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Message-ID: <20121105180108.21472.39071.stgit@promb-2n-dhcp175.eng.vmware.com>
Date: Mon, 05 Nov 2012 10:01:14 -0800
From: George Zhang <georgezhang@...are.com>
To: netdev@...r.kernel.org, linux-kernel@...r.kernel.org,
georgezhang@...are.com, virtualization@...ts.linux-foundation.org
Cc: pv-drivers@...are.com, vm-crosstalk@...are.com,
davem@...emloft.net, gregkh@...uxfoundation.org
Subject: [PATCH 3/6] VSOCK: notification implementation.
VSOCK control notifications for VMCI Stream Sockets protocol.
Signed-off-by: George Zhang <georgezhang@...are.com>
---
net/vmw_vsock/notify.c | 984 ++++++++++++++++++++++++++++++++++++++++++++++++
net/vmw_vsock/notify.h | 130 ++++++
2 files changed, 1114 insertions(+), 0 deletions(-)
create mode 100644 net/vmw_vsock/notify.c
create mode 100644 net/vmw_vsock/notify.h
diff --git a/net/vmw_vsock/notify.c b/net/vmw_vsock/notify.c
new file mode 100644
index 0000000..5c69c7c
--- /dev/null
+++ b/net/vmw_vsock/notify.c
@@ -0,0 +1,984 @@
+/*
+ * VMware vSockets Driver
+ *
+ * Copyright (C) 2009-2012 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.
+ */
+
+/*
+ * notify.c --
+ *
+ * Linux control notifications for the VMCI Stream Sockets protocol.
+ */
+
+#include <linux/types.h>
+
+#include <linux/socket.h>
+#include <linux/stddef.h> /* for NULL */
+#include <net/sock.h>
+
+#include "notify.h"
+#include "af_vsock.h"
+
+#define PKT_FIELD(vsk, field_name) \
+ (vsk)->notify.pkt.field_name
+
+#define VSOCK_MAX_DGRAM_RESENDS 10
+
+/*
+ *
+ * vsock_vmci_notify_waiting_write --
+ *
+ * Determines if the conditions have been met to notify a waiting writer.
+ *
+ * Results: true if a notification should be sent, false otherwise.
+ *
+ * Side effects: None.
+ */
+
+static bool vsock_vmci_notify_waiting_write(vsock_vmci_sock *vsk)
+{
+#if defined(VSOCK_OPTIMIZATION_WAITING_NOTIFY)
+ bool retval;
+ u64 notify_limit;
+
+ if (!PKT_FIELD(vsk, peer_waiting_write))
+ return false;
+
+#ifdef VSOCK_OPTIMIZATION_FLOW_CONTROL
+ /*
+ * 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 = vsk->consume_size - PKT_FIELD(vsk, write_notify_window);
+#else
+ notify_limit = 0;
+#endif
+
+ /*
+ * For now we ignore the wait information and just see if the free
+ * space exceeds the notify limit. Note that improving this function
+ * to be more intelligent will not require a protocol change and will
+ * retain compatibility between endpoints with mixed versions of this
+ * function.
+ *
+ * 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(vsk->qpair) > notify_limit;
+#ifdef VSOCK_OPTIMIZATION_FLOW_CONTROL
+ 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;
+ }
+#endif
+ return retval;
+#else
+ return true;
+#endif
+}
+
+/*
+ *
+ * vsock_vmci_notify_waiting_read --
+ *
+ * Determines if the conditions have been met to notify a waiting reader.
+ *
+ * Results: true if a notification should be sent, false otherwise.
+ *
+ * Side effects: None.
+ */
+
+static bool vsock_vmci_notify_waiting_read(vsock_vmci_sock *vsk)
+{
+#if defined(VSOCK_OPTIMIZATION_WAITING_NOTIFY)
+ if (!PKT_FIELD(vsk, peer_waiting_read))
+ return false;
+
+ /*
+ * For now we ignore the wait information and just see if there is any
+ * data for our peer to read. Note that improving this function to be
+ * more intelligent will not require a protocol change and will retain
+ * compatibility between endpoints with mixed versions of this
+ * function.
+ */
+ return vmci_qpair_produce_buf_ready(vsk->qpair) > 0;
+#else
+ return true;
+#endif
+}
+
+/*
+ *
+ * vsock_vmci_handle_waiting_read --
+ *
+ * Handles an incoming waiting read message.
