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

1 files changed, 14 insertions, 19 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);
 }