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path: root/drivers/hv/hv_kvp.c
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Diffstat (limited to 'drivers/hv/hv_kvp.c')
-rw-r--r--drivers/hv/hv_kvp.c87
1 files changed, 49 insertions, 38 deletions
diff --git a/drivers/hv/hv_kvp.c b/drivers/hv/hv_kvp.c
index 14c62e2bc0c9..a70d20262540 100644
--- a/drivers/hv/hv_kvp.c
+++ b/drivers/hv/hv_kvp.c
@@ -46,16 +46,21 @@
#define WIN8_SRV_VERSION (WIN8_SRV_MAJOR << 16 | WIN8_SRV_MINOR)
/*
- * Global state maintained for transaction that is being processed.
- * Note that only one transaction can be active at any point in time.
+ * Global state maintained for transaction that is being processed. For a class
+ * of integration services, including the "KVP service", the specified protocol
+ * is a "request/response" protocol which means that there can only be single
+ * outstanding transaction from the host at any given point in time. We use
+ * this to simplify memory management in this driver - we cache and process
+ * only one message at a time.
*
- * This state is set when we receive a request from the host; we
- * cleanup this state when the transaction is completed - when we respond
- * to the host with the key value.
+ * While the request/response protocol is guaranteed by the host, we further
+ * ensure this by serializing packet processing in this driver - we do not
+ * read additional packets from the VMBUs until the current packet is fully
+ * handled.
*/
static struct {
- bool active; /* transaction status - active or not */
+ int state; /* hvutil_device_state */
int recv_len; /* number of bytes received. */
struct hv_kvp_msg *kvp_msg; /* current message */
struct vmbus_channel *recv_channel; /* chn we got the request */
@@ -64,13 +69,6 @@ static struct {
} kvp_transaction;
/*
- * Before we can accept KVP messages from the host, we need
- * to handshake with the user level daemon. This state tracks
- * if we are in the handshake phase.
- */
-static bool in_hand_shake = true;
-
-/*
* This state maintains the version number registered by the daemon.
*/
static int dm_reg_value;
@@ -126,6 +124,13 @@ static void kvp_timeout_func(struct work_struct *dummy)
* process the pending transaction.
*/
kvp_respond_to_host(NULL, HV_E_FAIL);
+
+ /* Transaction is finished, reset the state. */
+ if (kvp_transaction.state > HVUTIL_READY)
+ kvp_transaction.state = HVUTIL_READY;
+
+ hv_poll_channel(kvp_transaction.kvp_context,
+ hv_kvp_onchannelcallback);
}
static int kvp_handle_handshake(struct hv_kvp_msg *msg)
@@ -154,9 +159,7 @@ static int kvp_handle_handshake(struct hv_kvp_msg *msg)
*/
pr_info("KVP: user-mode registering done.\n");
kvp_register(dm_reg_value);
- kvp_transaction.active = false;
- hv_poll_channel(kvp_transaction.kvp_context,
- hv_kvp_onchannelcallback);
+ kvp_transaction.state = HVUTIL_READY;
}
return ret;
}
@@ -180,12 +183,16 @@ kvp_cn_callback(struct cn_msg *msg, struct netlink_skb_parms *nsp)
* with the daemon; handle that first.
*/
- if (in_hand_shake) {
- if (kvp_handle_handshake(message))
- in_hand_shake = false;
+ if (kvp_transaction.state < HVUTIL_READY) {
+ kvp_handle_handshake(message);
return;
}
+ /* We didn't send anything to userspace so the reply is spurious */
+ if (kvp_transaction.state < HVUTIL_USERSPACE_REQ)
+ return;
+ kvp_transaction.state = HVUTIL_USERSPACE_RECV;
+
/*
* Based on the version of the daemon, we propagate errors from the
* daemon differently.
@@ -215,8 +222,12 @@ kvp_cn_callback(struct cn_msg *msg, struct netlink_skb_parms *nsp)
* Complete the transaction by forwarding the key value
* to the host. But first, cancel the timeout.
