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430 lines
11 KiB
430 lines
11 KiB
// SPDX-License-Identifier: GPL-2.0-only |
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/* |
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* VMware vSockets Driver |
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* |
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* Copyright (C) 2009-2013 VMware, Inc. All rights reserved. |
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*/ |
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#include <linux/types.h> |
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#include <linux/socket.h> |
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#include <linux/stddef.h> |
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#include <net/sock.h> |
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#include "vmci_transport_notify.h" |
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#define PKT_FIELD(vsk, field_name) \ |
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(vmci_trans(vsk)->notify.pkt_q_state.field_name) |
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static bool vmci_transport_notify_waiting_write(struct vsock_sock *vsk) |
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{ |
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bool retval; |
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u64 notify_limit; |
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if (!PKT_FIELD(vsk, peer_waiting_write)) |
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return false; |
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|
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/* When the sender blocks, we take that as a sign that the sender is |
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* faster than the receiver. To reduce the transmit rate of the sender, |
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* we delay the sending of the read notification by decreasing the |
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* write_notify_window. The notification is delayed until the number of |
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* bytes used in the queue drops below the write_notify_window. |
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*/ |
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if (!PKT_FIELD(vsk, peer_waiting_write_detected)) { |
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PKT_FIELD(vsk, peer_waiting_write_detected) = true; |
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if (PKT_FIELD(vsk, write_notify_window) < PAGE_SIZE) { |
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PKT_FIELD(vsk, write_notify_window) = |
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PKT_FIELD(vsk, write_notify_min_window); |
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} else { |
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PKT_FIELD(vsk, write_notify_window) -= PAGE_SIZE; |
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if (PKT_FIELD(vsk, write_notify_window) < |
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PKT_FIELD(vsk, write_notify_min_window)) |
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PKT_FIELD(vsk, write_notify_window) = |
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PKT_FIELD(vsk, write_notify_min_window); |
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} |
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} |
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notify_limit = vmci_trans(vsk)->consume_size - |
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PKT_FIELD(vsk, write_notify_window); |
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/* The notify_limit is used to delay notifications in the case where |
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* flow control is enabled. Below the test is expressed in terms of |
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* free space in the queue: if free_space > ConsumeSize - |
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* write_notify_window then notify An alternate way of expressing this |
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* is to rewrite the expression to use the data ready in the receive |
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* queue: if write_notify_window > bufferReady then notify as |
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* free_space == ConsumeSize - bufferReady. |
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*/ |
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retval = vmci_qpair_consume_free_space(vmci_trans(vsk)->qpair) > |
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notify_limit; |
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if (retval) { |
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/* Once we notify the peer, we reset the detected flag so the |
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* next wait will again cause a decrease in the window size. |
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*/ |
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PKT_FIELD(vsk, peer_waiting_write_detected) = false; |
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} |
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return retval; |
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} |
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static void |
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vmci_transport_handle_read(struct sock *sk, |
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struct vmci_transport_packet *pkt, |
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bool bottom_half, |
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struct sockaddr_vm *dst, struct sockaddr_vm *src) |
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{ |
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sk->sk_write_space(sk); |
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} |
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static void |
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vmci_transport_handle_wrote(struct sock *sk, |
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struct vmci_transport_packet *pkt, |
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bool bottom_half, |
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struct sockaddr_vm *dst, struct sockaddr_vm *src) |
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{ |
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sk->sk_data_ready(sk); |
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} |
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static void vsock_block_update_write_window(struct sock *sk) |
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{ |
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struct vsock_sock *vsk = vsock_sk(sk); |
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if (PKT_FIELD(vsk, write_notify_window) < vmci_trans(vsk)->consume_size) |
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PKT_FIELD(vsk, write_notify_window) = |
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min(PKT_FIELD(vsk, write_notify_window) + PAGE_SIZE, |
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vmci_trans(vsk)->consume_size); |
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} |
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static int vmci_transport_send_read_notification(struct sock *sk) |
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{ |
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struct vsock_sock *vsk; |
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bool sent_read; |
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unsigned int retries; |
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int err; |
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vsk = vsock_sk(sk); |
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sent_read = false; |
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retries = 0; |
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err = 0; |
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if (vmci_transport_notify_waiting_write(vsk)) { |
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/* Notify the peer that we have read, retrying the send on |
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* failure up to our maximum value. XXX For now we just log |
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* the failure, but later we should schedule a work item to |
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* handle the resend until it succeeds. That would require |
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* keeping track of work items in the vsk and cleaning them up |
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* upon socket close. |
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*/ |
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while (!(vsk->peer_shutdown & RCV_SHUTDOWN) && |
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!sent_read && |
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retries < VMCI_TRANSPORT_MAX_DGRAM_RESENDS) { |
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err = vmci_transport_send_read(sk); |
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if (err >= 0) |
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sent_read = true; |
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retries++; |
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} |
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if (retries >= VMCI_TRANSPORT_MAX_DGRAM_RESENDS && !sent_read) |
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pr_err("%p unable to send read notification to peer\n", |
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sk); |
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else |
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PKT_FIELD(vsk, peer_waiting_write) = false; |
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} |
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return err; |
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} |
