diff options
| -rw-r--r-- | drivers/hv/hv_kvp.c | 87 |
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); |