342 строки
8.6 KiB
C
342 строки
8.6 KiB
C
/*
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* An implementation of key value pair (KVP) functionality for Linux.
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*
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*
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* Copyright (C) 2010, Novell, Inc.
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* Author : K. Y. Srinivasan <ksrinivasan@novell.com>
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License version 2 as published
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* by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
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* NON INFRINGEMENT. See the GNU General Public License for more
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* details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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*
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*/
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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#include <linux/net.h>
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#include <linux/nls.h>
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#include <linux/connector.h>
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#include <linux/workqueue.h>
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#include <linux/hyperv.h>
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#include "hv_kvp.h"
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/*
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* Global state maintained for transaction that is being processed.
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* Note that only one transaction can be active at any point in time.
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*
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* This state is set when we receive a request from the host; we
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* cleanup this state when the transaction is completed - when we respond
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* to the host with the key value.
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*/
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static struct {
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bool active; /* transaction status - active or not */
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int recv_len; /* number of bytes received. */
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int index; /* current index */
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struct vmbus_channel *recv_channel; /* chn we got the request */
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u64 recv_req_id; /* request ID. */
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} kvp_transaction;
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static void kvp_send_key(struct work_struct *dummy);
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#define TIMEOUT_FIRED 1
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static void kvp_respond_to_host(char *key, char *value, int error);
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static void kvp_work_func(struct work_struct *dummy);
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static void kvp_register(void);
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static DECLARE_DELAYED_WORK(kvp_work, kvp_work_func);
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static DECLARE_WORK(kvp_sendkey_work, kvp_send_key);
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static struct cb_id kvp_id = { CN_KVP_IDX, CN_KVP_VAL };
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static const char kvp_name[] = "kvp_kernel_module";
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static u8 *recv_buffer;
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/*
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* Register the kernel component with the user-level daemon.
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* As part of this registration, pass the LIC version number.
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*/
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static void
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kvp_register(void)
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{
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struct cn_msg *msg;
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msg = kzalloc(sizeof(*msg) + strlen(HV_DRV_VERSION) + 1 , GFP_ATOMIC);
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if (msg) {
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msg->id.idx = CN_KVP_IDX;
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msg->id.val = CN_KVP_VAL;
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msg->seq = KVP_REGISTER;
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strcpy(msg->data, HV_DRV_VERSION);
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msg->len = strlen(HV_DRV_VERSION) + 1;
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cn_netlink_send(msg, 0, GFP_ATOMIC);
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kfree(msg);
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}
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}
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static void
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kvp_work_func(struct work_struct *dummy)
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{
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/*
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* If the timer fires, the user-mode component has not responded;
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* process the pending transaction.
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*/
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kvp_respond_to_host("Unknown key", "Guest timed out", TIMEOUT_FIRED);
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}
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/*
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* Callback when data is received from user mode.
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*/
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static void
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kvp_cn_callback(struct cn_msg *msg, struct netlink_skb_parms *nsp)
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{
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struct hv_ku_msg *message;
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message = (struct hv_ku_msg *)msg->data;
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if (msg->seq == KVP_REGISTER) {
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pr_info("KVP: user-mode registering done.\n");
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kvp_register();
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}
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if (msg->seq == KVP_USER_SET) {
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/*
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* Complete the transaction by forwarding the key value
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* to the host. But first, cancel the timeout.
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*/
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if (cancel_delayed_work_sync(&kvp_work))
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kvp_respond_to_host(message->kvp_key,
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message->kvp_value,
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!strlen(message->kvp_key));
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}
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}
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static void
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kvp_send_key(struct work_struct *dummy)
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{
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struct cn_msg *msg;
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int index = kvp_transaction.index;
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msg = kzalloc(sizeof(*msg) + sizeof(struct hv_kvp_msg) , GFP_ATOMIC);
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if (msg) {
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msg->id.idx = CN_KVP_IDX;
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msg->id.val = CN_KVP_VAL;
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msg->seq = KVP_KERNEL_GET;
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((struct hv_ku_msg *)msg->data)->kvp_index = index;
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msg->len = sizeof(struct hv_ku_msg);
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cn_netlink_send(msg, 0, GFP_ATOMIC);
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kfree(msg);
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}
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return;
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}
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/*
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* Send a response back to the host.
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*/
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static void
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kvp_respond_to_host(char *key, char *value, int error)
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{
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struct hv_kvp_msg *kvp_msg;
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struct hv_kvp_msg_enumerate *kvp_data;
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char *key_name;
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struct icmsg_hdr *icmsghdrp;
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int keylen, valuelen;
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u32 buf_len;
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struct vmbus_channel *channel;
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u64 req_id;
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/*
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* If a transaction is not active; log and return.
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*/
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if (!kvp_transaction.active) {
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/*
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* This is a spurious call!
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*/
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pr_warn("KVP: Transaction not active\n");
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return;
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}
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/*
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* Copy the global state for completing the transaction. Note that
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* only one transaction can be active at a time.
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*/
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buf_len = kvp_transaction.recv_len;
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channel = kvp_transaction.recv_channel;
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req_id = kvp_transaction.recv_req_id;
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kvp_transaction.active = false;
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if (channel->onchannel_callback == NULL)
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/*
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* We have raced with util driver being unloaded;
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* silently return.
