Drivers: hv: vmbus: add a hvsock flag in struct hv_driver

BugLink: http://bugs.launchpad.net/bugs/1541585

Only the coming hv_sock driver has a "true" value for this flag.

We treat the hvsock offers/channels as special VMBus devices.
Since the hv_sock driver handles all the hvsock offers/channels, we need to
tweak vmbus_match() for hv_sock driver, so we introduce this flag.
Signed-off-by: Dexuan Cui <decui@microsoft.com>
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
(cherry picked from commit 8981da32)
Signed-off-by: Tim Gardner <tim.gardner@canonical.com>

drivers/hv/vmbus_drv.c

@@ -581,6 +581,10 @@ static int vmbus_match(struct device *device, struct device_driver *driver)
 	struct hv_driver *drv = drv_to_hv_drv(driver);
 	struct hv_device *hv_dev = device_to_hv_device(device);
 
+	/* The hv_sock driver handles all hv_sock offers. */
+	if (is_hvsock_channel(hv_dev->channel))
+		return drv->hvsock;
+
 	if (hv_vmbus_get_id(drv->id_table, &hv_dev->dev_type))
 		return 1;
 

include/linux/hyperv.h

@@ -990,6 +990,20 @@ extern void vmbus_ontimer(unsigned long data);
 struct hv_driver {
 	const char *name;
 
+	/*
+	 * A hvsock offer, which has a VMBUS_CHANNEL_TLNPI_PROVIDER_OFFER
+	 * channel flag, actually doesn't mean a synthetic device because the
+	 * offer's if_type/if_instance can change for every new hvsock
+	 * connection.
+	 *
+	 * However, to facilitate the notification of new-offer/rescind-offer
+	 * from vmbus driver to hvsock driver, we can handle hvsock offer as
+	 * a special vmbus device, and hence we need the below flag to
+	 * indicate if the driver is the hvsock driver or not: we need to
+	 * specially treat the hvosck offer & driver in vmbus_match().
+	 */
+	bool hvsock;
+
 	/* the device type supported by this driver */
 	uuid_le dev_type;
 	const struct hv_vmbus_device_id *id_table;