From 99db5fe5f3e301a37bd3576a02f15f96ba6e0eb9 Mon Sep 17 00:00:00 2001
From: Eduardo Habkost <ehabkost@redhat.com>
Date: Tue, 3 Mar 2009 16:44:08 -0300
Subject: [PATCH 2/3] kvm: external module: backward compatibility for compound_head()

(cherry picked from commit 5ccf827b6347c04db6b779365b249a17fef62675)

[ehabkost: solved conflicts manually on cherry-picking]

Signed-off-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
RH-Upstream-status: applied(kvm/master)
Bugzilla: 488727
Acked-by: Eduardo Habkost <ehabkost@redhat.com>
Acked-by: Andrea Arcangeli <aarcange@redhat.com>
---
 kernel/external-module-compat-comm.h |   13 +++++++++++++
 1 files changed, 13 insertions(+), 0 deletions(-)

diff --git a/kernel/external-module-compat-comm.h b/kernel/external-module-compat-comm.h
index b86ed61..c1fc866 100644
--- a/kernel/external-module-compat-comm.h
+++ b/kernel/external-module-compat-comm.h
@@ -738,3 +738,16 @@ static inline void cpumask_clear_cpu(int cpu, cpumask_var_t mask)
 #if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,28)
 #define marker_synchronize_unregister() synchronize_sched()
 #endif
+
+/* compound_head() was introduced in 2.6.22 */
+
+#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,22)
+
+static inline struct page *compound_head(struct page *page)
+{
+	if (PageCompound(page))
+		page = (struct page *)page_private(page);
+	return page;
+}
+
+#endif
-- 
1.6.1