+ *
+ * Results: None.
+ *
+ * Side effects: May send a notification to the peer, may update socket's wait
+ * info structure.
+ */
+
+static void
+vsock_vmci_handle_waiting_read(struct sock *sk,
+ vsock_packet *pkt,
+ bool bottom_half,
+ struct sockaddr_vm *dst, struct sockaddr_vm *src)
+{
+#if defined(VSOCK_OPTIMIZATION_WAITING_NOTIFY)
+ vsock_vmci_sock *vsk;
+
+ vsk = vsock_sk(sk);
+
+ PKT_FIELD(vsk, peer_waiting_read) = true;
+ memcpy(&PKT_FIELD(vsk, peer_waiting_read_info), &pkt->u.wait,
+ sizeof PKT_FIELD(vsk, peer_waiting_read_info));
+
+ if (vsock_vmci_notify_waiting_read(vsk)) {
+ bool sent;
+
+ if (bottom_half)
+ sent = VSOCK_SEND_WROTE_BH(dst, src) > 0;
+ else
+ sent = VSOCK_SEND_WROTE(sk) > 0;
+
+ if (sent)
+ PKT_FIELD(vsk, peer_waiting_read) = false;
+
+ }
+#endif
+}
+
+/*
+ *
+ * vsock_vmci_handle_waiting_write --
+ *
+ * Handles an incoming waiting write message.
+ *
+ * Results: None.
+ *
+ * Side effects: May send a notification to the peer, may update socket's wait
+ * info structure.
+ */
+
+static void
+vsock_vmci_handle_waiting_write(struct sock *sk,
+ vsock_packet *pkt,
+ bool bottom_half,
+ struct sockaddr_vm *dst,
+ struct sockaddr_vm *src)
+{
+#if defined(VSOCK_OPTIMIZATION_WAITING_NOTIFY)
+ vsock_vmci_sock *vsk;
+
+ vsk = vsock_sk(sk);
+
+ PKT_FIELD(vsk, peer_waiting_write) = true;
+ memcpy(&PKT_FIELD(vsk, peer_waiting_write_info), &pkt->u.wait,
+ sizeof PKT_FIELD(vsk, peer_waiting_write_info));
+
+ if (vsock_vmci_notify_waiting_write(vsk)) {
+ bool sent;
+
+ if (bottom_half)
+ sent = VSOCK_SEND_READ_BH(dst, src) > 0;
+ else
+ sent = VSOCK_SEND_READ(sk) > 0;
+
+ if (sent)
+ PKT_FIELD(vsk, peer_waiting_write) = false;
+
+ }
+#endif
+}
+
+/*
+ *
+ * vsock_vmci_handle_read --
+ *
+ * Handles an incoming read message.
+ *
+ * Results: None.
+ *
+ * Side effects: None.
+ */
+
+static void
+vsock_vmci_handle_read(struct sock *sk,
+ vsock_packet *pkt,
+ bool bottom_half,
+ struct sockaddr_vm *dst, struct sockaddr_vm *src)
+{
+#if defined(VSOCK_OPTIMIZATION_WAITING_NOTIFY)
+ vsock_vmci_sock *vsk;
+
+ vsk = vsock_sk(sk);
+ PKT_FIELD(vsk, sent_waiting_write) = false;
+#endif
+
+ sk->sk_write_space(sk);
+}
+
+/*
+ *
+ * vsock_vmci_send_waiting_read --
+ *
+ * Sends a waiting read notification to this socket's peer.
+ *
+ * Results: true if the datagram is sent successfully, false otherwise.
+ *
+ * Side effects: Our peer will notify us when there is data to read from our
+ * consume queue.
