xen: map foreign pages for shared rings by updating the PTEs directly

[pandora-kernel.git] / mm / vmalloc.c

diff --git a/mm/vmalloc.c b/mm/vmalloc.c
index b669aa6..3231bf3 100644 (file)
--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -2141,23 +2141,30 @@ void  __attribute__((weak)) vmalloc_sync_all(void)
 
 static int f(pte_t *pte, pgtable_t table, unsigned long addr, void *data)
 {
-       /* apply_to_page_range() does all the hard work. */
+       pte_t ***p = data;
+
+       if (p) {
+               *(*p) = pte;
+               (*p)++;
+       }
        return 0;
 }
 
 /**
  *     alloc_vm_area - allocate a range of kernel address space
  *     @size:          size of the area
+ *     @ptes:          returns the PTEs for the address space
  *
  *     Returns:        NULL on failure, vm_struct on success
  *
  *     This function reserves a range of kernel address space, and
  *     allocates pagetables to map that range.  No actual mappings
- *     are created.  If the kernel address space is not shared
- *     between processes, it syncs the pagetable across all
- *     processes.
+ *     are created.
+ *
+ *     If @ptes is non-NULL, pointers to the PTEs (in init_mm)
+ *     allocated for the VM area are returned.
  */
-struct vm_struct *alloc_vm_area(size_t size)
+struct vm_struct *alloc_vm_area(size_t size, pte_t **ptes)
 {
        struct vm_struct *area;
 
@@ -2171,19 +2178,11 @@ struct vm_struct *alloc_vm_area(size_t size)
         * of kernel virtual address space and mapped into init_mm.
         */
        if (apply_to_page_range(&init_mm, (unsigned long)area->addr,
-                               area->size, f, NULL)) {
+                               size, f, ptes ? &ptes : NULL)) {
                free_vm_area(area);
                return NULL;
        }
 
-       /*
-        * If the allocated address space is passed to a hypercall
-        * before being used then we cannot rely on a page fault to
-        * trigger an update of the page tables.  So sync all the page
-        * tables here.
-        */
-       vmalloc_sync_all();
-
        return area;
 }
 EXPORT_SYMBOL_GPL(alloc_vm_area);