[Patch v5 1/2] PCI: hv: Decouple the func definition in hv_dr_state from VSP message

[Patch v5 1/2] PCI: hv: Decouple the func definition in hv_dr_state from VSP message

[longli]

From: Long Li <longli@microsoft.com>

hv_dr_state is used to find present PCI devices on the bus. The structure
reuses struct pci_function_description from VSP message to describe a
device.

To prepare support for pci_function_description v2, decouple this
dependence in hv_dr_state so it can work with both v1 and v2 VSP messages.

There is no functionality change.

Signed-off-by: Long Li <longli@microsoft.com>
Reviewed-by: Michael Kelley <mikelley@microsoft.com>
---
Changes
v2: Changed some spaces to tabs, changed failure code to -ENOMEM
v3: Revised comment for function hv_pci_devices_present(), reformatted patch title
v4: Fixed spelling
v5: Rebased to current tree

 drivers/pci/controller/pci-hyperv.c | 100 +++++++++++++++++++++++++-----------
 1 file changed, 70 insertions(+), 30 deletions(-)

diff --git a/drivers/pci/controller/pci-hyperv.c b/drivers/pci/controller/pci-hyperv.c
index 15011a3..dea197f 100644
--- a/drivers/pci/controller/pci-hyperv.c
+++ b/drivers/pci/controller/pci-hyperv.c
@@ -505,10 +505,24 @@ struct hv_dr_work {
 	struct hv_pcibus_device *bus;
 };
 
+struct hv_pcidev_description {
+	u16	v_id;	/* vendor ID */
+	u16	d_id;	/* device ID */
+	u8	rev;
+	u8	prog_intf;
+	u8	subclass;
+	u8	base_class;
+	u32	subsystem_id;
+	union	win_slot_encoding win_slot;
+	u32	ser;	/* serial number */
+	u32	flags;
+	u16	virtual_numa_node;
+};
+
 struct hv_dr_state {
 	struct list_head list_entry;
 	u32 device_count;
-	struct pci_function_description func[0];
+	struct hv_pcidev_description func[0];
 };
 
 enum hv_pcichild_state {
@@ -525,7 +539,7 @@ struct hv_pci_dev {
 	refcount_t refs;
 	enum hv_pcichild_state state;
 	struct pci_slot *pci_slot;
-	struct pci_function_description desc;
+	struct hv_pcidev_description desc;
 	bool reported_missing;
 	struct hv_pcibus_device *hbus;
 	struct work_struct wrk;
@@ -1877,7 +1891,7 @@ static void q_resource_requirements(void *context, struct pci_response *resp,
  * Return: Pointer to the new tracking struct
  */
 static struct hv_pci_dev *new_pcichild_device(struct hv_pcibus_device *hbus,
-		struct pci_function_description *desc)
+		struct hv_pcidev_description *desc)
 {
 	struct hv_pci_dev *hpdev;
 	struct pci_child_message *res_req;
@@ -1988,7 +2002,7 @@ static void pci_devices_present_work(struct work_struct *work)
 {
 	u32 child_no;
 	bool found;
-	struct pci_function_description *new_desc;
+	struct hv_pcidev_description *new_desc;
 	struct hv_pci_dev *hpdev;
 	struct hv_pcibus_device *hbus;
 	struct list_head removed;
@@ -2107,17 +2121,15 @@ static void pci_devices_present_work(struct work_struct *work)
 }
 
 /**
- * hv_pci_devices_present() - Handles list of new children
+ * hv_pci_start_relations_work() - Queue work to start device discovery
  * @hbus:	Root PCI bus, as understood by this driver
- * @relations:	Packet from host listing children
+ * @dr:		The list of children returned from host
  *
- * This function is invoked whenever a new list of devices for
- * this bus appears.
+ * Return:  0 on success, -errno on failure
  */
-static void hv_pci_devices_present(struct hv_pcibus_device *hbus,
-				   struct pci_bus_relations *relations)
+static int hv_pci_start_relations_work(struct hv_pcibus_device *hbus,
+				       struct hv_dr_state *dr)
 {
-	struct hv_dr_state *dr;
 	struct hv_dr_work *dr_wrk;
 	unsigned long flags;
 	bool pending_dr;
@@ -2125,29 +2137,15 @@ static void hv_pci_devices_present(struct hv_pcibus_device *hbus,
 	if (hbus->state == hv_pcibus_removing) {
 		dev_info(&hbus->hdev->device,
 			 "PCI VMBus BUS_RELATIONS: ignored\n");
-		return;
+		return -ENOENT;
 	}
 
 	dr_wrk = kzalloc(sizeof(*dr_wrk), GFP_NOWAIT);
 	if (!dr_wrk)
-		return;
-
-	dr = kzalloc(offsetof(struct hv_dr_state, func) +
-		     (sizeof(struct pci_function_description) *
-		      (relations->device_count)), GFP_NOWAIT);
-	if (!dr)  {
-		kfree(dr_wrk);
-		return;
-	}
+		return -ENOMEM;
 
