2 files changed, 13 insertions, 17 deletions

diff --git a/arch/x86/include/asm/xen/page.h b/arch/x86/include/asm/xen/page.h
index 93971e841dd5..472b9b783019 100644
--- a/arch/x86/include/asm/xen/page.h
+++ b/arch/x86/include/asm/xen/page.h
@@ -51,7 +51,8 @@ extern unsigned long set_phys_range_identity(unsigned long pfn_s,
 
 extern int m2p_add_override(unsigned long mfn, struct page *page,
                             struct gnttab_map_grant_ref *kmap_op);
-extern int m2p_remove_override(struct page *page, bool clear_pte);
+extern int m2p_remove_override(struct page *page,
+                                struct gnttab_map_grant_ref *kmap_op);
 extern struct page *m2p_find_override(unsigned long mfn);
 extern unsigned long m2p_find_override_pfn(unsigned long mfn, unsigned long pfn);
 
diff --git a/arch/x86/xen/p2m.c b/arch/x86/xen/p2m.c
index 76ba0e97e530..72213da605f5 100644
--- a/arch/x86/xen/p2m.c
+++ b/arch/x86/xen/p2m.c
@@ -828,9 +828,6 @@ int m2p_add_override(unsigned long mfn, struct page *page,
 
                         xen_mc_issue(PARAVIRT_LAZY_MMU);
                 }
-                /* let's use dev_bus_addr to record the old mfn instead */
-                kmap_op->dev_bus_addr = page->index;
-                page->index = (unsigned long) kmap_op;
         }
         spin_lock_irqsave(&m2p_override_lock, flags);
         list_add(&page->lru,  &m2p_overrides[mfn_hash(mfn)]);
@@ -857,7 +854,8 @@ int m2p_add_override(unsigned long mfn, struct page *page,
         return 0;
 }
 EXPORT_SYMBOL_GPL(m2p_add_override);
-int m2p_remove_override(struct page *page, bool clear_pte)
+int m2p_remove_override(struct page *page,
+                struct gnttab_map_grant_ref *kmap_op)
 {
         unsigned long flags;
         unsigned long mfn;
@@ -887,10 +885,8 @@ int m2p_remove_override(struct page *page, bool clear_pte)
         WARN_ON(!PagePrivate(page));
         ClearPagePrivate(page);
 
-        if (clear_pte) {
-                struct gnttab_map_grant_ref *map_op =
-                        (struct gnttab_map_grant_ref *) page->index;
-                set_phys_to_machine(pfn, map_op->dev_bus_addr);
+        set_phys_to_machine(pfn, page->index);
+        if (kmap_op != NULL) {
                 if (!PageHighMem(page)) {
                         struct multicall_space mcs;
                         struct gnttab_unmap_grant_ref *unmap_op;
@@ -902,13 +898,13 @@ int m2p_remove_override(struct page *page, bool clear_pte)
                          * issued. In this case handle is going to -1 because
                          * it hasn't been modified yet.
                          */
-                        if (map_op->handle == -1)
+                        if (kmap_op->handle == -1)
                                 xen_mc_flush();
                         /*
-                         * Now if map_op->handle is negative it means that the
+                         * Now if kmap_op->handle is negative it means that the
                          * hypercall actually returned an error.
                          */
-                        if (map_op->handle == GNTST_general_error) {
+                        if (kmap_op->handle == GNTST_general_error) {
                                 printk(KERN_WARNING "m2p_remove_override: "
                                                 "pfn %lx mfn %lx, failed to modify kernel mappings",
                                                 pfn, mfn);
@@ -918,8 +914,8 @@ int m2p_remove_override(struct page *page, bool clear_pte)
                         mcs = xen_mc_entry(
                                         sizeof(struct gnttab_unmap_grant_ref));
                         unmap_op = mcs.args;
-                        unmap_op->host_addr = map_op->host_addr;
-                        unmap_op->handle = map_op->handle;
+                        unmap_op->host_addr = kmap_op->host_addr;
+                        unmap_op->handle = kmap_op->handle;
                         unmap_op->dev_bus_addr = 0;
 
                         MULTI_grant_table_op(mcs.mc,
@@ -930,10 +926,9 @@ int m2p_remove_override(struct page *page, bool clear_pte)
                         set_pte_at(&init_mm, address, ptep,
                                         pfn_pte(pfn, PAGE_KERNEL));
                         __flush_tlb_single(address);
-                        map_op->host_addr = 0;
+                        kmap_op->host_addr = 0;
                 }
-        } else
-                set_phys_to_machine(pfn, page->index);
+        }
 
         /* p2m(m2p(mfn)) == FOREIGN_FRAME(mfn): the mfn is already present
          * somewhere in this domain, even before being added to the