt_process_negotiate,
|
|
};
|