*/
- if (cancel_delayed_work_sync(&kvp_timeout_work))
+ if (cancel_delayed_work_sync(&kvp_timeout_work)) {
kvp_respond_to_host(message, error);
+ kvp_transaction.state = HVUTIL_READY;
+ hv_poll_channel(kvp_transaction.kvp_context,
+ hv_kvp_onchannelcallback);
+ }
}
@@ -342,6 +353,10 @@ kvp_send_key(struct work_struct *dummy)
__u64 val64;
int rc;
+ /* The transaction state is wrong. */
+ if (kvp_transaction.state != HVUTIL_HOSTMSG_RECEIVED)
+ return;
+
msg = kzalloc(sizeof(*msg) + sizeof(struct hv_kvp_msg) , GFP_ATOMIC);
if (!msg)
return;
@@ -437,11 +452,14 @@ kvp_send_key(struct work_struct *dummy)
}
msg->len = sizeof(struct hv_kvp_msg);
+ kvp_transaction.state = HVUTIL_USERSPACE_REQ;
rc = cn_netlink_send(msg, 0, 0, GFP_ATOMIC);
if (rc) {
pr_debug("KVP: failed to communicate to the daemon: %d\n", rc);
- if (cancel_delayed_work_sync(&kvp_timeout_work))
+ if (cancel_delayed_work_sync(&kvp_timeout_work)) {
kvp_respond_to_host(message, HV_E_FAIL);
+ kvp_transaction.state = HVUTIL_READY;
+ }
}
kfree(msg);
@@ -469,17 +487,6 @@ kvp_respond_to_host(struct hv_kvp_msg *msg_to_host, int error)
int ret;
/*
- * If a transaction is not active; log and return.
- */
-
- if (!kvp_transaction.active) {
- /*
- * This is a spurious call!
- */
- pr_warn("KVP: Transaction not active\n");
- return;
- }
- /*
* Copy the global state for completing the transaction. Note that
* only one transaction can be active at a time.
*/
@@ -488,8 +495,6 @@ kvp_respond_to_host(struct hv_kvp_msg *msg_to_host, int error)
channel = kvp_transaction.recv_channel;
req_id = kvp_transaction.recv_req_id;
- kvp_transaction.active = false;
-
icmsghdrp = (struct icmsg_hdr *)
&recv_buffer[sizeof(struct vmbuspipe_hdr)];
@@ -576,7 +581,6 @@ response_done:
vmbus_sendpacket(channel, recv_buffer, buf_len, req_id,
VM_PKT_DATA_INBAND, 0);
- hv_poll_channel(channel, hv_kvp_onchannelcallback);
}
/*
@@ -602,7 +606,7 @@ void hv_kvp_onchannelcallback(void *context)
int util_fw_version;
int kvp_srv_version;
- if (kvp_transaction.active) {
+ if (kvp_transaction.state > HVUTIL_READY) {
/*
* We will defer processing this callback once
* the current transaction is complete.
@@ -655,9 +659,15 @@ void hv_kvp_onchannelcallback(void *context)
kvp_transaction.recv_len = recvlen;
kvp_transaction.recv_channel = channel;
kvp_transaction.recv_req_id = requestid;
- kvp_transaction.active = true;
kvp_transaction.kvp_msg = kvp_msg;
+ if (kvp_transaction.state < HVUTIL_READY) {
+ /* Userspace is not registered yet */
+ kvp_respond_to_host(NULL, HV_E_FAIL);
+ return;
+ }
+ kvp_transaction.state = HVUTIL_HOSTMSG_RECEIVED;
+
/*
* Get the information from the
* user-mode component.
@@ -700,13 +710,14 @@ hv_kvp_init(struct hv_util_service *srv)
* Defer processing channel callbacks until the daemon
* has registered.
*/
- kvp_transaction.active = true;
+ kvp_transaction.state = HVUTIL_DEVICE_INIT;
return 0;
}
void hv_kvp_deinit(void)
{
+ kvp_transaction.state = HVUTIL_DEVICE_DYING;
cn_del_callback(&kvp_id);
cancel_delayed_work_sync(&kvp_timeout_work);
cancel_work_sync(&kvp_sendkey_work);