[PATCH 5/5] hv: vss: use wrappers to propagate state

["K. Y. Srinivasan" <kys@microsoft.com>]

From: Olaf Hering <olaf@aepfle.de>

The "state" is used by several threads of execution.
Propagate the state to make changes visible. Also propagate context
change in vss_on_msg.

Signed-off-by: Olaf Hering <olaf@aepfle.de>
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
---
 drivers/hv/hv_snapshot.c |   37 ++++++++++++++++++++-----------------
 1 files changed, 20 insertions(+), 17 deletions(-)

diff --git a/drivers/hv/hv_snapshot.c b/drivers/hv/hv_snapshot.c
index 815405f..f3cb822 100644
--- a/drivers/hv/hv_snapshot.c
+++ b/drivers/hv/hv_snapshot.c
@@ -48,7 +48,7 @@
  */
 
 static struct {
-	int state;   /* hvutil_device_state */
+	enum hvutil_device_state state;
 	int recv_len; /* number of bytes received. */
 	struct vmbus_channel *recv_channel; /* chn we got the request */
 	u64 recv_req_id; /* request ID. */
@@ -64,6 +64,9 @@ static void vss_respond_to_host(int error);
  */
 static int dm_reg_value;
 
+#define vss_get_state() hvutil_device_get_state(&vss_transaction.state)
+#define vss_set_state(s) hvutil_device_set_state(&vss_transaction.state, s)
+
 static const char vss_devname[] = "vmbus/hv_vss";
 static __u8 *recv_buffer;
 static struct hvutil_transport *hvt;
@@ -87,8 +90,8 @@ static void vss_timeout_func(struct work_struct *dummy)
 	vss_respond_to_host(HV_E_FAIL);
 
 	/* Transaction is finished, reset the state. */
-	if (vss_transaction.state > HVUTIL_READY)
-		vss_transaction.state = HVUTIL_READY;
+	if (vss_get_state() > HVUTIL_READY)
+		vss_set_state(HVUTIL_READY);
 
 	hv_poll_channel(vss_transaction.vss_context,
 			hv_vss_onchannelcallback);
@@ -112,7 +115,7 @@ static int vss_handle_handshake(struct hv_vss_msg *vss_msg)
 	default:
 		return -EINVAL;
 	}
-	vss_transaction.state = HVUTIL_READY;
+	vss_set_state(HVUTIL_READY);
 	pr_debug("VSS: userspace daemon ver. %d registered\n", dm_reg_value);
 	return 0;
 }
@@ -130,15 +133,15 @@ static int vss_on_msg(void *msg, int len)
 		 * Don't process registration messages if we're in the middle
 		 * of a transaction processing.
 		 */
-		if (vss_transaction.state > HVUTIL_READY)
+		if (vss_get_state() > HVUTIL_READY)
 			return -EINVAL;
 		return vss_handle_handshake(vss_msg);
-	} else if (vss_transaction.state == HVUTIL_USERSPACE_REQ) {
-		vss_transaction.state = HVUTIL_USERSPACE_RECV;
+	} else if (vss_get_state() == HVUTIL_USERSPACE_REQ) {
+		vss_set_state(HVUTIL_USERSPACE_RECV);
 		if (cancel_delayed_work_sync(&vss_timeout_work)) {
 			vss_respond_to_host(vss_msg->error);
 			/* Transaction is finished, reset the state. */
-			vss_transaction.state = HVUTIL_READY;
+			vss_set_state(HVUTIL_READY);
 			hv_poll_channel(vss_transaction.vss_context,
 					hv_vss_onchannelcallback);
 		}
@@ -158,7 +161,7 @@ static void vss_send_op(struct work_struct *dummy)
 	struct hv_vss_msg *vss_msg;
 
 	/* The transaction state is wrong. */
-	if (vss_transaction.state != HVUTIL_HOSTMSG_RECEIVED)
+	if (vss_get_state() != HVUTIL_HOSTMSG_RECEIVED)
 		return;
 
 	vss_msg = kzalloc(sizeof(*vss_msg), GFP_KERNEL);
@@ -167,13 +170,13 @@ static void vss_send_op(struct work_struct *dummy)
 
 	vss_msg->vss_hdr.operation = op;
 
-	vss_transaction.state = HVUTIL_USERSPACE_REQ;
+	vss_set_state(HVUTIL_USERSPACE_REQ);
 	rc = hvutil_transport_send(hvt, vss_msg, sizeof(*vss_msg));
 	if (rc) {
 		pr_warn("VSS: failed to communicate to the daemon: %d\n", rc);
 		if (cancel_delayed_work_sync(&vss_timeout_work)) {
 			vss_respond_to_host(HV_E_FAIL);
-			vss_transaction.state = HVUTIL_READY;
+			vss_set_state(HVUTIL_READY);
 		}
 	}
 
@@ -238,7 +241,7 @@ void hv_vss_onchannelcallback(void *context)
 	struct icmsg_hdr *icmsghdrp;
 	struct icmsg_negotiate *negop = NULL;
 
-	if (vss_transaction.state > HVUTIL_READY) {
+	if (vss_get_state() > HVUTIL_READY) {
 		/*
 		 * We will defer processing this callback once
 		 * the current transaction is complete.
@@ -288,12 +291,12 @@ void hv_vss_onchannelcallback(void *context)
 				 */
 			case VSS_OP_FREEZE:
 			case VSS_OP_THAW:
-				if (vss_transaction.state < HVUTIL_READY) {
+				if (vss_get_state() < HVUTIL_READY) {
 					/* Userspace is not registered yet */
 					vss_respond_to_host(HV_E_FAIL);
 					return;
 				}
-				vss_transaction.state = HVUTIL_HOSTMSG_RECEIVED;
+				vss_set_state(HVUTIL_HOSTMSG_RECEIVED);
 				schedule_work(&vss_send_op_work);
 				schedule_delayed_work(&vss_timeout_work,
 						      VSS_USERSPACE_TIMEOUT);
@@ -332,7 +335,7 @@ static void vss_on_reset(void)
 {
 	if (cancel_delayed_work_sync(&vss_timeout_work))
 		vss_respond_to_host(HV_E_FAIL);
-	vss_transaction.state = HVUTIL_DEVICE_INIT;
+	vss_set_state(HVUTIL_DEVICE_INIT);
 }
 
 int
@@ -346,7 +349,7 @@ hv_vss_init(struct hv_util_service *srv)
 	 * Defer processing channel callbacks until the daemon
 	 * has registered.
 	 */
-	vss_transaction.state = HVUTIL_DEVICE_INIT;
+	vss_set_state(HVUTIL_DEVICE_INIT);
 
 	hvt = hvutil_transport_init(vss_devname, CN_VSS_IDX, CN_VSS_VAL,
 				    vss_on_msg, vss_on_reset);
@@ -358,7 +361,7 @@ hv_vss_init(struct hv_util_service *srv)
 
 void hv_vss_deinit(void)
 {
-	vss_transaction.state = HVUTIL_DEVICE_DYING;
+	vss_set_state(HVUTIL_DEVICE_DYING);
 	cancel_delayed_work_sync(&vss_timeout_work);
 	cancel_work_sync(&vss_send_op_work);
 	hvutil_transport_destroy(hvt);
-- 
1.7.4.1