Gitweb:     
http://git.kernel.org/git/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=e0dc0d8f4a327d033bfb63d43f113d5f31d11b3c
Commit:     e0dc0d8f4a327d033bfb63d43f113d5f31d11b3c
Parent:     2ca48ed5cc5935cbd2a6f5d14fecd4ddbbdb4315
Author:     Nick Piggin <[EMAIL PROTECTED]>
AuthorDate: Mon Feb 12 00:51:36 2007 -0800
Committer:  Linus Torvalds <[EMAIL PROTECTED]>
CommitDate: Mon Feb 12 09:48:27 2007 -0800

    [PATCH] add vm_insert_pfn()
    
    Add a vm_insert_pfn helper, so that ->fault handlers can have nopfn
    functionality by installing their own pte and returning NULL.
    
    Signed-off-by: Nick Piggin <[EMAIL PROTECTED]>
    Signed-off-by: Benjamin Herrenschmidt <[EMAIL PROTECTED]>
    Cc: Arnd Bergmann <[EMAIL PROTECTED]>
    Cc: Hugh Dickins <[EMAIL PROTECTED]>
    Cc: Christoph Hellwig <[EMAIL PROTECTED]>
    Signed-off-by: Andrew Morton <[EMAIL PROTECTED]>
    Signed-off-by: Linus Torvalds <[EMAIL PROTECTED]>
---
 include/linux/mm.h |    2 ++
 mm/memory.c        |   45 +++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 47 insertions(+), 0 deletions(-)

diff --git a/include/linux/mm.h b/include/linux/mm.h
index 77a7610..903f3b7 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -1124,6 +1124,8 @@ unsigned long vmalloc_to_pfn(void *addr);
 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);
 
 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 072c113..8b8f0d2 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -1277,6 +1277,51 @@ int vm_insert_page(struct vm_area_struct *vma, unsigned 
long addr, struct page *
 }
 EXPORT_SYMBOL(vm_insert_page);
 
+/**
+ * vm_insert_pfn - insert single pfn into user vma
+ * @vma: user vma to map to
+ * @addr: target user address of this page
+ * @pfn: source kernel pfn
+ *
+ * Similar to vm_inert_page, this allows drivers to insert individual pages
+ * they've allocated into a user vma. Same comments apply.
+ *
+ * This function should only be called from a vm_ops->fault handler, and
+ * in that case the handler should return NULL.
+ */
+int vm_insert_pfn(struct vm_area_struct *vma, unsigned long addr,
+               unsigned long pfn)
+{
+       struct mm_struct *mm = vma->vm_mm;
+       int retval;
+       pte_t *pte, entry;
+       spinlock_t *ptl;
+
+       BUG_ON(!(vma->vm_flags & VM_PFNMAP));
+       BUG_ON(is_cow_mapping(vma->vm_flags));
+
+       retval = -ENOMEM;
+       pte = get_locked_pte(mm, addr, &ptl);
+       if (!pte)
+               goto out;
+       retval = -EBUSY;
+       if (!pte_none(*pte))
+               goto out_unlock;
+
+       /* Ok, finally just insert the thing.. */
+       entry = pfn_pte(pfn, vma->vm_page_prot);
+       set_pte_at(mm, addr, pte, entry);
+       update_mmu_cache(vma, addr, entry);
+
+       retval = 0;
+out_unlock:
+       pte_unmap_unlock(pte, ptl);
+
+out:
+       return retval;
+}
+EXPORT_SYMBOL(vm_insert_pfn);
+
 /*
  * maps a range of physical memory into the requested pages. the old
  * mappings are removed. any references to nonexistent pages results
-
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