From 0b2febf38a33d7c40fb7bb4a58c113a1fa33c412 Mon Sep 17 00:00:00 2001
From: Hannes Hering <hering2@de.ibm.com>
Date: Mon, 4 May 2009 11:06:37 -0700
Subject: [PATCH] ehea: fix invalid pointer access

This patch fixes an invalid pointer access in case the receive queue
holds no pointer to the next skb when the queue is empty.

Signed-off-by: Hannes Hering <hering2@de.ibm.com>
Signed-off-by: Jan-Bernd Themann <themann@de.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
 drivers/net/ehea/ehea.h      |  2 +-
 drivers/net/ehea/ehea_main.c | 31 ++++++++++++++++++-------------
 2 files changed, 19 insertions(+), 14 deletions(-)

diff --git a/drivers/net/ehea/ehea.h b/drivers/net/ehea/ehea.h
index 6e317caf429c9..16a41389575ae 100644
--- a/drivers/net/ehea/ehea.h
+++ b/drivers/net/ehea/ehea.h
@@ -40,7 +40,7 @@
 #include <asm/io.h>
 
 #define DRV_NAME	"ehea"
-#define DRV_VERSION	"EHEA_0100"
+#define DRV_VERSION	"EHEA_0101"
 
 /* eHEA capability flags */
 #define DLPAR_PORT_ADD_REM 1
diff --git a/drivers/net/ehea/ehea_main.c b/drivers/net/ehea/ehea_main.c
index 604c844d07693..b22dab9153f67 100644
--- a/drivers/net/ehea/ehea_main.c
+++ b/drivers/net/ehea/ehea_main.c
@@ -545,14 +545,17 @@ static inline struct sk_buff *get_skb_by_index(struct sk_buff **skb_array,
 	x &= (arr_len - 1);
 
 	pref = skb_array[x];
-	prefetchw(pref);
-	prefetchw(pref + EHEA_CACHE_LINE);
-
-	pref = (skb_array[x]->data);
-	prefetch(pref);
-	prefetch(pref + EHEA_CACHE_LINE);
-	prefetch(pref + EHEA_CACHE_LINE * 2);
-	prefetch(pref + EHEA_CACHE_LINE * 3);
+	if (pref) {
+		prefetchw(pref);
+		prefetchw(pref + EHEA_CACHE_LINE);
+
+		pref = (skb_array[x]->data);
+		prefetch(pref);
+		prefetch(pref + EHEA_CACHE_LINE);
+		prefetch(pref + EHEA_CACHE_LINE * 2);
+		prefetch(pref + EHEA_CACHE_LINE * 3);
+	}
+
 	skb = skb_array[skb_index];
 	skb_array[skb_index] = NULL;
 	return skb;
@@ -569,12 +572,14 @@ static inline struct sk_buff *get_skb_by_index_ll(struct sk_buff **skb_array,
 	x &= (arr_len - 1);
 
 	pref = skb_array[x];
-	prefetchw(pref);
-	prefetchw(pref + EHEA_CACHE_LINE);
+	if (pref) {
+		prefetchw(pref);
+		prefetchw(pref + EHEA_CACHE_LINE);
 
-	pref = (skb_array[x]->data);
-	prefetchw(pref);
-	prefetchw(pref + EHEA_CACHE_LINE);
+		pref = (skb_array[x]->data);
+		prefetchw(pref);
+		prefetchw(pref + EHEA_CACHE_LINE);
+	}
 
 	skb = skb_array[wqe_index];
 	skb_array[wqe_index] = NULL;
-- 
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