[Patch 1/2] MdeModulePkg/Ip4Dxe: fix a bug in IP4 driver for IpSec protocol notify.

[Fu Siyuan <siyuan.fu@intel.com>]

The IP driver uses EfiCreateProtocolNotifyEvent() to register notify callback
function for IpSec protocol, but it didn't notice that the callback will always
be executed at least once, even the protocol wasn't in handle database.
As a result, the Ip4IpSecProcessPacket() will still always call LocateProtocol()
even the IpSec protocol is not installed, which will impact the network
performance.

Cc: Ye Ting <ting.ye@intel.com>
Cc: Wu Jiaxin <jiaxin.wu@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Fu Siyuan <siyuan.fu@intel.com>
---
 MdeModulePkg/Universal/Network/Ip4Dxe/Ip4Driver.c | 14 +++++++++++---
 MdeModulePkg/Universal/Network/Ip4Dxe/Ip4Input.c  | 10 ++--------
 2 files changed, 13 insertions(+), 11 deletions(-)

diff --git a/MdeModulePkg/Universal/Network/Ip4Dxe/Ip4Driver.c b/MdeModulePkg/Universal/Network/Ip4Dxe/Ip4Driver.c
index 792db5c..03ba458 100644
--- a/MdeModulePkg/Universal/Network/Ip4Dxe/Ip4Driver.c
+++ b/MdeModulePkg/Universal/Network/Ip4Dxe/Ip4Driver.c
@@ -41,12 +41,20 @@ IpSec2InstalledCallback (
   IN VOID       *Context
   )
 {
+  EFI_STATUS    Status;
   //
-  // Close the event so it does not get called again.
+  // Test if protocol was even found.
+  // Notification function will be called at least once.
   //
-  gBS->CloseEvent (Event);
+  Status = gBS->LocateProtocol (&gEfiIpSec2ProtocolGuid, NULL, &mIpSec);
+  if (Status == EFI_SUCCESS && mIpSec != NULL) {
+    //
+    // Close the event so it does not get called again.
+    //
+    gBS->CloseEvent (Event);
 
-  mIpSec2Installed = TRUE;
+    mIpSec2Installed = TRUE;
+  }
 }
 
 /**
diff --git a/MdeModulePkg/Universal/Network/Ip4Dxe/Ip4Input.c b/MdeModulePkg/Universal/Network/Ip4Dxe/Ip4Input.c
index 09b8f2b..e694323 100644
--- a/MdeModulePkg/Universal/Network/Ip4Dxe/Ip4Input.c
+++ b/MdeModulePkg/Universal/Network/Ip4Dxe/Ip4Input.c
@@ -1,7 +1,7 @@
 /** @file
   IP4 input process.
   
-Copyright (c) 2005 - 2014, Intel Corporation. All rights reserved.<BR>
+Copyright (c) 2005 - 2017, Intel Corporation. All rights reserved.<BR>
 (C) Copyright 2015 Hewlett-Packard Development Company, L.P.<BR>
 
 This program and the accompanying materials
@@ -518,6 +518,7 @@ Ip4IpSecProcessPacket (
   if (!mIpSec2Installed) {
     goto ON_EXIT;
   }
+  ASSERT (mIpSec != NULL);
   
   Packet        = *Netbuf;
   RecycleEvent  = NULL;
@@ -527,13 +528,6 @@ Ip4IpSecProcessPacket (
   FragmentCount = Packet->BlockOpNum;
 
   ZeroMem (&ZeroHead, sizeof (IP4_HEAD));
-  
-  if (mIpSec == NULL) {
-    gBS->LocateProtocol (&gEfiIpSec2ProtocolGuid, NULL, (VOID **) &mIpSec);
-    if (mIpSec == NULL) {
-      goto ON_EXIT;
-    }
-  }
 
   //
   // Check whether the IPsec enable variable is set.
-- 
1.9.5.msysgit.1