 	INIT_WORK(&dr_wrk->wrk, pci_devices_present_work);
 	dr_wrk->bus = hbus;
-	dr->device_count = relations->device_count;
-	if (dr->device_count != 0) {
-		memcpy(dr->func, relations->func,
-		       sizeof(struct pci_function_description) *
-		       dr->device_count);
-	}
 
 	spin_lock_irqsave(&hbus->device_list_lock, flags);
 	/*
@@ -2165,6 +2163,47 @@ static void hv_pci_devices_present(struct hv_pcibus_device *hbus,
 		get_hvpcibus(hbus);
 		queue_work(hbus->wq, &dr_wrk->wrk);
 	}
+
+	return 0;
+}
+
+/**
+ * hv_pci_devices_present() - Handle list of new children
+ * @hbus:      Root PCI bus, as understood by this driver
+ * @relations: Packet from host listing children
+ *
+ * Process a new list of devices on the bus. The list of devices is
+ * discovered by VSP and sent to us via VSP message PCI_BUS_RELATIONS,
+ * whenever a new list of devices for this bus appears.
+ */
+static void hv_pci_devices_present(struct hv_pcibus_device *hbus,
+				   struct pci_bus_relations *relations)
+{
+	struct hv_dr_state *dr;
+	int i;
+
+	dr = kzalloc(offsetof(struct hv_dr_state, func) +
+		     (sizeof(struct hv_pcidev_description) *
+		      (relations->device_count)), GFP_NOWAIT);
+
+	if (!dr)
+		return;
+
+	dr->device_count = relations->device_count;
+	for (i = 0; i < dr->device_count; i++) {
+		dr->func[i].v_id = relations->func[i].v_id;
+		dr->func[i].d_id = relations->func[i].d_id;
+		dr->func[i].rev = relations->func[i].rev;
+		dr->func[i].prog_intf = relations->func[i].prog_intf;
+		dr->func[i].subclass = relations->func[i].subclass;
+		dr->func[i].base_class = relations->func[i].base_class;
+		dr->func[i].subsystem_id = relations->func[i].subsystem_id;
+		dr->func[i].win_slot = relations->func[i].win_slot;
+		dr->func[i].ser = relations->func[i].ser;
+	}
+
+	if (hv_pci_start_relations_work(hbus, dr))
+		kfree(dr);
 }
 
 /**
@@ -3069,7 +3108,7 @@ static int hv_pci_bus_exit(struct hv_device *hdev, bool hibernating)
 		struct pci_packet teardown_packet;
 		u8 buffer[sizeof(struct pci_message)];
 	} pkt;
-	struct pci_bus_relations relations;
+	struct hv_dr_state *dr;
 	struct hv_pci_compl comp_pkt;
 	int ret;
 
@@ -3082,8 +3121,9 @@ static int hv_pci_bus_exit(struct hv_device *hdev, bool hibernating)
 
 	if (!hibernating) {
 		/* Delete any children which might still exist. */
-		memset(&relations, 0, sizeof(relations));
-		hv_pci_devices_present(hbus, &relations);
+		dr = kzalloc(sizeof(*dr), GFP_KERNEL);
+		if (dr && hv_pci_start_relations_work(hbus, dr))
+			kfree(dr);
 	}
 
 	ret = hv_send_resources_released(hdev);
-- 
1.8.3.1

[Patch v5 2/2] PCI: hv: Add support for protocol 1.3 and support PCI_BUS_RELATIONS2

[longli]

From: Long Li <longli@microsoft.com>

Starting with Hyper-V PCI protocol version 1.3, the host VSP can send
PCI_BUS_RELATIONS2 and pass the vNUMA node information for devices on the
bus. The vNUMA node tells which guest NUMA node this device is on based
on guest VM configuration topology and physical device information.

Add code to negotiate v1.3 and process PCI_BUS_RELATIONS2.