+ */
+
+static bool vsock_vmci_send_waiting_read(struct sock *sk, u64 room_needed)
+{
+#if defined(VSOCK_OPTIMIZATION_WAITING_NOTIFY)
+ vsock_vmci_sock *vsk;
+ vsock_waiting_info waiting_info;
+ u64 tail;
+ u64 head;
+ u64 room_left;
+ bool ret;
+
+ vsk = vsock_sk(sk);
+
+ if (PKT_FIELD(vsk, sent_waiting_read))
+ return true;
+
+ if (PKT_FIELD(vsk, write_notify_window) < vsk->consume_size)
+ PKT_FIELD(vsk, write_notify_window) =
+ min(PKT_FIELD(vsk, write_notify_window) + PAGE_SIZE,
+ vsk->consume_size);
+
+ vmci_qpair_get_consume_indexes(vsk->qpair, &tail, &head);
+ room_left = vsk->consume_size - head;
+ if (room_needed >= room_left) {
+ waiting_info.offset = room_needed - room_left;
+ waiting_info.generation =
+ PKT_FIELD(vsk, consume_q_generation) + 1;
+ } else {
+ waiting_info.offset = head + room_needed;
+ waiting_info.generation = PKT_FIELD(vsk, consume_q_generation);
+ }
+
+ ret = VSOCK_SEND_WAITING_READ(sk, &waiting_info) > 0;
+ if (ret)
+ PKT_FIELD(vsk, sent_waiting_read) = true;
+
+ return ret;
+#else
+ return true;
+#endif
+}
+
+/*
+ *
+ * vsock_vmci_send_waiting_write --
+ *
+ * Sends a waiting write notification to this socket's peer.
+ *
+ * Results: true if the datagram is sent successfully or does not need to be
+ * sent. false otherwise.
+ *
+ * Side effects: Our peer will notify us when there is room to write in to our
+ * produce queue.
+ */
+
+static bool vsock_vmci_send_waiting_write(struct sock *sk, u64 room_needed)
+{
+#if defined(VSOCK_OPTIMIZATION_WAITING_NOTIFY)
+ vsock_vmci_sock *vsk;
+ vsock_waiting_info waiting_info;
+ u64 tail;
+ u64 head;
+ u64 room_left;
+ bool ret;
+
+ vsk = vsock_sk(sk);
+
+ if (PKT_FIELD(vsk, sent_waiting_write))
+ return true;
+
+ vmci_qpair_get_produce_indexes(vsk->qpair, &tail, &head);
+ room_left = vsk->produce_size - tail;
+ if (room_needed + 1 >= room_left) {
+ /* Wraps around to current generation. */
+ waiting_info.offset = room_needed + 1 - room_left;
+ waiting_info.generation = PKT_FIELD(vsk, produce_q_generation);
+ } else {
+ waiting_info.offset = tail + room_needed + 1;
+ waiting_info.generation =
+ PKT_FIELD(vsk, produce_q_generation) - 1;
+ }
+
+ ret = VSOCK_SEND_WAITING_WRITE(sk, &waiting_info) > 0;
+ if (ret)
+ PKT_FIELD(vsk, sent_waiting_write) = true;
+
+ return ret;
+#else
+ return true;
+#endif
+}
+
+/*
+ *
+ * vsock_vmci_send_read_notification --
+ *
+ * Sends a read notification to this socket's peer.
+ *
+ * Results: >= 0 if the datagram is sent successfully, negative error value
+ * otherwise.
+ *
+ * Side effects: None.
+ */
+
+static int vsock_vmci_send_read_notification(struct sock *sk)
+{
+ vsock_vmci_sock *vsk;
+ bool sent_read;
+ unsigned int retries;
+ int err;
+
+ vsk = vsock_sk(sk);
+ sent_read = false;
+ retries = 0;
+ err = 0;
+
+ if (vsock_vmci_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 < VSOCK_MAX_DGRAM_RESENDS) {
+ err = VSOCK_SEND_READ(sk);
+ if (err >= 0)
+ sent_read = true;
+
+ retries++;
+ }
+
+ if (retries >= VSOCK_MAX_DGRAM_RESENDS)
+ printk
+ ("%p unable to send read notify to peer.\n",
+ sk);
+ else
+#if defined(VSOCK_OPTIMIZATION_WAITING_NOTIFY)
+ PKT_FIELD(vsk, peer_waiting_write) = false;
+#endif
+
+ }
+ return err;
+}
+
+/*
+ *
+ * vsock_vmci_handle_wrote --
+ *
+ * Handles an incoming wrote message.
+ *
+ * Results: None.
+ *
+ * Side effects: None.
