--
woof.
>From c6fc21397e37481696723115cb1680f42661be48 Mon Sep 17 00:00:00 2001
From: Izik Eidus <[EMAIL PROTECTED]>
Date: Mon, 21 Jan 2008 17:04:45 +0200
Subject: [PATCH] memory.c: add new exported function replace_page()
replace_page() - replace the pte mapping related to vm area between two pages
(from oldpage to newpage)
Signed-off-by: Izik Eidus <[EMAIL PROTECTED]>
---
include/linux/mm.h | 5 +++-
mm/memory.c | 60 ++++++++++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 64 insertions(+), 1 deletions(-)
diff --git a/include/linux/mm.h b/include/linux/mm.h
index 1b7b95c..a311c25 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -1094,7 +1094,10 @@ int remap_pfn_range(struct vm_area_struct *, unsigned long addr,
unsigned long pfn, unsigned long size, pgprot_t);
int vm_insert_page(struct vm_area_struct *, unsigned long addr, struct page *);
int vm_insert_pfn(struct vm_area_struct *vma, unsigned long addr,
- unsigned long pfn);
+ unsigned long pfn);
+
+int replace_page(struct vm_area_struct *vma, struct page *oldpage,
+ struct page *newpage, pgprot_t prot);
struct page *follow_page(struct vm_area_struct *, unsigned long address,
unsigned int foll_flags);
diff --git a/mm/memory.c b/mm/memory.c
index 4bf0b6d..d8cb36b 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -2360,6 +2360,66 @@ static int do_linear_fault(struct mm_struct *mm, struct vm_area_struct *vma,
return __do_fault(mm, vma, address, pmd, pgoff, flags, orig_pte);
}
+/**
+ * replace_page - replace the pte mapping related to vm area between two pages
+ * (from oldpage to newpage)
+ */
+int replace_page(struct vm_area_struct *vma, struct page *oldpage,
+ struct page *newpage, pgprot_t prot)
+{
+ struct mm_struct *mm = vma->vm_mm;
+ pgd_t *pgd;
+ pud_t *pud;
+ pmd_t *pmd;
+ pte_t *ptep;
+ spinlock_t *ptl;
+ unsigned long addr;
+ int ret;
+
+ BUG_ON(!PageLocked(oldpage));
+
+ ret = -EFAULT;
+ addr = page_address_in_vma(oldpage, vma);
+ if (addr == -EFAULT)
+ goto out;
+
+ pgd = pgd_offset(mm, addr);
+ if (!pgd_present(*pgd))
+ goto out;
+
+ pud = pud_offset(pgd, addr);
+ if (!pud_present(*pud))
+ goto out;
+
+ pmd = pmd_offset(pud, addr);
+ if (!pmd_present(*pmd))
+ goto out;
+
+ ptep = pte_offset_map_lock(mm, pmd, addr, &ptl);
+ if (!ptep)
+ goto out;
+
+ ret = 0;
+ get_page(newpage);
+ page_add_file_rmap(newpage);
+
+ flush_cache_page(vma, addr, pte_pfn(*ptep));
+ ptep_clear_flush(vma, addr, ptep);
+ set_pte_at(mm, addr, ptep, mk_pte(newpage, prot));
+
+ page_remove_rmap(oldpage, vma);
+ if (PageAnon(oldpage)) {
+ dec_mm_counter(mm, anon_rss);
+ inc_mm_counter(mm, file_rss);
+ }
+ put_page(oldpage);
+
+ pte_unmap_unlock(ptep, ptl);
+out:
+ return ret;
+}
+EXPORT_SYMBOL_GPL(replace_page);
+
/*
* do_no_pfn() tries to create a new page mapping for a page without
--
1.5.3.6
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