Signed-off-by: Long Li <longli@microsoft.com>
Reviewed-by: Michael Kelley <mikelley@microsoft.com>
---
Changes
v2: Changed some spaces to tabs, added put_pcichild() after get_pcichild_wslot(), renamed pci_assign_numa_node() to hv_pci_assign_numa_node()
v4: Fixed spelling
v5: Fixed spelling, rebased to current tree

 drivers/pci/controller/pci-hyperv.c | 109 ++++++++++++++++++++++++++++++++++++
 1 file changed, 109 insertions(+)

diff --git a/drivers/pci/controller/pci-hyperv.c b/drivers/pci/controller/pci-hyperv.c
index dea197f..98d3776 100644
--- a/drivers/pci/controller/pci-hyperv.c
+++ b/drivers/pci/controller/pci-hyperv.c
@@ -63,6 +63,7 @@
 enum pci_protocol_version_t {
 	PCI_PROTOCOL_VERSION_1_1 = PCI_MAKE_VERSION(1, 1),	/* Win10 */
 	PCI_PROTOCOL_VERSION_1_2 = PCI_MAKE_VERSION(1, 2),	/* RS1 */
+	PCI_PROTOCOL_VERSION_1_3 = PCI_MAKE_VERSION(1, 3),	/* Vibranium */
 };
 
 #define CPU_AFFINITY_ALL	-1ULL
@@ -72,6 +73,7 @@ enum pci_protocol_version_t {
  * first.
  */
 static enum pci_protocol_version_t pci_protocol_versions[] = {
+	PCI_PROTOCOL_VERSION_1_3,
 	PCI_PROTOCOL_VERSION_1_2,
 	PCI_PROTOCOL_VERSION_1_1,
 };
@@ -119,6 +121,7 @@ enum pci_message_type {
 	PCI_RESOURCES_ASSIGNED2		= PCI_MESSAGE_BASE + 0x16,
 	PCI_CREATE_INTERRUPT_MESSAGE2	= PCI_MESSAGE_BASE + 0x17,
 	PCI_DELETE_INTERRUPT_MESSAGE2	= PCI_MESSAGE_BASE + 0x18, /* unused */
+	PCI_BUS_RELATIONS2		= PCI_MESSAGE_BASE + 0x19,
 	PCI_MESSAGE_MAXIMUM
 };
 
@@ -164,6 +167,26 @@ struct pci_function_description {
 	u32	ser;	/* serial number */
 } __packed;
 
+enum pci_device_description_flags {
+	HV_PCI_DEVICE_FLAG_NONE			= 0x0,
+	HV_PCI_DEVICE_FLAG_NUMA_AFFINITY	= 0x1,
+};
+
+struct pci_function_description2 {
+	u16	v_id;	/* vendor ID */
+	u16	d_id;	/* device ID */
+	u8	rev;
+	u8	prog_intf;
+	u8	subclass;
+	u8	base_class;
+	u32	subsystem_id;
+	union	win_slot_encoding win_slot;
+	u32	ser;	/* serial number */
+	u32	flags;
+	u16	virtual_numa_node;
+	u16	reserved;
+} __packed;
+
 /**
  * struct hv_msi_desc
  * @vector:		IDT entry
@@ -299,6 +322,12 @@ struct pci_bus_relations {
 	struct pci_function_description func[0];
 } __packed;
 
+struct pci_bus_relations2 {
+	struct pci_incoming_message incoming;
+	u32 device_count;
+	struct pci_function_description2 func[0];
+} __packed;
+
 struct pci_q_res_req_response {
 	struct vmpacket_descriptor hdr;
 	s32 status;			/* negative values are failures */
@@ -1415,6 +1444,7 @@ static void hv_compose_msi_msg(struct irq_data *data, struct msi_msg *msg)
 		break;
 
 	case PCI_PROTOCOL_VERSION_1_2:
+	case PCI_PROTOCOL_VERSION_1_3:
 		size = hv_compose_msi_req_v2(&ctxt.int_pkts.v2,
 					dest,
 					hpdev->desc.win_slot.slot,
@@ -1813,6 +1843,27 @@ static void hv_pci_remove_slots(struct hv_pcibus_device *hbus)
 	}
 }
 
