From ed6cfcc5fdf2ebca320b6f74c836e555e18216e1 Mon Sep 17 00:00:00 2001
From: "K. Y. Srinivasan" <kys@microsoft.com>
Date: Sat, 28 Feb 2015 11:18:17 -0800
Subject: [PATCH] Drivers: hv: vmbus: Introduce a function to remove a
 rescinded offer

In response to a rescind message, we need to remove the channel and the
corresponding device. Cleanup this code path by factoring out the code
to remove a channel.

Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/hv/channel.c      |  9 +++++++
 drivers/hv/channel_mgmt.c | 49 ++++++++++++++++++++++++---------------
 drivers/hv/vmbus_drv.c    | 11 ++++++++-
 include/linux/hyperv.h    |  1 +
 4 files changed, 50 insertions(+), 20 deletions(-)

diff --git a/drivers/hv/channel.c b/drivers/hv/channel.c
index bf0cf8f3bcaf..9b79aca7e565 100644
--- a/drivers/hv/channel.c
+++ b/drivers/hv/channel.c
@@ -501,6 +501,15 @@ static int vmbus_close_internal(struct vmbus_channel *channel)
 		put_cpu();
 	}
 
+	/*
+	 * If the channel has been rescinded; process device removal.
+	 */
+	if (channel->rescind) {
+		hv_process_channel_removal(channel,
+					   channel->offermsg.child_relid);
+		return 0;
+	}
+
 	/* Send a closing message */
 
 	msg = &channel->close_msg.msg;
diff --git a/drivers/hv/channel_mgmt.c b/drivers/hv/channel_mgmt.c
index 0ba6b5c303e6..b93389124ec4 100644
--- a/drivers/hv/channel_mgmt.c
+++ b/drivers/hv/channel_mgmt.c
@@ -207,33 +207,21 @@ static void percpu_channel_deq(void *arg)
 	list_del(&channel->percpu_list);
 }
 
-/*
- * vmbus_process_rescind_offer -
- * Rescind the offer by initiating a device removal
- */
-static void vmbus_process_rescind_offer(struct work_struct *work)
+
+void hv_process_channel_removal(struct vmbus_channel *channel, u32 relid)
 {
-	struct vmbus_channel *channel = container_of(work,
-						     struct vmbus_channel,
-						     work);
+	struct vmbus_channel_relid_released msg;
 	unsigned long flags;
 	struct vmbus_channel *primary_channel;
-	struct vmbus_channel_relid_released msg;
-	struct device *dev;
-
-	if (channel->device_obj) {
-		dev = get_device(&channel->device_obj->device);
-		if (dev) {
-			vmbus_device_unregister(channel->device_obj);
-			put_device(dev);
-		}
-	}
 
 	memset(&msg, 0, sizeof(struct vmbus_channel_relid_released));
-	msg.child_relid = channel->offermsg.child_relid;
+	msg.child_relid = relid;
 	msg.header.msgtype = CHANNELMSG_RELID_RELEASED;
 	vmbus_post_msg(&msg, sizeof(struct vmbus_channel_relid_released));
 
+	if (channel == NULL)
+		return;
+
 	if (channel->target_cpu != get_cpu()) {
 		put_cpu();
 		smp_call_function_single(channel->target_cpu,
@@ -256,6 +244,29 @@ static void vmbus_process_rescind_offer(struct work_struct *work)
 	free_channel(channel);
 }
 
+/*
+ * vmbus_process_rescind_offer -
+ * Rescind the offer by initiating a device removal
+ */
+static void vmbus_process_rescind_offer(struct work_struct *work)
+{
+	struct vmbus_channel *channel = container_of(work,
+						     struct vmbus_channel,
+						     work);
+	struct device *dev;
+
+	if (channel->device_obj) {
+		dev = get_device(&channel->device_obj->device);
+		if (dev) {
+			vmbus_device_unregister(channel->device_obj);
+			put_device(dev);
+		}
+	} else {
+		hv_process_channel_removal(channel,
+					   channel->offermsg.child_relid);
+	}
+}
+
 void vmbus_free_channels(void)
 {
 	struct vmbus_channel *channel;
diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c
index a12666d075ea..2b7b51d264f1 100644
--- a/drivers/hv/vmbus_drv.c
+++ b/drivers/hv/vmbus_drv.c
@@ -510,14 +510,23 @@ static int vmbus_remove(struct device *child_device)
 {
 	struct hv_driver *drv;
 	struct hv_device *dev = device_to_hv_device(child_device);
+	u32 relid = dev->channel->offermsg.child_relid;
 
 	if (child_device->driver) {
 		drv = drv_to_hv_drv(child_device->driver);
 		if (drv->remove)
 			drv->remove(dev);
-		else
+		else {
+			hv_process_channel_removal(dev->channel, relid);
 			pr_err("remove not set for driver %s\n",
 				dev_name(child_device));
+		}
+	} else {
+		/*
+		 * We don't have a driver for this device; deal with the
+		 * rescind message by removing the channel.
+		 */
+		hv_process_channel_removal(dev->channel, relid);
 	}
 
 	return 0;
diff --git a/include/linux/hyperv.h b/include/linux/hyperv.h
index 7d976ac01fac..dd92a854c700 100644
--- a/include/linux/hyperv.h
+++ b/include/linux/hyperv.h
@@ -1226,6 +1226,7 @@ void hv_kvp_onchannelcallback(void *);
 int hv_vss_init(struct hv_util_service *);
 void hv_vss_deinit(void);
 void hv_vss_onchannelcallback(void *);
+void hv_process_channel_removal(struct vmbus_channel *channel, u32 relid);
 
 extern struct resource hyperv_mmio;
 
-- 
2.20.1