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static void vmci_transport_notify_pkt_socket_init(struct sock *sk) |
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{ |
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struct vsock_sock *vsk = vsock_sk(sk); |
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PKT_FIELD(vsk, write_notify_window) = PAGE_SIZE; |
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PKT_FIELD(vsk, write_notify_min_window) = PAGE_SIZE; |
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PKT_FIELD(vsk, peer_waiting_write) = false; |
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PKT_FIELD(vsk, peer_waiting_write_detected) = false; |
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} |
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static void vmci_transport_notify_pkt_socket_destruct(struct vsock_sock *vsk) |
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{ |
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PKT_FIELD(vsk, write_notify_window) = PAGE_SIZE; |
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PKT_FIELD(vsk, write_notify_min_window) = PAGE_SIZE; |
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PKT_FIELD(vsk, peer_waiting_write) = false; |
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PKT_FIELD(vsk, peer_waiting_write_detected) = false; |
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} |
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static int |
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vmci_transport_notify_pkt_poll_in(struct sock *sk, |
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size_t target, bool *data_ready_now) |
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{ |
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struct vsock_sock *vsk = vsock_sk(sk); |
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if (vsock_stream_has_data(vsk)) { |
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*data_ready_now = true; |
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} else { |
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/* We can't read right now because there is nothing in the |
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* queue. Ask for notifications when there is something to |
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* read. |
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*/ |
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if (sk->sk_state == TCP_ESTABLISHED) |
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vsock_block_update_write_window(sk); |
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*data_ready_now = false; |
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} |
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return 0; |
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} |
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static int |
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vmci_transport_notify_pkt_poll_out(struct sock *sk, |
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size_t target, bool *space_avail_now) |
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{ |
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s64 produce_q_free_space; |
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struct vsock_sock *vsk = vsock_sk(sk); |
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produce_q_free_space = vsock_stream_has_space(vsk); |
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if (produce_q_free_space > 0) { |
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*space_avail_now = true; |
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return 0; |
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} else if (produce_q_free_space == 0) { |
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/* This is a connected socket but we can't currently send data. |
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* Nothing else to do. |
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*/ |
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*space_avail_now = false; |
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} |
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return 0; |
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} |
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static int |
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vmci_transport_notify_pkt_recv_init( |
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struct sock *sk, |
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size_t target, |
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struct vmci_transport_recv_notify_data *data) |
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{ |
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struct vsock_sock *vsk = vsock_sk(sk); |
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data->consume_head = 0; |
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data->produce_tail = 0; |
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data->notify_on_block = false; |
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if (PKT_FIELD(vsk, write_notify_min_window) < target + 1) { |
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PKT_FIELD(vsk, write_notify_min_window) = target + 1; |
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if (PKT_FIELD(vsk, write_notify_window) < |
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PKT_FIELD(vsk, write_notify_min_window)) { |
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/* If the current window is smaller than the new |
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* minimal window size, we need to reevaluate whether |
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* we need to notify the sender. If the number of ready |
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* bytes are smaller than the new window, we need to |
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* send a notification to the sender before we block. |
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*/ |
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PKT_FIELD(vsk, write_notify_window) = |
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PKT_FIELD(vsk, write_notify_min_window); |
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data->notify_on_block = true; |
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} |
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} |
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return 0; |
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} |
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static int |
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vmci_transport_notify_pkt_recv_pre_block( |
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struct sock *sk, |
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size_t target, |
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struct vmci_transport_recv_notify_data *data) |
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{ |
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int err = 0; |
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vsock_block_update_write_window(sk); |
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if (data->notify_on_block) { |
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err = vmci_transport_send_read_notification(sk); |
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if (err < 0) |
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return err; |
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data->notify_on_block = false; |
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} |
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return err; |
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} |
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static int |
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vmci_transport_notify_pkt_recv_post_dequeue( |
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struct sock *sk, |
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size_t target, |
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ssize_t copied, |
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bool data_read, |
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struct vmci_transport_recv_notify_data *data) |
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{ |
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struct vsock_sock *vsk; |
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int err; |
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bool was_full = false; |
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u64 free_space; |
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vsk = vsock_sk(sk); |
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err = 0; |
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if (data_read) { |
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smp_mb(); |
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free_space = |
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vmci_qpair_consume_free_space(vmci_trans(vsk)->qpair); |
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was_full = free_space == copied; |
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if (was_full) |
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PKT_FIELD(vsk, peer_waiting_write) = true; |
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err = vmci_transport_send_read_notification(sk); |
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if (err < 0) |
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return err; |
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/* See the comment in |
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* vmci_transport_notify_pkt_send_post_enqueue(). |
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*/ |
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sk->sk_data_ready(sk); |
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} |
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return err; |
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} |
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static int |