+/*
+ * Set NUMA node for the devices on the bus
+ */
+static void hv_pci_assign_numa_node(struct hv_pcibus_device *hbus)
+{
+	struct pci_dev *dev;
+	struct pci_bus *bus = hbus->pci_bus;
+	struct hv_pci_dev *hv_dev;
+
+	list_for_each_entry(dev, &bus->devices, bus_list) {
+		hv_dev = get_pcichild_wslot(hbus, devfn_to_wslot(dev->devfn));
+		if (!hv_dev)
+			continue;
+
+		if (hv_dev->desc.flags & HV_PCI_DEVICE_FLAG_NUMA_AFFINITY)
+			set_dev_node(&dev->dev, hv_dev->desc.virtual_numa_node);
+
+		put_pcichild(hv_dev);
+	}
+}
+
 /**
  * create_root_hv_pci_bus() - Expose a new root PCI bus
  * @hbus:	Root PCI bus, as understood by this driver
@@ -1835,6 +1886,7 @@ static int create_root_hv_pci_bus(struct hv_pcibus_device *hbus)
 
 	pci_lock_rescan_remove();
 	pci_scan_child_bus(hbus->pci_bus);
+	hv_pci_assign_numa_node(hbus);
 	pci_bus_assign_resources(hbus->pci_bus);
 	hv_pci_assign_slots(hbus);
 	pci_bus_add_devices(hbus->pci_bus);
@@ -2103,6 +2155,7 @@ static void pci_devices_present_work(struct work_struct *work)
 		 */
 		pci_lock_rescan_remove();
 		pci_scan_child_bus(hbus->pci_bus);
+		hv_pci_assign_numa_node(hbus);
 		hv_pci_assign_slots(hbus);
 		pci_unlock_rescan_remove();
 		break;
@@ -2207,6 +2260,46 @@ static void hv_pci_devices_present(struct hv_pcibus_device *hbus,
 }
 
 /**
+ * hv_pci_devices_present2() - Handle list of new children
+ * @hbus:	Root PCI bus, as understood by this driver
+ * @relations:	Packet from host listing children
+ *
+ * This function is the v2 version of hv_pci_devices_present()
+ */
+static void hv_pci_devices_present2(struct hv_pcibus_device *hbus,
+				    struct pci_bus_relations2 *relations)
+{
+	struct hv_dr_state *dr;
+	int i;
+
+	dr = kzalloc(offsetof(struct hv_dr_state, func) +
+		     (sizeof(struct hv_pcidev_description) *
+		      (relations->device_count)), GFP_NOWAIT);
+
+	if (!dr)
+		return;
+
+	dr->device_count = relations->device_count;
+	for (i = 0; i < dr->device_count; i++) {
+		dr->func[i].v_id = relations->func[i].v_id;
+		dr->func[i].d_id = relations->func[i].d_id;
+		dr->func[i].rev = relations->func[i].rev;
+		dr->func[i].prog_intf = relations->func[i].prog_intf;
+		dr->func[i].subclass = relations->func[i].subclass;
+		dr->func[i].base_class = relations->func[i].base_class;
+		dr->func[i].subsystem_id = relations->func[i].subsystem_id;
+		dr->func[i].win_slot = relations->func[i].win_slot;
+		dr->func[i].ser = relations->func[i].ser;
+		dr->func[i].flags = relations->func[i].flags;
+		dr->func[i].virtual_numa_node =
+			relations->func[i].virtual_numa_node;
+	}
+
+	if (hv_pci_start_relations_work(hbus, dr))
+		kfree(dr);
+}
+
+/**
  * hv_eject_device_work() - Asynchronously handles ejection
  * @work:	Work struct embedded in internal device struct
  *
@@ -2319,6 +2412,7 @@ static void hv_pci_onchannelcallback(void *context)
 	struct pci_response *response;
 	struct pci_incoming_message *new_message;
 	struct pci_bus_relations *bus_rel;
+	struct pci_bus_relations2 *bus_rel2;
 	struct pci_dev_inval_block *inval;
 	struct pci_dev_incoming *dev_message;
 	struct hv_pci_dev *hpdev;
@@ -2386,6 +2480,21 @@ static void hv_pci_onchannelcallback(void *context)
 				hv_pci_devices_present(hbus, bus_rel);
 				break;
 
+			case PCI_BUS_RELATIONS2:
+
+				bus_rel2 = (struct pci_bus_relations2 *)buffer;
+				if (bytes_recvd <
+				    offsetof(struct pci_bus_relations2, func) +
+				    (sizeof(struct pci_function_description2) *
+				     (bus_rel2->device_count))) {
+					dev_err(&hbus->hdev->device,
+						"bus relations v2 too small\n");
+					break;
+				}
+
+				hv_pci_devices_present2(hbus, bus_rel2);
+				break;
+
 			case PCI_EJECT:
 
 				dev_message = (struct pci_dev_incoming *)buffer;
-- 
1.8.3.1

Re: [Patch v5 1/2] PCI: hv: Decouple the func definition in hv_dr_state from VSP message

