1 files changed, 26 insertions, 2 deletions

diff --git a/drivers/hv/channel.c b/drivers/hv/channel.c
index fddd3b5e59a9..54da66dc7d16 100644
--- a/drivers/hv/channel.c
+++ b/drivers/hv/channel.c
@@ -611,7 +611,19 @@ int vmbus_sendpacket_ctl(struct vmbus_channel *channel, void *buffer,
 
         ret = hv_ringbuffer_write(&channel->outbound, bufferlist, 3, &signal);
 
-        if ((ret == 0) && kick_q && signal)
+        /*
+         * Signalling the host is conditional on many factors:
+         * 1. The ring state changed from being empty to non-empty.
+         *    This is tracked by the variable "signal".
+         * 2. The variable kick_q tracks if more data will be placed
+         *    on the ring. We will not signal if more data is
+         *    to be placed.
+         *
+         * If we cannot write to the ring-buffer; signal the host
+         * even if we may not have written anything. This is a rare
+         * enough condition that it should not matter.
+         */
+        if (((ret == 0) && kick_q && signal) || (ret))
                 vmbus_setevent(channel);
 
         return ret;
@@ -702,7 +714,19 @@ int vmbus_sendpacket_pagebuffer_ctl(struct vmbus_channel *channel,
 
         ret = hv_ringbuffer_write(&channel->outbound, bufferlist, 3, &signal);
 
-        if ((ret == 0) && kick_q && signal)
+        /*
+         * Signalling the host is conditional on many factors:
+         * 1. The ring state changed from being empty to non-empty.
+         *    This is tracked by the variable "signal".
+         * 2. The variable kick_q tracks if more data will be placed
+         *    on the ring. We will not signal if more data is
+         *    to be placed.
+         *
+         * If we cannot write to the ring-buffer; signal the host
+         * even if we may not have written anything. This is a rare
+         * enough condition that it should not matter.
+         */
+        if (((ret == 0) && kick_q && signal) || (ret))
                 vmbus_setevent(channel);
 
         return ret;