Drivers: hv: util: Fix a bug in the KVP code

Add code to poll the channel since we process only one message
at a time and the host may not interrupt us. Also increase the
receive buffer size since some KVP messages are close to 8K bytes in size.

Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

2 files changed, 15 insertions, 4 deletions

diff --git a/drivers/hv/hv_kvp.c b/drivers/hv/hv_kvp.c
index ea852537307e..521c14625b3a 100644
--- a/drivers/hv/hv_kvp.c
+++ b/drivers/hv/hv_kvp.c
@@ -127,6 +127,17 @@ kvp_work_func(struct work_struct *dummy)
         kvp_respond_to_host(NULL, HV_E_FAIL);
 }
 
+static void poll_channel(struct vmbus_channel *channel)
+{
+        if (channel->target_cpu != smp_processor_id())
+                smp_call_function_single(channel->target_cpu,
+                                         hv_kvp_onchannelcallback,
+                                         channel, true);
+        else
+                hv_kvp_onchannelcallback(channel);
+}
+
+
 static int kvp_handle_handshake(struct hv_kvp_msg *msg)
 {
         int ret = 1;
@@ -155,7 +166,7 @@ static int kvp_handle_handshake(struct hv_kvp_msg *msg)
                 kvp_register(dm_reg_value);
                 kvp_transaction.active = false;
                 if (kvp_transaction.kvp_context)
-                        hv_kvp_onchannelcallback(kvp_transaction.kvp_context);
+                        poll_channel(kvp_transaction.kvp_context);
         }
         return ret;
 }
@@ -568,7 +579,7 @@ response_done:
 
         vmbus_sendpacket(channel, recv_buffer, buf_len, req_id,
                                 VM_PKT_DATA_INBAND, 0);
-
+        poll_channel(channel);
 }
 
 /*
@@ -603,7 +614,7 @@ void hv_kvp_onchannelcallback(void *context)
                 return;
         }
 
-        vmbus_recvpacket(channel, recv_buffer, PAGE_SIZE * 2, &recvlen,
+        vmbus_recvpacket(channel, recv_buffer, PAGE_SIZE * 4, &recvlen,
                          &requestid);
 
         if (recvlen > 0) {
diff --git a/drivers/hv/hv_util.c b/drivers/hv/hv_util.c
index dd761806f0e8..3b9c9ef0deb8 100644
--- a/drivers/hv/hv_util.c
+++ b/drivers/hv/hv_util.c
@@ -319,7 +319,7 @@ static int util_probe(struct hv_device *dev,
                 (struct hv_util_service *)dev_id->driver_data;
         int ret;
 
-        srv->recv_buffer = kmalloc(PAGE_SIZE * 2, GFP_KERNEL);
+        srv->recv_buffer = kmalloc(PAGE_SIZE * 4, GFP_KERNEL);
         if (!srv->recv_buffer)
                 return -ENOMEM;
         if (srv->util_init) {