[Lorenzo Pieralisi]

On Tue, Feb 25, 2020 at 09:06:07PM -0800, longli@linuxonhyperv.com wrote:
> From: Long Li <longli@microsoft.com>
> 
> hv_dr_state is used to find present PCI devices on the bus. The structure
> reuses struct pci_function_description from VSP message to describe a
> device.
> 
> To prepare support for pci_function_description v2, decouple this
> dependence in hv_dr_state so it can work with both v1 and v2 VSP messages.
> 
> There is no functionality change.
> 
> Signed-off-by: Long Li <longli@microsoft.com>
> Reviewed-by: Michael Kelley <mikelley@microsoft.com>
> ---
> Changes
> v2: Changed some spaces to tabs, changed failure code to -ENOMEM
> v3: Revised comment for function hv_pci_devices_present(), reformatted patch title
> v4: Fixed spelling
> v5: Rebased to current tree
> 
>  drivers/pci/controller/pci-hyperv.c | 100 +++++++++++++++++++++++++-----------
>  1 file changed, 70 insertions(+), 30 deletions(-)

Applied the series to pci/hv for v5.7.

Thanks,
Lorenzo

> 
> index 15011a3..dea197f 100644
> --- a/drivers/pci/controller/pci-hyperv.c
> +++ b/drivers/pci/controller/pci-hyperv.c
> @@ -505,10 +505,24 @@ struct hv_dr_work {
>  	struct hv_pcibus_device *bus;
>  };
>  
> +struct hv_pcidev_description {
> +	u16	v_id;	/* vendor ID */
> +	u16	d_id;	/* device ID */
> +	u8	rev;
> +	u8	prog_intf;
> +	u8	subclass;
> +	u8	base_class;
> +	u32	subsystem_id;
> +	union	win_slot_encoding win_slot;
> +	u32	ser;	/* serial number */
> +	u32	flags;
> +	u16	virtual_numa_node;
> +};
> +
>  struct hv_dr_state {
>  	struct list_head list_entry;
>  	u32 device_count;
> -	struct pci_function_description func[0];
> +	struct hv_pcidev_description func[0];
>  };
>  
>  enum hv_pcichild_state {
> @@ -525,7 +539,7 @@ struct hv_pci_dev {
>  	refcount_t refs;
>  	enum hv_pcichild_state state;
>  	struct pci_slot *pci_slot;
> -	struct pci_function_description desc;
> +	struct hv_pcidev_description desc;
>  	bool reported_missing;
>  	struct hv_pcibus_device *hbus;
>  	struct work_struct wrk;
> @@ -1877,7 +1891,7 @@ static void q_resource_requirements(void *context, struct pci_response *resp,
>   * Return: Pointer to the new tracking struct
>   */
>  static struct hv_pci_dev *new_pcichild_device(struct hv_pcibus_device *hbus,
> -		struct pci_function_description *desc)
> +		struct hv_pcidev_description *desc)
>  {
>  	struct hv_pci_dev *hpdev;
>  	struct pci_child_message *res_req;
> @@ -1988,7 +2002,7 @@ static void pci_devices_present_work(struct work_struct *work)
>  {
>  	u32 child_no;
>  	bool found;
> -	struct pci_function_description *new_desc;
> +	struct hv_pcidev_description *new_desc;
>  	struct hv_pci_dev *hpdev;
>  	struct hv_pcibus_device *hbus;
>  	struct list_head removed;
> @@ -2107,17 +2121,15 @@ static void pci_devices_present_work(struct work_struct *work)
>  }
>  
>  /**
> - * hv_pci_devices_present() - Handles list of new children
> + * hv_pci_start_relations_work() - Queue work to start device discovery
>   * @hbus:	Root PCI bus, as understood by this driver
> - * @relations:	Packet from host listing children
> + * @dr:		The list of children returned from host
>   *
> - * This function is invoked whenever a new list of devices for
> - * this bus appears.
> + * Return:  0 on success, -errno on failure
>   */
> -static void hv_pci_devices_present(struct hv_pcibus_device *hbus,
> -				   struct pci_bus_relations *relations)
> +static int hv_pci_start_relations_work(struct hv_pcibus_device *hbus,
