Merge tag 'hyperv-next-signed-20221009' of git://git.kernel.org/pub/scm/linux/kernel/git/hyperv/linux

Pull hyperv updates from Wei Liu:

 - Remove unnecessary delay while probing for VMBus (Stanislav
   Kinsburskiy)

 - Optimize vmbus_on_event (Saurabh Sengar)

 - Fix a race in Hyper-V DRM driver (Saurabh Sengar)

 - Miscellaneous clean-up patches from various people

* tag 'hyperv-next-signed-20221009' of git://git.kernel.org/pub/scm/linux/kernel/git/hyperv/linux:
  x86/hyperv: Replace kmap() with kmap_local_page()
  drm/hyperv: Add ratelimit on error message
  hyperv: simplify and rename generate_guest_id
  Drivers: hv: vmbus: Split memcpy of flex-array
  scsi: storvsc: remove an extraneous "to" in a comment
  Drivers: hv: vmbus: Don't wait for the ACPI device upon initialization
  Drivers: hv: vmbus: Use PCI_VENDOR_ID_MICROSOFT for better discoverability
  Drivers: hv: vmbus: Fix kernel-doc
  drm/hyperv: Don't overwrite dirt_needed value set by host
  Drivers: hv: vmbus: Optimize vmbus_on_event

2 files changed, 22 insertions, 31 deletions

diff --git a/drivers/hv/connection.c b/drivers/hv/connection.c
index eca7afd366d6..9dc27e5d367a 100644
--- a/drivers/hv/connection.c
+++ b/drivers/hv/connection.c
@@ -431,34 +431,29 @@ struct vmbus_channel *relid2channel(u32 relid)
 void vmbus_on_event(unsigned long data)
 {
 	struct vmbus_channel *channel = (void *) data;
-	unsigned long time_limit = jiffies + 2;
+	void (*callback_fn)(void *context);
 
 	trace_vmbus_on_event(channel);
 
 	hv_debug_delay_test(channel, INTERRUPT_DELAY);
-	do {
-		void (*callback_fn)(void *);
 
-		/* A channel once created is persistent even when
-		 * there is no driver handling the device. An
-		 * unloading driver sets the onchannel_callback to NULL.
-		 */
-		callback_fn = READ_ONCE(channel->onchannel_callback);
-		if (unlikely(callback_fn == NULL))
-			return;
-
-		(*callback_fn)(channel->channel_callback_context);
+	/* A channel once created is persistent even when
+	 * there is no driver handling the device. An
+	 * unloading driver sets the onchannel_callback to NULL.
+	 */
+	callback_fn = READ_ONCE(channel->onchannel_callback);
+	if (unlikely(!callback_fn))
+		return;
 
-		if (channel->callback_mode != HV_CALL_BATCHED)
-			return;
+	(*callback_fn)(channel->channel_callback_context);
 
-		if (likely(hv_end_read(&channel->inbound) == 0))
-			return;
+	if (channel->callback_mode != HV_CALL_BATCHED)
+		return;
 
-		hv_begin_read(&channel->inbound);
-	} while (likely(time_before(jiffies, time_limit)));
+	if (likely(hv_end_read(&channel->inbound) == 0))
+		return;
 
-	/* The time limit (2 jiffies) has been reached */
+	hv_begin_read(&channel->inbound);
 	tasklet_schedule(&channel->callback_event);
 }
 
diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c
index 7b9f3fc3adf7..8b2e413bf19c 100644
--- a/drivers/hv/vmbus_drv.c
+++ b/drivers/hv/vmbus_drv.c
@@ -46,8 +46,6 @@ struct vmbus_dynid {
 
 static struct acpi_device  *hv_acpi_dev;
 
-static struct completion probe_event;
-
 static int hyperv_cpuhp_online;
 
 static void *hv_panic_page;
@@ -1132,7 +1130,8 @@ void vmbus_on_msg_dpc(unsigned long data)
 			return;
 
 		INIT_WORK(&ctx->work, vmbus_onmessage_work);
-		memcpy(&ctx->msg, &msg_copy, sizeof(msg->header) + payload_size);
+		ctx->msg.header = msg_copy.header;
+		memcpy(&ctx->msg.payload, msg_copy.u.payload, payload_size);
 
 		/*
 		 * The host can generate a rescind message while we
@@ -1573,7 +1572,7 @@ err_setup:
 }
 
 /**
- * __vmbus_child_driver_register() - Register a vmbus's driver
+ * __vmbus_driver_register() - Register a vmbus's driver
  * @hv_driver: Pointer to driver structure you want to register
  * @owner: owner module of the drv
  * @mod_name: module name string
@@ -2052,7 +2051,7 @@ struct hv_device *vmbus_device_create(const guid_t *type,
 	child_device_obj->channel = channel;
 	guid_copy(&child_device_obj->dev_type, type);
 	guid_copy(&child_device_obj->dev_instance, instance);
-	child_device_obj->vendor_id = 0x1414; /* MSFT vendor ID */
+	child_device_obj->vendor_id = PCI_VENDOR_ID_MICROSOFT;
 
 	return child_device_obj;
 }
@@ -2468,7 +2467,6 @@ static int vmbus_acpi_add(struct acpi_device *device)
 	ret_val = 0;
 
 acpi_walk_err:
-	complete(&probe_event);
 	if (ret_val)
 		vmbus_acpi_remove(device);
 	return ret_val;
@@ -2647,6 +2645,7 @@ static struct acpi_driver vmbus_acpi_driver = {
 		.remove = vmbus_acpi_remove,
 	},
 	.drv.pm = &vmbus_bus_pm,
+	.drv.probe_type = PROBE_FORCE_SYNCHRONOUS,
 };
 
 static void hv_kexec_handler(void)
@@ -2719,7 +2718,7 @@ static struct syscore_ops hv_synic_syscore_ops = {
 
 static int __init hv_acpi_init(void)
 {
-	int ret, t;
+	int ret;
 
 	if (!hv_is_hyperv_initialized())
 		return -ENODEV;
@@ -2727,8 +2726,6 @@ static int __init hv_acpi_init(void)
 	if (hv_root_partition)
 		return 0;
 
-	init_completion(&probe_event);
-
 	/*
 	 * Get ACPI resources first.
 	 */
@@ -2737,9 +2734,8 @@ static int __init hv_acpi_init(void)
 	if (ret)
 		return ret;
 
-	t = wait_for_completion_timeout(&probe_event, 5*HZ);
-	if (t == 0) {
-		ret = -ETIMEDOUT;
+	if (!hv_acpi_dev) {
+		ret = -ENODEV;
 		goto cleanup;
 	}