Update 2.6.36 to 2.6.36.4wip-dissipation2-jerickso

1 files changed, 26 insertions, 2 deletions

diff --git a/arch/arm/mm/fault-armv.c b/arch/arm/mm/fault-armv.c
index 9b906dec1ca1..56036ff04deb 100644
--- a/arch/arm/mm/fault-armv.c
+++ b/arch/arm/mm/fault-armv.c
@@ -65,6 +65,30 @@ 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)
 {
@@ -89,11 +113,11 @@ static int adjust_pte(struct vm_area_struct *vma, unsigned long address,
          */
         ptl = pte_lockptr(vma->vm_mm, pmd);
         pte = pte_offset_map_nested(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_nested(pte);
 
         return ret;