> +				       struct hv_dr_state *dr)
>  {
> -	struct hv_dr_state *dr;
>  	struct hv_dr_work *dr_wrk;
>  	unsigned long flags;
>  	bool pending_dr;
> @@ -2125,29 +2137,15 @@ static void hv_pci_devices_present(struct hv_pcibus_device *hbus,
>  	if (hbus->state == hv_pcibus_removing) {
>  		dev_info(&hbus->hdev->device,
>  			 "PCI VMBus BUS_RELATIONS: ignored\n");
> -		return;
> +		return -ENOENT;
>  	}
>  
>  	dr_wrk = kzalloc(sizeof(*dr_wrk), GFP_NOWAIT);
>  	if (!dr_wrk)
> -		return;
> -
> -	dr = kzalloc(offsetof(struct hv_dr_state, func) +
> -		     (sizeof(struct pci_function_description) *
> -		      (relations->device_count)), GFP_NOWAIT);
> -	if (!dr)  {
> -		kfree(dr_wrk);
> -		return;
> -	}
> +		return -ENOMEM;
>  
>  	INIT_WORK(&dr_wrk->wrk, pci_devices_present_work);
>  	dr_wrk->bus = hbus;
> -	dr->device_count = relations->device_count;
> -	if (dr->device_count != 0) {
> -		memcpy(dr->func, relations->func,
> -		       sizeof(struct pci_function_description) *
> -		       dr->device_count);
> -	}
>  
>  	spin_lock_irqsave(&hbus->device_list_lock, flags);
>  	/*
> @@ -2165,6 +2163,47 @@ static void hv_pci_devices_present(struct hv_pcibus_device *hbus,
>  		get_hvpcibus(hbus);
>  		queue_work(hbus->wq, &dr_wrk->wrk);
>  	}
> +
> +	return 0;
> +}
> +
> +/**
> + * hv_pci_devices_present() - Handle list of new children
> + * @hbus:      Root PCI bus, as understood by this driver
> + * @relations: Packet from host listing children
> + *
> + * Process a new list of devices on the bus. The list of devices is
> + * discovered by VSP and sent to us via VSP message PCI_BUS_RELATIONS,
> + * whenever a new list of devices for this bus appears.
> + */
> +static void hv_pci_devices_present(struct hv_pcibus_device *hbus,
> +				   struct pci_bus_relations *relations)
> +{
> +	struct hv_dr_state *dr;
> +	int i;
> +
> +	dr = kzalloc(offsetof(struct hv_dr_state, func) +
> +		     (sizeof(struct hv_pcidev_description) *
> +		      (relations->device_count)), GFP_NOWAIT);
> +
> +	if (!dr)
> +		return;
> +
> +	dr->device_count = relations->device_count;
> +	for (i = 0; i < dr->device_count; i++) {
> +		dr->func[i].v_id = relations->func[i].v_id;
> +		dr->func[i].d_id = relations->func[i].d_id;
> +		dr->func[i].rev = relations->func[i].rev;
> +		dr->func[i].prog_intf = relations->func[i].prog_intf;
> +		dr->func[i].subclass = relations->func[i].subclass;
> +		dr->func[i].base_class = relations->func[i].base_class;
> +		dr->func[i].subsystem_id = relations->func[i].subsystem_id;
> +		dr->func[i].win_slot = relations->func[i].win_slot;
> +		dr->func[i].ser = relations->func[i].ser;
> +	}
> +
> +	if (hv_pci_start_relations_work(hbus, dr))
> +		kfree(dr);
>  }
>  
>  /**
> @@ -3069,7 +3108,7 @@ static int hv_pci_bus_exit(struct hv_device *hdev, bool hibernating)
>  		struct pci_packet teardown_packet;
>  		u8 buffer[sizeof(struct pci_message)];
>  	} pkt;
> -	struct pci_bus_relations relations;
> +	struct hv_dr_state *dr;
>  	struct hv_pci_compl comp_pkt;
>  	int ret;
>  
> @@ -3082,8 +3121,9 @@ static int hv_pci_bus_exit(struct hv_device *hdev, bool hibernating)
>  
>  	if (!hibernating) {
>  		/* Delete any children which might still exist. */
> -		memset(&relations, 0, sizeof(relations));
> -		hv_pci_devices_present(hbus, &relations);
> +		dr = kzalloc(sizeof(*dr), GFP_KERNEL);
> +		if (dr && hv_pci_start_relations_work(hbus, dr))
> +			kfree(dr);
>  	}
>  
>  	ret = hv_send_resources_released(hdev);
> -- 
> 1.8.3.1
>