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vmci_transport_notify_pkt_send_init( |
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struct sock *sk, |
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struct vmci_transport_send_notify_data *data) |
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{ |
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data->consume_head = 0; |
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data->produce_tail = 0; |
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return 0; |
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} |
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static int |
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vmci_transport_notify_pkt_send_post_enqueue( |
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struct sock *sk, |
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ssize_t written, |
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struct vmci_transport_send_notify_data *data) |
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{ |
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int err = 0; |
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struct vsock_sock *vsk; |
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bool sent_wrote = false; |
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bool was_empty; |
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int retries = 0; |
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vsk = vsock_sk(sk); |
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smp_mb(); |
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was_empty = |
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vmci_qpair_produce_buf_ready(vmci_trans(vsk)->qpair) == written; |
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if (was_empty) { |
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while (!(vsk->peer_shutdown & RCV_SHUTDOWN) && |
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!sent_wrote && |
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retries < VMCI_TRANSPORT_MAX_DGRAM_RESENDS) { |
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err = vmci_transport_send_wrote(sk); |
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if (err >= 0) |
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sent_wrote = true; |
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retries++; |
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} |
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} |
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if (retries >= VMCI_TRANSPORT_MAX_DGRAM_RESENDS && !sent_wrote) { |
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pr_err("%p unable to send wrote notification to peer\n", |
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sk); |
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return err; |
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} |
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return err; |
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} |
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static void |
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vmci_transport_notify_pkt_handle_pkt( |
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struct sock *sk, |
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struct vmci_transport_packet *pkt, |
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bool bottom_half, |
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struct sockaddr_vm *dst, |
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struct sockaddr_vm *src, bool *pkt_processed) |
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{ |
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bool processed = false; |
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switch (pkt->type) { |
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case VMCI_TRANSPORT_PACKET_TYPE_WROTE: |
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vmci_transport_handle_wrote(sk, pkt, bottom_half, dst, src); |
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processed = true; |
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break; |
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case VMCI_TRANSPORT_PACKET_TYPE_READ: |
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vmci_transport_handle_read(sk, pkt, bottom_half, dst, src); |
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processed = true; |
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break; |
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} |
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if (pkt_processed) |
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*pkt_processed = processed; |
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} |
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static void vmci_transport_notify_pkt_process_request(struct sock *sk) |
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{ |
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struct vsock_sock *vsk = vsock_sk(sk); |
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PKT_FIELD(vsk, write_notify_window) = vmci_trans(vsk)->consume_size; |
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if (vmci_trans(vsk)->consume_size < |
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PKT_FIELD(vsk, write_notify_min_window)) |
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PKT_FIELD(vsk, write_notify_min_window) = |
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vmci_trans(vsk)->consume_size; |
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} |
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static void vmci_transport_notify_pkt_process_negotiate(struct sock *sk) |
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{ |
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struct vsock_sock *vsk = vsock_sk(sk); |
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PKT_FIELD(vsk, write_notify_window) = vmci_trans(vsk)->consume_size; |
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if (vmci_trans(vsk)->consume_size < |
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PKT_FIELD(vsk, write_notify_min_window)) |
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PKT_FIELD(vsk, write_notify_min_window) = |
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vmci_trans(vsk)->consume_size; |
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} |
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static int |
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vmci_transport_notify_pkt_recv_pre_dequeue( |
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struct sock *sk, |
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size_t target, |
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struct vmci_transport_recv_notify_data *data) |
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{ |
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return 0; /* NOP for QState. */ |
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} |
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static int |
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vmci_transport_notify_pkt_send_pre_block( |
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struct sock *sk, |
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struct vmci_transport_send_notify_data *data) |
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{ |
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return 0; /* NOP for QState. */ |
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} |
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static int |
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vmci_transport_notify_pkt_send_pre_enqueue( |
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struct sock *sk, |
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struct vmci_transport_send_notify_data *data) |
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{ |
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return 0; /* NOP for QState. */ |
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} |
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/* Socket always on control packet based operations. */ |
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const struct vmci_transport_notify_ops vmci_transport_notify_pkt_q_state_ops = { |
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.socket_init = vmci_transport_notify_pkt_socket_init, |
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.socket_destruct = vmci_transport_notify_pkt_socket_destruct, |
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.poll_in = vmci_transport_notify_pkt_poll_in, |
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.poll_out = vmci_transport_notify_pkt_poll_out, |
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.handle_notify_pkt = vmci_transport_notify_pkt_handle_pkt, |
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.recv_init = vmci_transport_notify_pkt_recv_init, |
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.recv_pre_block = vmci_transport_notify_pkt_recv_pre_block, |
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.recv_pre_dequeue = vmci_transport_notify_pkt_recv_pre_dequeue, |
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.recv_post_dequeue = vmci_transport_notify_pkt_recv_post_dequeue, |
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.send_init = vmci_transport_notify_pkt_send_init, |
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.send_pre_block = vmci_transport_notify_pkt_send_pre_block, |
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.send_pre_enqueue = vmci_transport_notify_pkt_send_pre_enqueue, |
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.send_post_enqueue = vmci_transport_notify_pkt_send_post_enqueue, |
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.process_request = vmci_transport_notify_pkt_process_request, |
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.process_negotiate = vmci_transport_notify_pkt_process_negotiate, |
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};
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