+ */
+
+static void
+vsock_vmci_handle_wrote(struct sock *sk,
+ vsock_packet *pkt,
+ bool bottom_half,
+ struct sockaddr_vm *dst, struct sockaddr_vm *src)
+{
+#if defined(VSOCK_OPTIMIZATION_WAITING_NOTIFY)
+ vsock_vmci_sock *vsk;
+
+ vsk = vsock_sk(sk);
+ PKT_FIELD(vsk, sent_waiting_read) = false;
+#endif
+
+ sk->sk_data_ready(sk, 0);
+}
+
+/*
+ *
+ * vsock_vmci_notify_pkt_socket_init --
+ *
+ * Function that is called after a socket is created and before any notify ops
+ * are used.
+ *
+ * Results: None.
+ *
+ * Side effects: None.
+ */
+
+static void vsock_vmci_notify_pkt_socket_init(struct sock *sk)
+{
+ vsock_vmci_sock *vsk;
+ 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_read) = false;
+ PKT_FIELD(vsk, peer_waiting_write) = false;
+ PKT_FIELD(vsk, peer_waiting_write_detected) = false;
+ PKT_FIELD(vsk, sent_waiting_read) = false;
+ PKT_FIELD(vsk, sent_waiting_write) = false;
+ PKT_FIELD(vsk, produce_q_generation) = 0;
+ PKT_FIELD(vsk, consume_q_generation) = 0;
+
+ memset(&PKT_FIELD(vsk, peer_waiting_read_info), 0,
+ sizeof PKT_FIELD(vsk, peer_waiting_read_info));
+ memset(&PKT_FIELD(vsk, peer_waiting_write_info), 0,
+ sizeof PKT_FIELD(vsk, peer_waiting_write_info));
+}
+
+/*
+ *
+ * vsock_vmci_notify_pkt_socket_destruct --
+ *
+ * Function that is called when the socket is being released.
+ *
+ * Results: None.
+ *
+ * Side effects: None.
+ */
+
+static void vsock_vmci_notify_pkt_socket_destruct(struct sock *sk)
+{
+ return;
+}
+
+/*
+ *
+ * vsock_vmci_notify_pkt_poll_in --
+ *
+ * Called by the poll function to figure out if there is data to read and to
+ * setup future notifications if needed. Only called on sockets that aren't
+ * shutdown for recv.
+ *
+ * Results: 0 on success. Negative error on failure.
+ *
+ * Side effects: None.
+ */
+
+static int
+vsock_vmci_notify_pkt_poll_in(struct sock *sk,
+ size_t target, bool *data_ready_now)
+{
+ vsock_vmci_sock *vsk = vsock_sk(sk);
+
+ if (vsock_vmci_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) {
+ if (!vsock_vmci_send_waiting_read(sk, 1))
+ return -1;
+
+ }
+ *data_ready_now = false;
+ }
+
+ return 0;
+}
+
+/*
+ *
+ * vsock_vmci_notify_pkt_poll_out
+ *
+ * Called by the poll function to figure out if there is space to write and to
+ * setup future notifications if needed. Only called on a connected socket that
+ * isn't shutdown for send.
+ *
+ * Results: 0 on success. Negative error on failure.
+ *
+ * Side effects: None.
+ */
+
+static int
+vsock_vmci_notify_pkt_poll_out(struct sock *sk,
+ size_t target, bool *space_avail_now)
+{
+ s64 produce_q_free_space;
+ vsock_vmci_sock *vsk = vsock_sk(sk);
+
+ produce_q_free_space = vsock_vmci_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.
+ * Notify the peer that we are waiting if the queue is full. We
+ * only send a waiting write if the queue is full because
+ * otherwise we end up in an infinite WAITING_WRITE, READ,
+ * WAITING_WRITE, READ, etc. loop. Treat failing to send the
+ * notification as a socket error, passing that back through
+ * the mask.
+ */
+ if (!vsock_vmci_send_waiting_write(sk, 1))
+ return -1;
+
+ *space_avail_now = false;
+ }
+
+ return 0;
+}
+
+/*
+ *
+ * vsock_vmci_notify_pkt_recv_init --
+ *
+ * Called at the start of a stream recv call with the socket lock held.
+ *
+ * Results: 0 on success. Negative error on failure.
+ *
+ * Side effects: None.
