[PATCH] Drivers: hv: balloon: add a comment explaining fall through in hv_memory_notifier()

[Vitaly Kuznetsov <vkuznets@redhat.com>]

Coverity scan gives a warning when there is fall through in a switch
without a comment.

Reported-by: Stephen Hemminger <sthemmin@microsoft.com>
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
---
 drivers/hv/hv_balloon.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/hv/hv_balloon.c b/drivers/hv/hv_balloon.c
index 14c3dc4..7e2479f 100644
--- a/drivers/hv/hv_balloon.c
+++ b/drivers/hv/hv_balloon.c
@@ -587,6 +587,12 @@ static int hv_memory_notifier(struct notifier_block *nb, unsigned long val,
 		spin_lock_irqsave(&dm_device.ha_lock, flags);
 		dm_device.num_pages_onlined += mem->nr_pages;
 		spin_unlock_irqrestore(&dm_device.ha_lock, flags);
+		/*
+		 * Fall through - ol_waitevent needs to be completed to unblock
+		 * hv_mem_hot_add() allowing it to process next requests
+		 * regardless of the result of if we were able to online this
+		 * block.
+		 */
 	case MEM_CANCEL_ONLINE:
 		if (dm_device.ha_waiting) {
 			dm_device.ha_waiting = false;
-- 
2.9.3