diff options
Diffstat (limited to 'net/vmw_vsock/vmci_transport_notify.c')
| -rw-r--r-- | net/vmw_vsock/vmci_transport_notify.c | 680 |
1 files changed, 680 insertions, 0 deletions
diff --git a/net/vmw_vsock/vmci_transport_notify.c b/net/vmw_vsock/vmci_transport_notify.c new file mode 100644 index 000000000000..9a730744e7bc --- /dev/null +++ b/net/vmw_vsock/vmci_transport_notify.c @@ -0,0 +1,680 @@ +/* + * 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.field_name) + +static bool vmci_transport_notify_waiting_write(struct vsock_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 = vmci_trans(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(vmci_trans(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 +} + +static bool vmci_transport_notify_waiting_read(struct vsock_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(vmci_trans(vsk)->qpair) > 0; +#else + return true; +#endif +} + +static void +vmci_transport_handle_waiting_read(struct sock *sk, + struct vmci_transport_packet *pkt, + bool bottom_half, + struct sockaddr_vm *dst, + struct sockaddr_vm *src) +{ +#if defined(VSOCK_OPTIMIZATION_WAITING_NOTIFY) + struct vsock_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 (vmci_transport_notify_waiting_read(vsk)) { + bool sent; + + if (bottom_half) + sent = vmci_transport_send_wrote_bh(dst, src) > 0; + else + sent = vmci_transport_send_wrote(sk) > 0; + + if (sent) + PKT_FIELD(vsk, peer_waiting_read) = false; + } +#endif +} + +static void +vmci_transport_handle_waiting_write(struct sock *sk, + struct vmci_transport_packet *pkt, + bool bottom_half, + struct sockaddr_vm *dst, + struct sockaddr_vm *src) +{ +#if defined(VSOCK_OPTIMIZATION_WAITING_NOTIFY) + struct vsock_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 (vmci_transport_notify_waiting_write(vsk)) { + bool sent; + + if (bottom_half) + sent = vmci_transport_send_read_bh(dst, src) > 0; + else + sent = vmci_transport_send_read(sk) > 0; + + if (sent) + PKT_FIELD(vsk, peer_waiting_write) = false; + } +#endif +} + +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) +{ +#if defined(VSOCK_OPTIMIZATION_WAITING_NOTIFY) + struct vsock_sock *vsk; + + vsk = vsock_sk(sk); + PKT_FIELD(vsk, sent_waiting_write) = false; +#endif + + sk->sk_write_space(sk); +} + +static bool send_waiting_read(struct sock *sk, u64 room_needed) +{ +#if defined(VSOCK_OPTIMIZATION_WAITING_NOTIFY) + struct vsock_sock *vsk; + struct vmci_transport_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) < + 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); + + vmci_qpair_get_consume_indexes(vmci_trans(vsk)->qpair, &tail, &head); + room_left = vmci_trans(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 = vmci_transport_send_waiting_read(sk, &waiting_info) > 0; + if (ret) + PKT_FIELD(vsk, sent_waiting_read) = true; + + return ret; +#else + return true; +#endif +} + +static bool send_waiting_write(struct sock *sk, u64 room_needed) +{ +#if defined(VSOCK_OPTIMIZATION_WAITING_NOTIFY) + struct vsock_sock *vsk; + struct vmci_transport_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(vmci_trans(vsk)->qpair, &tail, &head); + room_left = vmci_trans(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 = vmci_transport_send_waiting_write(sk, &waiting_info) > 0; + if (ret) + PKT_FIELD(vsk, sent_waiting_write) = true; + + return ret; +#else + return true; +#endif +} + +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) + pr_err("%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; +} + +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) +{ +#if defined(VSOCK_OPTIMIZATION_WAITING_NOTIFY) + struct vsock_sock *vsk = vsock_sk(sk); + PKT_FIELD(vsk, sent_waiting_read) = false; +#endif + sk->sk_data_ready(sk, 0); +} + +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_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))); +} + +static void vmci_transport_notify_pkt_socket_destruct(struct vsock_sock *vsk) +{ +} + +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) { + if (!send_waiting_read(sk, 1)) + return -1; + + } + *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. + * 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 (!send_waiting_write(sk, 1)) + return -1; + + *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); + +#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) { + 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; +} + +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; + + /* Notify our peer that we are waiting for data to read. */ + if (!send_waiting_read(sk, target)) { + err = -EHOSTUNREACH; + return err; + } +#ifdef VSOCK_OPTIMIZATION_FLOW_CONTROL + if (data->notify_on_block) { + err = vmci_transport_send_read_notification(sk); + if (err < 0) + return err; + + data->notify_on_block = false; + } +#endif + + return err; +} + +static int +vmci_transport_notify_pkt_recv_pre_dequeue( + struct sock *sk, + size_t target, + struct vmci_transport_recv_notify_data *data) +{ + struct vsock_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(vmci_trans(vsk)->qpair, + &data->produce_tail, + &data->consume_head); +#endif + + return 0; +} + +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; + + 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 >= + vmci_trans(vsk)->consume_size - data->consume_head) + PKT_FIELD(vsk, consume_q_generation)++; +#endif + + err = vmci_transport_send_read_notification(sk); + if (err < 0) + return err; + + } + return err; +} + +static int +vmci_transport_notify_pkt_send_init( + struct sock *sk, + struct vmci_transport_send_notify_data *data) +{ +#ifdef VSOCK_OPTIMIZATION_WAITING_NOTIFY + data->consume_head = 0; + data->produce_tail = 0; +#endif + + return 0; +} + +static int +vmci_transport_notify_pkt_send_pre_block( + struct sock *sk, + struct vmci_transport_send_notify_data *data) +{ + /* Notify our peer that we are waiting for room to write. */ + if (!send_waiting_write(sk, 1)) + return -EHOSTUNREACH; + + return 0; +} + +static int +vmci_transport_notify_pkt_send_pre_enqueue( + struct sock *sk, + struct vmci_transport_send_notify_data *data) +{ + struct vsock_sock *vsk = vsock_sk(sk); + +#if defined(VSOCK_OPTIMIZATION_WAITING_NOTIFY) + vmci_qpair_get_produce_indexes(vmci_trans(vsk)->qpair, + &data->produce_tail, + &data->consume_head); +#endif + + 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; + 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 >= vmci_trans(vsk)->produce_size - data->produce_tail) + PKT_FIELD(vsk, produce_q_generation)++; + +#endif + + if (vmci_transport_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 < 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) { + pr_err("%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; +} + +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; + case VMCI_TRANSPORT_PACKET_TYPE_WAITING_WRITE: + vmci_transport_handle_waiting_write(sk, pkt, bottom_half, + dst, src); + processed = true; + break; + + case VMCI_TRANSPORT_PACKET_TYPE_WAITING_READ: + vmci_transport_handle_waiting_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; +} + +/* Socket control packet based operations. */ +struct vmci_transport_notify_ops vmci_transport_notify_pkt_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, +}; |