Drivers: hv: vmbus: Introduce a function to remove a rescinded offer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>

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+         * If the channel has been rescinded; process device removal.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;