From 52179dc9c4335f0a7e9841de8a39f783e289db21 Mon Sep 17 00:00:00 2001
From: Mika Westerberg <mika.westerberg@iki.fi>
Date: Thu, 28 Oct 2010 11:45:22 +0100
Subject: [PATCH] --- yaml --- r: 221025 b: refs/heads/master c:
 4e54d93d3c9846ba1c2644ad06463dafa690d1b7 h: refs/heads/master i:   221023:
 0bf943857cd1c7187c11c169036463af18318cff v: v3

---
 [refs]                         |  2 +-
 trunk/arch/arm/mm/fault-armv.c | 28 ++++++++++++++++++++++++++--
 2 files changed, 27 insertions(+), 3 deletions(-)

diff --git a/[refs] b/[refs]
index f40f5bafb998..74386605b656 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 4e929d2bcf13eeaa9636448c55690b383a910391
+refs/heads/master: 4e54d93d3c9846ba1c2644ad06463dafa690d1b7
diff --git a/trunk/arch/arm/mm/fault-armv.c b/trunk/arch/arm/mm/fault-armv.c
index c493d7244d3d..83e59f870426 100644
--- a/trunk/arch/arm/mm/fault-armv.c
+++ b/trunk/arch/arm/mm/fault-armv.c
@@ -66,6 +66,30 @@ static int do_adjust_pte(struct vm_area_struct *vma, unsigned long address,
 	return ret;
 }
 
+#if USE_SPLIT_PTLOCKS
+/*
+ * If we are using split PTE locks, then we need to take the page
+ * lock here.  Otherwise we are using shared mm->page_table_lock
+ * which is already locked, thus cannot take it.
+ */
+static inline void do_pte_lock(spinlock_t *ptl)
+{
+	/*
+	 * Use nested version here to indicate that we are already
+	 * holding one similar spinlock.
+	 */
+	spin_lock_nested(ptl, SINGLE_DEPTH_NESTING);
+}
+
+static inline void do_pte_unlock(spinlock_t *ptl)
+{
+	spin_unlock(ptl);
+}
+#else /* !USE_SPLIT_PTLOCKS */
+static inline void do_pte_lock(spinlock_t *ptl) {}
+static inline void do_pte_unlock(spinlock_t *ptl) {}
+#endif /* USE_SPLIT_PTLOCKS */
+
 static int adjust_pte(struct vm_area_struct *vma, unsigned long address,
 	unsigned long pfn)
 {
@@ -90,11 +114,11 @@ static int adjust_pte(struct vm_area_struct *vma, unsigned long address,
 	 */
 	ptl = pte_lockptr(vma->vm_mm, pmd);
 	pte = pte_offset_map(pmd, address);
-	spin_lock(ptl);
+	do_pte_lock(ptl);
 
 	ret = do_adjust_pte(vma, address, pfn, pte);
 
-	spin_unlock(ptl);
+	do_pte_unlock(ptl);
 	pte_unmap(pte);
 
 	return ret;