+ */
+
+static int
+vsock_vmci_notify_pkt_recv_init(struct sock *sk,
+ size_t target,
+ vsock_vmci_recv_notify_data *data)
+{
+ vsock_vmci_sock *vsk;
+
+ vsk = vsock_sk(sk);
+
+#ifdef VSOCK_OPTIMIZATION_WAITING_NOTIFY
+ data->consume_head = 0;
+ data->produce_tail = 0;
+#ifdef VSOCK_OPTIMIZATION_FLOW_CONTROL
+ data->notify_on_block = false;
+
+ if (PKT_FIELD(vsk, write_notify_min_window) < target + 1) {
+ ASSERT(target < vsk->consume_size);
+ 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;
+ }
+ }
+#endif
+#endif
+
+ return 0;
+}
+
+/*
+ *
+ * vsock_vmci_notify_pkt_recv_pre_block --
+ *
+ * Called right before a socket is about to block with the socket lock held.
+ * The socket lock may have been released between the entry function and the
+ * preblock call.
+ *
+ * Note: This function may be called multiple times before the post block
+ * function is called.
+ *
+ * Results: 0 on success. Negative error on failure.
+ *
+ * Side effects: None.
+ */
+
+static int
+vsock_vmci_notify_pkt_recv_pre_block(struct sock *sk,
+ size_t target,
+ vsock_vmci_recv_notify_data *data)
+{
+ int err = 0;
+
+ /* Notify our peer that we are waiting for data to read. */
+ if (!vsock_vmci_send_waiting_read(sk, target)) {
+ err = -EHOSTUNREACH;
+ return err;
+ }
+#ifdef VSOCK_OPTIMIZATION_FLOW_CONTROL
+ if (data->notify_on_block) {
+ err = vsock_vmci_send_read_notification(sk);
+ if (err < 0)
+ return err;
+
+ data->notify_on_block = false;
+ }
+#endif
+
+ return err;
+}
+
+/*
+ *
+ * vsock_vmci_notify_pkt_recv_pre_dequeue --
+ *
+ * Called right before we dequeue / peek data from a socket.
+ *
+ * Results: 0 on success. Negative error on failure.
+ *
+ * Side effects: None.
+ */
+
+static int
+vsock_vmci_notify_pkt_recv_pre_dequeue(struct sock *sk,
+ size_t target,
+ vsock_vmci_recv_notify_data *data)
+{
+ vsock_vmci_sock *vsk = vsock_sk(sk);
+
+ /*
+ * Now consume up to len bytes from the queue. Note that since we have
+ * the socket locked we should copy at least ready bytes.
+ */
+#if defined(VSOCK_OPTIMIZATION_WAITING_NOTIFY)
+ vmci_qpair_get_consume_indexes(vsk->qpair,
+ &data->produce_tail,
+ &data->consume_head);
+#endif
+
+ return 0;
+}
+
+/*
+ *
+ * vsock_vmci_notify_pkt_recv_post_dequeue --
+ *
+ * Called right after we dequeue / peek data from a socket.
+ *
+ * Results: 0 on success. Negative error on failure.
+ *
+ * Side effects: None.
+ */
+
+static int
+vsock_vmci_notify_pkt_recv_post_dequeue(struct sock *sk,
+ size_t target,
+ ssize_t copied,
+ bool data_read,
+ vsock_vmci_recv_notify_data *data)
+{
+ vsock_vmci_sock *vsk;
+ int err;
+
+ vsk = vsock_sk(sk);
+ err = 0;
+
+ if (data_read) {
+#if defined(VSOCK_OPTIMIZATION_WAITING_NOTIFY)
+ /*
+ * Detect a wrap-around to maintain queue generation. Note
+ * that this is safe since we hold the socket lock across the
+ * two queue pair operations.
+ */
+ if (copied >= vsk->consume_size - data->consume_head)
+ PKT_FIELD(vsk, consume_q_generation)++;
+
+#endif
+
+ err = vsock_vmci_send_read_notification(sk);
+ if (err < 0)
+ return err;
+
+ }
+ return err;
+}
+
+/*
+ *
+ * vsock_vmci_notify_pkt_send_init --
+ *
+ * Called at the start of a stream send call with the socket lock held.
+ *
+ * Results: 0 on success. A negative error code on failure.
