[Xen-devel] [PATCH 3/3] [RFC] User-space grant table device - changes to PV linux

[Derek Murray <Derek.Murray@xxxxxxxxxxxx>]

Changes to the paravirtualised version of Linux to add a hook before  
the page table is cleared, for use with the grant-table device.
Signed-off-by: Derek Murray <Derek.Murray@xxxxxxxxxxxx>
---
diff -r 809f36b1b685 linux-2.6-xen-sparse/include/linux/mm.h
--- a/linux-2.6-xen-sparse/include/linux/mm.h	Thu Mar 15 10:43:13  
2007 +0000
+++ b/linux-2.6-xen-sparse/include/linux/mm.h	Thu Mar 15 17:46:06  
2007 +0000
@@ -205,6 +205,7 @@ struct vm_operations_struct {
        /* notification that a previously read-only page is about to become
         * writable, if an error is returned it will cause a SIGBUS */
        int (*page_mkwrite)(struct vm_area_struct *vma, struct page *page);
+       void (*unmap_page_range)(struct vm_area_struct *vma);
#ifdef CONFIG_NUMA
        int (*set_policy)(struct vm_area_struct *vma, struct mempolicy *new);
        struct mempolicy *(*get_policy)(struct vm_area_struct *vma,
diff -r 809f36b1b685 linux-2.6-xen-sparse/mm/memory.c
--- a/linux-2.6-xen-sparse/mm/memory.c  Thu Mar 15 10:43:13 2007 +0000
+++ b/linux-2.6-xen-sparse/mm/memory.c  Thu Mar 15 17:46:06 2007 +0000
@@ -755,6 +755,15 @@ static unsigned long unmap_page_range(st
                details = NULL;
        BUG_ON(addr >= end);
+
+       /*
+        * If specified, call the following hook to perform any unmapping
+        * operations before the PTEs are destroyed.
+        */
+       if (vma->vm_ops)
+               if (unlikely(vma->vm_ops->unmap_page_range))
+                       vma->vm_ops->unmap_page_range(vma);
+
        tlb_start_vma(tlb, vma);
        pgd = pgd_offset(vma->vm_mm, addr);
        do {


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