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*/
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return;
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icmsghdrp = (struct icmsg_hdr *)
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&recv_buffer[sizeof(struct vmbuspipe_hdr)];
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kvp_msg = (struct hv_kvp_msg *)
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&recv_buffer[sizeof(struct vmbuspipe_hdr) +
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sizeof(struct icmsg_hdr)];
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kvp_data = &kvp_msg->kvp_data;
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key_name = key;
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/*
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* If the error parameter is set, terminate the host's enumeration.
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*/
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if (error) {
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/*
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* We don't support this index or the we have timedout;
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* terminate the host-side iteration by returning an error.
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*/
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icmsghdrp->status = HV_E_FAIL;
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goto response_done;
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}
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/*
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* The windows host expects the key/value pair to be encoded
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* in utf16.
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*/
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keylen = utf8s_to_utf16s(key_name, strlen(key_name), UTF16_HOST_ENDIAN,
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(wchar_t *) kvp_data->data.key,
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HV_KVP_EXCHANGE_MAX_KEY_SIZE / 2);
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kvp_data->data.key_size = 2*(keylen + 1); /* utf16 encoding */
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valuelen = utf8s_to_utf16s(value, strlen(value), UTF16_HOST_ENDIAN,
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(wchar_t *) kvp_data->data.value,
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HV_KVP_EXCHANGE_MAX_VALUE_SIZE / 2);
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kvp_data->data.value_size = 2*(valuelen + 1); /* utf16 encoding */
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kvp_data->data.value_type = REG_SZ; /* all our values are strings */
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icmsghdrp->status = HV_S_OK;
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response_done:
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icmsghdrp->icflags = ICMSGHDRFLAG_TRANSACTION | ICMSGHDRFLAG_RESPONSE;
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vmbus_sendpacket(channel, recv_buffer, buf_len, req_id,
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VM_PKT_DATA_INBAND, 0);
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}
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/*
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* This callback is invoked when we get a KVP message from the host.
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* The host ensures that only one KVP transaction can be active at a time.
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* KVP implementation in Linux needs to forward the key to a user-mde
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* component to retrive the corresponding value. Consequently, we cannot
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* respond to the host in the conext of this callback. Since the host
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* guarantees that at most only one transaction can be active at a time,
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* we stash away the transaction state in a set of global variables.
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*/
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void hv_kvp_onchannelcallback(void *context)
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{
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struct vmbus_channel *channel = context;
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u32 recvlen;
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u64 requestid;
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struct hv_kvp_msg *kvp_msg;
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struct hv_kvp_msg_enumerate *kvp_data;
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struct icmsg_hdr *icmsghdrp;
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struct icmsg_negotiate *negop = NULL;
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vmbus_recvpacket(channel, recv_buffer, PAGE_SIZE, &recvlen, &requestid);
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if (recvlen > 0) {
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icmsghdrp = (struct icmsg_hdr *)&recv_buffer[
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sizeof(struct vmbuspipe_hdr)];
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if (icmsghdrp->icmsgtype == ICMSGTYPE_NEGOTIATE) {
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vmbus_prep_negotiate_resp(icmsghdrp, negop, recv_buffer);
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} else {
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kvp_msg = (struct hv_kvp_msg *)&recv_buffer[
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sizeof(struct vmbuspipe_hdr) +
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sizeof(struct icmsg_hdr)];
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kvp_data = &kvp_msg->kvp_data;
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/*
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* We only support the "get" operation on
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* "KVP_POOL_AUTO" pool.
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*/
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if ((kvp_msg->kvp_hdr.pool != KVP_POOL_AUTO) ||
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(kvp_msg->kvp_hdr.operation !=
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KVP_OP_ENUMERATE)) {
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icmsghdrp->status = HV_E_FAIL;
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goto callback_done;
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}
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/*
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* Stash away this global state for completing the
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* transaction; note transactions are serialized.
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*/
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kvp_transaction.recv_len = recvlen;
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kvp_transaction.recv_channel = channel;
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kvp_transaction.recv_req_id = requestid;
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kvp_transaction.active = true;
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kvp_transaction.index = kvp_data->index;
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/*
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* Get the information from the
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* user-mode component.
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* component. This transaction will be
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* completed when we get the value from
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* the user-mode component.
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* Set a timeout to deal with
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* user-mode not responding.
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*/
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schedule_work(&kvp_sendkey_work);
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schedule_delayed_work(&kvp_work, 5*HZ);
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return;
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}
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callback_done:
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icmsghdrp->icflags = ICMSGHDRFLAG_TRANSACTION
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| ICMSGHDRFLAG_RESPONSE;
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vmbus_sendpacket(channel, recv_buffer,
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recvlen, requestid,
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VM_PKT_DATA_INBAND, 0);
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}
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}
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int
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hv_kvp_init(struct hv_util_service *srv)
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{
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int err;
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err = cn_add_callback(&kvp_id, kvp_name, kvp_cn_callback);
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if (err)
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return err;
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recv_buffer = srv->recv_buffer;
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return 0;
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}
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void hv_kvp_deinit(void)
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{
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cn_del_callback(&kvp_id);
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cancel_delayed_work_sync(&kvp_work);
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cancel_work_sync(&kvp_sendkey_work);
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}
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