+ *
+ * Side effects:
+ */
+
+static int
+vsock_vmci_notify_pkt_send_init(struct sock *sk,
+ vsock_vmci_send_notify_data *data)
+{
+#ifdef VSOCK_OPTIMIZATION_WAITING_NOTIFY
+ data->consume_head = 0;
+ data->produce_tail = 0;
+#endif
+
+ return 0;
+}
+
+/*
+ *
+ * vsock_vmci_notify_pkt_send_pre_block --
+ *
+ * Called right before a socket is about to block with the socket lock held.
+ * The socket lock may have been released between the entry function and the
+ * preblock call.
+ *
+ * Note: This function may be called multiple times before the post block
+ * function is called.
+ *
+ * Results. 0 on success. A negative error code on failure.
+ *
+ * Side effects: None.
+ */
+
+static int
+vsock_vmci_notify_pkt_send_pre_block(struct sock *sk,
+ vsock_vmci_send_notify_data *data)
+{
+ /* Notify our peer that we are waiting for room to write. */
+ if (!vsock_vmci_send_waiting_write(sk, 1))
+ return -EHOSTUNREACH;
+
+ return 0;
+}
+
+/*
+ *
+ * vsock_vmci_notifySendPreEnqueue --
+ *
+ * Called right before we Enqueue to a socket.
+ *
+ * Results: 0 on success. Negative error on failure.
+ *
+ * Side effects: None.
+ */
+
+static int
+vsock_vmci_notify_pkt_send_pre_enqueue(struct sock *sk,
+ vsock_vmci_send_notify_data *data)
+{
+ vsock_vmci_sock *vsk = vsock_sk(sk);
+
+#if defined(VSOCK_OPTIMIZATION_WAITING_NOTIFY)
+ vmci_qpair_get_produce_indexes(vsk->qpair,
+ &data->produce_tail,
+ &data->consume_head);
+#endif
+
+ return 0;
+}
+
+/*
+ *
+ * vsock_vmci_notifySendPostEnqueue --
+ *
+ * Called right after we enqueue data to a socket.
+ *
+ * Results: 0 on success. Negative error on failure.
+ *
+ * Side effects: None.
+ */
+
+static int
+vsock_vmci_notify_pkt_send_post_enqueue(struct sock *sk,
+ ssize_t written,
+ vsock_vmci_send_notify_data *data)
+{
+ int err = 0;
+ vsock_vmci_sock *vsk;
+ bool sent_wrote = false;
+ int retries = 0;
+
+ vsk = vsock_sk(sk);
+
+#if defined(VSOCK_OPTIMIZATION_WAITING_NOTIFY)
+ /*
+ * Detect a wrap-around to maintain queue generation. Note that this
+ * is safe since we hold the socket lock across the two queue pair
+ * operations.
+ */
+ if (written >= vsk->produce_size - data->produce_tail)
+ PKT_FIELD(vsk, produce_q_generation)++;
+
+#endif
+
+ if (vsock_vmci_notify_waiting_read(vsk)) {
+ /*
+ * Notify the peer that we have written, retrying the send on
+ * failure up to our maximum value. See the XXX comment for the
+ * corresponding piece of code in StreamRecvmsg() for potential
+ * improvements.
+ */
+ while (!(vsk->peer_shutdown & RCV_SHUTDOWN) &&
+ !sent_wrote && retries < VSOCK_MAX_DGRAM_RESENDS) {
+ err = VSOCK_SEND_WROTE(sk);
+ if (err >= 0)
+ sent_wrote = true;
+
+ retries++;
+ }
+
+ if (retries >= VSOCK_MAX_DGRAM_RESENDS) {
+ printk
+ (" %p unable to send wrote notify to peer.\n",
+ sk);
+ return err;
+ } else {
+#if defined(VSOCK_OPTIMIZATION_WAITING_NOTIFY)
+ PKT_FIELD(vsk, peer_waiting_read) = false;
+#endif
+ }
+ }
+ return err;
+}
+
+/*
+ *
+ * vsock_vmci_notify_pkt_handle_pkt
+ *
+ * Called when a notify packet is recieved for a socket in the connected state.
+ * Note this might be called from a bottom half.
+ *
+ * Results: None.
+ *
+ * Side effects: None.
