rh7: Drivers: hv: vmbus: Fix a rescind handling bug

hv-rhel7.x/hv/channel.c

@@ -157,6 +157,7 @@ int vmbus_open(struct vmbus_channel *newchannel, u32 send_ringbuffer_size,
 	}
 
 	init_completion(&open_info->waitevent);
+	open_info->waiting_channel = newchannel;
 
 	open_msg = (struct vmbus_channel_open_channel *)open_info->msg;
 	open_msg->header.msgtype = CHANNELMSG_OPENCHANNEL;
@@ -195,6 +196,11 @@ int vmbus_open(struct vmbus_channel *newchannel, u32 send_ringbuffer_size,
 	list_del(&open_info->msglistentry);
 	spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
 
+	if (newchannel->rescind) {
+		err = -ENODEV;
+		goto error_free_gpadl;
+	}
+
 	if (open_info->response.open_result.status) {
 		err = -EAGAIN;
 		goto error_free_gpadl;
@@ -406,6 +412,7 @@ int vmbus_establish_gpadl(struct vmbus_channel *channel, void *kbuffer,
 		return ret;
 
 	init_completion(&msginfo->waitevent);
+	msginfo->waiting_channel = channel;
 
 	gpadlmsg = (struct vmbus_channel_gpadl_header *)msginfo->msg;
 	gpadlmsg->header.msgtype = CHANNELMSG_GPADL_HEADER;
@@ -442,6 +449,11 @@ int vmbus_establish_gpadl(struct vmbus_channel *channel, void *kbuffer,
 	}
 	wait_for_completion(&msginfo->waitevent);
 
+	if (channel->rescind) {
+		ret = -ENODEV;
+		goto cleanup;
+	}
+
 	/* At this point, we received the gpadl created msg */
 	*gpadl_handle = gpadlmsg->gpadl;
 
@@ -475,6 +487,7 @@ int vmbus_teardown_gpadl(struct vmbus_channel *channel, u32 gpadl_handle)
 		return -ENOMEM;
 
 	init_completion(&info->waitevent);
+	info->waiting_channel = channel;
 
 	msg = (struct vmbus_channel_gpadl_teardown *)info->msg;
 
@@ -494,6 +507,11 @@ int vmbus_teardown_gpadl(struct vmbus_channel *channel, u32 gpadl_handle)
 
 	wait_for_completion(&info->waitevent);
 
+	if (channel->rescind) {
+		ret = -ENODEV;
+		goto post_msg_err;
+	}
+
 post_msg_err:
 	spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
 	list_del(&info->msglistentry);

hv-rhel7.x/hv/channel_mgmt.c

@@ -146,6 +146,29 @@ static const struct {
 	{ HV_RDV_GUID	},
 };
 
+/*
+ * The rescinded channel may be blocked waiting for a response from the host;
+ * take care of that.
+ */
+static void vmbus_rescind_cleanup(struct vmbus_channel *channel)
+{
+	struct vmbus_channel_msginfo *msginfo;
+	unsigned long flags;
+
+
+	spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
+
+	list_for_each_entry(msginfo, &vmbus_connection.chn_msg_list,
+				msglistentry) {
+
+		if (msginfo->waiting_channel == channel) {
+			complete(&msginfo->waitevent);
+			break;
+		}
+	}
+	spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
+}
+
 static bool is_unsupported_vmbus_devs(const uuid_le *guid)
 {
 	int i;
@@ -807,6 +830,8 @@ static void vmbus_onoffer_rescind(struct vmbus_channel_message_header *hdr)
 	channel->rescind = true;
 	spin_unlock_irqrestore(&channel->lock, flags);
 
+	vmbus_rescind_cleanup(channel);
+
 	if (channel->device_obj) {
 		if (is_hvsock_channel(channel) &&
 		    channel->hvsock_event_callback) {

hv-rhel7.x/hv/include/linux/hyperv.h

@@ -628,6 +628,7 @@ struct vmbus_channel_msginfo {
 
 	/* Synchronize the request/response if needed */
 	struct completion  waitevent;
+	struct vmbus_channel *waiting_channel;
 	union {
 		struct vmbus_channel_version_supported version_supported;
 		struct vmbus_channel_open_result open_result;