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

Signed-off-by: Olaf Hering <o...@aepfle.de>
---
 drivers/hv/hv_kvp.c | 38 +++++++++++++++++++++-----------------
 1 file changed, 21 insertions(+), 17 deletions(-)

diff --git a/drivers/hv/hv_kvp.c b/drivers/hv/hv_kvp.c
index 74c38a9..f421691 100644
--- a/drivers/hv/hv_kvp.c
+++ b/drivers/hv/hv_kvp.c
@@ -61,7 +61,7 @@
  */
 
 static struct {
-       int state;   /* hvutil_device_state */
+       enum hvutil_device_state 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 */
@@ -74,6 +74,9 @@ static struct {
  */
 static int dm_reg_value;
 
+#define kvp_get_state() hvutil_device_get_state(&kvp_transaction.state)
+#define kvp_set_state(s) hvutil_device_set_state(&kvp_transaction.state, s)
+
 static void kvp_send_key(struct work_struct *dummy);
 
 
@@ -122,8 +125,8 @@ static void kvp_timeout_func(struct work_struct *dummy)
        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;
+       if (kvp_get_state() > HVUTIL_READY)
+               kvp_set_state(HVUTIL_READY);
 
        hv_poll_channel(kvp_transaction.kvp_context,
                        hv_kvp_onchannelcallback);
@@ -153,7 +156,7 @@ static int kvp_handle_handshake(struct hv_kvp_msg *msg)
        pr_debug("KVP: userspace daemon ver. %d registered\n",
                 KVP_OP_REGISTER);
        kvp_register(dm_reg_value);
-       kvp_transaction.state = HVUTIL_READY;
+       kvp_set_state(HVUTIL_READY);
 
        return 0;
 }
@@ -177,15 +180,15 @@ static int kvp_on_msg(void *msg, int len)
         * with the daemon; handle that first.
         */
 
-       if (kvp_transaction.state < HVUTIL_READY) {
+       if (kvp_get_state() < HVUTIL_READY) {
                return kvp_handle_handshake(message);
        }
 
        /* We didn't send anything to userspace so the reply is spurious */
-       if (kvp_transaction.state < HVUTIL_USERSPACE_REQ)
+       if (kvp_get_state() < HVUTIL_USERSPACE_REQ)
                return -EINVAL;
 
-       kvp_transaction.state = HVUTIL_USERSPACE_RECV;
+       kvp_set_state(HVUTIL_USERSPACE_RECV);
 
        /*
         * Based on the version of the daemon, we propagate errors from the
@@ -218,7 +221,7 @@ static int kvp_on_msg(void *msg, int len)
         */
        if (cancel_delayed_work_sync(&kvp_timeout_work)) {
                kvp_respond_to_host(message, error);
-               kvp_transaction.state = HVUTIL_READY;
+               kvp_set_state(HVUTIL_READY);
                hv_poll_channel(kvp_transaction.kvp_context,
                                hv_kvp_onchannelcallback);
        }
@@ -349,7 +352,7 @@ kvp_send_key(struct work_struct *dummy)
        int rc;
 
        /* The transaction state is wrong. */
-       if (kvp_transaction.state != HVUTIL_HOSTMSG_RECEIVED)
+       if (kvp_get_state() != HVUTIL_HOSTMSG_RECEIVED)
                return;
 
        message = kzalloc(sizeof(*message), GFP_KERNEL);
@@ -442,13 +445,13 @@ kvp_send_key(struct work_struct *dummy)
                        break;
        }
 
-       kvp_transaction.state = HVUTIL_USERSPACE_REQ;
+       kvp_set_state(HVUTIL_USERSPACE_REQ);
        rc = hvutil_transport_send(hvt, message, sizeof(*message));
        if (rc) {
                pr_debug("KVP: failed to communicate to the daemon: %d\n", rc);
                if (cancel_delayed_work_sync(&kvp_timeout_work)) {
                        kvp_respond_to_host(message, HV_E_FAIL);
-                       kvp_transaction.state = HVUTIL_READY;
+                       kvp_set_state(HVUTIL_READY);
                }
        }
 
@@ -596,12 +599,13 @@ void hv_kvp_onchannelcallback(void *context)
        int util_fw_version;
        int kvp_srv_version;
 
-       if (kvp_transaction.state > HVUTIL_READY) {
+       if (kvp_get_state() > HVUTIL_READY) {
                /*
                 * We will defer processing this callback once
                 * the current transaction is complete.
                 */
                kvp_transaction.kvp_context = context;
+               wmb();
                return;
        }
        kvp_transaction.kvp_context = NULL;
@@ -651,12 +655,12 @@ void hv_kvp_onchannelcallback(void *context)
                        kvp_transaction.recv_req_id = requestid;
                        kvp_transaction.kvp_msg = kvp_msg;
 
-                       if (kvp_transaction.state < HVUTIL_READY) {
+                       if (kvp_get_state() < HVUTIL_READY) {
                                /* Userspace is not registered yet */
                                kvp_respond_to_host(NULL, HV_E_FAIL);
                                return;
                        }
-                       kvp_transaction.state = HVUTIL_HOSTMSG_RECEIVED;
+                       kvp_set_state(HVUTIL_HOSTMSG_RECEIVED);
 
                        /*
                         * Get the information from the
@@ -688,7 +692,7 @@ static void kvp_on_reset(void)
 {
        if (cancel_delayed_work_sync(&kvp_timeout_work))
                kvp_respond_to_host(NULL, HV_E_FAIL);
-       kvp_transaction.state = HVUTIL_DEVICE_INIT;
+       kvp_set_state(HVUTIL_DEVICE_INIT);
 }
 
 int
@@ -702,7 +706,7 @@ hv_kvp_init(struct hv_util_service *srv)
         * Defer processing channel callbacks until the daemon
         * has registered.
         */
-       kvp_transaction.state = HVUTIL_DEVICE_INIT;
+       kvp_set_state(HVUTIL_DEVICE_INIT);
 
        hvt = hvutil_transport_init(kvp_devname, CN_KVP_IDX, CN_KVP_VAL,
                                    kvp_on_msg, kvp_on_reset);
@@ -714,7 +718,7 @@ hv_kvp_init(struct hv_util_service *srv)
 
 void hv_kvp_deinit(void)
 {
-       kvp_transaction.state = HVUTIL_DEVICE_DYING;
+       kvp_set_state(HVUTIL_DEVICE_DYING);
        cancel_delayed_work_sync(&kvp_timeout_work);
        cancel_work_sync(&kvp_sendkey_work);
        hvutil_transport_destroy(hvt);
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