From 34c6801e3310ad286c7bb42bc88d42926b8f99bf Mon Sep 17 00:00:00 2001 From: Dexuan Cui Date: Mon, 14 Dec 2015 16:01:49 -0800 Subject: [PATCH] Drivers: hv: vmbus: fix rescind-offer handling for device without a driver In the path vmbus_onoffer_rescind() -> vmbus_device_unregister() -> device_unregister() -> ... -> __device_release_driver(), we can see for a device without a driver loaded: dev->driver is NULL, so dev->bus->remove(dev), namely vmbus_remove(), isn't invoked. As a result, vmbus_remove() -> hv_process_channel_removal() isn't invoked and some cleanups(like sending a CHANNELMSG_RELID_RELEASED message to the host) aren't done. We can demo the issue this way: 1. rmmod hv_utils; 2. disable the Heartbeat Integration Service in Hyper-V Manager and lsvmbus shows the device disappears. 3. re-enable the Heartbeat in Hyper-V Manager and modprobe hv_utils, but lsvmbus shows the device can't appear again. This is because, the host thinks the VM hasn't released the relid, so can't re-offer the device to the VM. We can fix the issue by moving hv_process_channel_removal() from vmbus_close_internal() to vmbus_device_release(), since the latter is always invoked on device_unregister(), whether or not the dev has a driver loaded. Signed-off-by: Dexuan Cui Signed-off-by: K. Y. Srinivasan Signed-off-by: Greg Kroah-Hartman --- drivers/hv/channel.c | 6 ------ drivers/hv/channel_mgmt.c | 6 +++--- drivers/hv/vmbus_drv.c | 15 +++------------ 3 files changed, 6 insertions(+), 21 deletions(-) diff --git a/drivers/hv/channel.c b/drivers/hv/channel.c index 00e1be775908..77d2579d6124 100644 --- a/drivers/hv/channel.c +++ b/drivers/hv/channel.c @@ -575,12 +575,6 @@ static int vmbus_close_internal(struct vmbus_channel *channel) free_pages((unsigned long)channel->ringbuffer_pages, get_order(channel->ringbuffer_pagecount * PAGE_SIZE)); - /* - * If the channel has been rescinded; process device removal. - */ - if (channel->rescind) - hv_process_channel_removal(channel, - channel->offermsg.child_relid); out: tasklet_enable(tasklet); diff --git a/drivers/hv/channel_mgmt.c b/drivers/hv/channel_mgmt.c index dc4fb0bccb8d..7903acc3403e 100644 --- a/drivers/hv/channel_mgmt.c +++ b/drivers/hv/channel_mgmt.c @@ -191,6 +191,8 @@ void hv_process_channel_removal(struct vmbus_channel *channel, u32 relid) if (channel == NULL) return; + BUG_ON(!channel->rescind); + if (channel->target_cpu != get_cpu()) { put_cpu(); smp_call_function_single(channel->target_cpu, @@ -230,9 +232,7 @@ void vmbus_free_channels(void) list_for_each_entry_safe(channel, tmp, &vmbus_connection.chn_list, listentry) { - /* if we don't set rescind to true, vmbus_close_internal() - * won't invoke hv_process_channel_removal(). - */ + /* hv_process_channel_removal() needs this */ channel->rescind = true; vmbus_device_unregister(channel->device_obj); diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c index ab888a1abef8..f123bca77808 100644 --- a/drivers/hv/vmbus_drv.c +++ b/drivers/hv/vmbus_drv.c @@ -601,23 +601,11 @@ 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 { - 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; @@ -652,7 +640,10 @@ static void vmbus_shutdown(struct device *child_device) static void vmbus_device_release(struct device *device) { struct hv_device *hv_dev = device_to_hv_device(device); + struct vmbus_channel *channel = hv_dev->channel; + hv_process_channel_removal(channel, + channel->offermsg.child_relid); kfree(hv_dev); } -- 2.20.1