+ */
+
+static void
+vsock_vmci_notify_pkt_handle_pkt(struct sock *sk,
+ vsock_packet *pkt,
+ bool bottom_half,
+ struct sockaddr_vm *dst,
+ struct sockaddr_vm *src, bool *pkt_processed)
+{
+ bool processed = false;
+
+ switch (pkt->type) {
+ case VSOCK_PACKET_TYPE_WROTE:
+ vsock_vmci_handle_wrote(sk, pkt, bottom_half, dst, src);
+ processed = true;
+ break;
+ case VSOCK_PACKET_TYPE_READ:
+ vsock_vmci_handle_read(sk, pkt, bottom_half, dst, src);
+ processed = true;
+ break;
+ case VSOCK_PACKET_TYPE_WAITING_WRITE:
+ vsock_vmci_handle_waiting_write(sk, pkt, bottom_half, dst, src);
+ processed = true;
+ break;
+
+ case VSOCK_PACKET_TYPE_WAITING_READ:
+ vsock_vmci_handle_waiting_read(sk, pkt, bottom_half, dst, src);
+ processed = true;
+ break;
+ }
+
+ if (pkt_processed)
+ *pkt_processed = processed;
+
+}
+
+/*
+ *
+ * vsock_vmci_notify_pkt_process_request
+ *
+ * Called near the end of process request.
+ *
+ * Results: None.
+ *
+ * Side effects: None.
+ */
+
+static void vsock_vmci_notify_pkt_process_request(struct sock *sk)
+{
+ vsock_vmci_sock *vsk = vsock_sk(sk);
+
+ PKT_FIELD(vsk, write_notify_window) = vsk->consume_size;
+ if (vsk->consume_size < PKT_FIELD(vsk, write_notify_min_window))
+ PKT_FIELD(vsk, write_notify_min_window) = vsk->consume_size;
+
+}
+
+/*
+ *
+ * vsock_vmci_notify_pkt_process_negotiate
+ *
+ * Called near the end of process negotiate.
+ *
+ * Results: None.
+ *
+ * Side effects: None.
+ */
+
+static void vsock_vmci_notify_pkt_process_negotiate(struct sock *sk)
+{
+ vsock_vmci_sock *vsk = vsock_sk(sk);
+
+ PKT_FIELD(vsk, write_notify_window) = vsk->consume_size;
+ if (vsk->consume_size < PKT_FIELD(vsk, write_notify_min_window))
+ PKT_FIELD(vsk, write_notify_min_window) = vsk->consume_size;
+
+}
+
+/* Socket control packet based operations. */
+vsock_vmci_notify_ops vsock_vmci_notify_pkt_ops = {
+ vsock_vmci_notify_pkt_socket_init,
+ vsock_vmci_notify_pkt_socket_destruct,
+ vsock_vmci_notify_pkt_poll_in,
+ vsock_vmci_notify_pkt_poll_out,
+ vsock_vmci_notify_pkt_handle_pkt,
+ vsock_vmci_notify_pkt_recv_init,
+ vsock_vmci_notify_pkt_recv_pre_block,
+ vsock_vmci_notify_pkt_recv_pre_dequeue,
+ vsock_vmci_notify_pkt_recv_post_dequeue,
+ vsock_vmci_notify_pkt_send_init,
+ vsock_vmci_notify_pkt_send_pre_block,
+ vsock_vmci_notify_pkt_send_pre_enqueue,
+ vsock_vmci_notify_pkt_send_post_enqueue,
+ vsock_vmci_notify_pkt_process_request,
+ vsock_vmci_notify_pkt_process_negotiate,
+};
diff --git a/net/vmw_vsock/notify.h b/net/vmw_vsock/notify.h
new file mode 100644
index 0000000..fe39442
--- /dev/null
+++ b/net/vmw_vsock/notify.h
@@ -0,0 +1,130 @@
+/*
+ * VMware vSockets Driver
+ *
+ * Copyright (C) 2009-2012 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.
+ */
+
+/*
+ * notify.h --
+ *
+ * Notify functions for Linux VSocket module.
