xen/arm: Use p2m entry with lock protection

A new local variable is introduced for accessing p2m entry with lock
protection.

Signed-off-by: Hillf Danton <hdanton@sina.com>
Signed-off-by: Stefano Stabellini <sstabellini@kernel.org>
Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>

diff --git a/arch/arm/xen/p2m.c b/arch/arm/xen/p2m.c
index d3f632c..da2a704 100644 (file)
--- a/arch/arm/xen/p2m.c
+++ b/arch/arm/xen/p2m.c
@@ -70,8 +70,9 @@ unsigned long __pfn_to_mfn(unsigned long pfn)
                entry = rb_entry(n, struct xen_p2m_entry, rbnode_phys);
                if (entry->pfn <= pfn &&
                                entry->pfn + entry->nr_pages > pfn) {
+                       unsigned long mfn = entry->mfn + (pfn - entry->pfn);
                        read_unlock_irqrestore(&p2m_lock, irqflags);
-                       return entry->mfn + (pfn - entry->pfn);
+                       return mfn;
                }
                if (pfn < entry->pfn)
                        n = n->rb_left;