+ */
+
+#ifndef __NOTIFY_H__
+#define __NOTIFY_H__
+
+#include <linux/types.h>
+
+#include "vsock_common.h"
+#include "vsock_packet.h"
+
+/* Comment this out to compare with old protocol. */
+#define VSOCK_OPTIMIZATION_WAITING_NOTIFY 1
+#if defined(VSOCK_OPTIMIZATION_WAITING_NOTIFY)
+/* Comment this out to remove flow control for "new" protocol */
+#define VSOCK_OPTIMIZATION_FLOW_CONTROL 1
+#endif
+
+#define VSOCK_MAX_DGRAM_RESENDS 10
+
+#define NOTIFYCALLRET(vsk, rv, mod_fn, args...) \
+ do { \
+ if (vsk->notify_ops && \
+ vsk->notify_ops->mod_fn != NULL) \
+ rv = (vsk->notify_ops->mod_fn)(args); \
+ else \
+ rv = 0; \
+ \
+ } while (0)
+
+#define NOTIFYCALL(vsk, mod_fn, args...) \
+ do { \
+ if (vsk->notify_ops && \
+ vsk->notify_ops->mod_fn != NULL) \
+ (vsk->notify_ops->mod_fn)(args); \
+ \
+ } while (0)
+
+typedef struct vsock_vmci_notify_pkt {
+ u64 write_notify_window;
+ u64 write_notify_min_window;
+ bool peer_waiting_read;
+ bool peer_waiting_write;
+ bool peer_waiting_write_detected;
+ bool sent_waiting_read;
+ bool sent_waiting_write;
+ vsock_waiting_info peer_waiting_read_info;
+ vsock_waiting_info peer_waiting_write_info;
+ u64 produce_q_generation;
+ u64 consume_q_generation;
+} vsock_vmci_notify_pkt;
+
+typedef struct vsock_vmci_notify_pkt_q_state {
+ u64 write_notify_window;
+ u64 write_notify_min_window;
+ bool peer_waiting_write;
+ bool peer_waiting_write_detected;
+} vsock_vmci_notify_pkt_q_state;
+
+typedef union vsock_vmci_notify {
+ vsock_vmci_notify_pkt pkt;
+ vsock_vmci_notify_pkt_q_state pkt_q_state;
+} vsock_vmci_notify;
+
+typedef struct vsock_vmci_recv_notify_data {
+ u64 consume_head;
+ u64 produce_tail;
+ bool notify_on_block;
+} vsock_vmci_recv_notify_data;
+
+typedef struct vsock_vmci_send_notify_data {
+ u64 consume_head;
+ u64 produce_tail;
+} vsock_vmci_send_notify_data;
+
+/* Socket notification callbacks. */
+typedef struct vsock_vmci_notify_ops {
+ void (*socket_init) (struct sock *sk);
+ void (*socket_destruct) (struct sock *sk);
+ int (*poll_in) (struct sock *sk, size_t target,
+ bool *data_ready_now);
+ int (*poll_out) (struct sock *sk, size_t target,
+ bool *space_avail_now);
+ void (*handle_notify_pkt) (struct sock *sk, vsock_packet *pkt,
+ bool bottom_half, struct sockaddr_vm *dst,
+ struct sockaddr_vm *src,
+ bool *pkt_processed);
+ int (*recv_init) (struct sock *sk, size_t target,
+ vsock_vmci_recv_notify_data *data);
+ int (*recv_pre_block) (struct sock *sk, size_t target,
+ vsock_vmci_recv_notify_data *data);
+ int (*recv_pre_dequeue) (struct sock *sk, size_t target,
+ vsock_vmci_recv_notify_data *data);
+ int (*recv_post_dequeue) (struct sock *sk, size_t target,
+ ssize_t copied, bool data_read,
+ vsock_vmci_recv_notify_data *data);
+ int (*send_init) (struct sock *sk,
+ vsock_vmci_send_notify_data *data);
+ int (*send_pre_block) (struct sock *sk,
+ vsock_vmci_send_notify_data *data);
+ int (*send_pre_enqueue) (struct sock *sk,
+ vsock_vmci_send_notify_data *data);
+ int (*send_post_enqueue) (struct sock *sk, ssize_t written,
+ vsock_vmci_send_notify_data *data);
+ void (*process_request) (struct sock *sk);
+ void (*process_negotiate) (struct sock *sk);
+} vsock_vmci_notify_ops;
+
+extern vsock_vmci_notify_ops vsock_vmci_notify_pkt_ops;
+extern vsock_vmci_notify_ops vsock_vmci_notify_pkt_q_state_ops;
+
+#endif /* __NOTIFY_H__ */
--
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