Move vmalloc_to_page() to mm/vmalloc.

We already have page table manipulation for vmalloc in vmalloc.c. Move the
vmalloc_to_page() function there as well.

Move the definitions for vmalloc related functions in mm.h to a newly created
section.  A better place would be vmalloc.h but mm.h is basic and may depend
on these functions.  An alternative would be to include vmalloc.h in mm.h
(like done for vmstat.h).

Signed-off-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 38 insertions, 0 deletions

diff --git a/mm/vmalloc.c b/mm/vmalloc.c
index af77e171e339..e4c59a30835b 100644
--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -166,6 +166,44 @@ int map_vm_area(struct vm_struct *area, pgprot_t prot, struct page ***pages)
 }
 EXPORT_SYMBOL_GPL(map_vm_area);
 
+/*
+ * Map a vmalloc()-space virtual address to the physical page.
+ */
+struct page *vmalloc_to_page(void *vmalloc_addr)
+{
+        unsigned long addr = (unsigned long) vmalloc_addr;
+        struct page *page = NULL;
+        pgd_t *pgd = pgd_offset_k(addr);
+        pud_t *pud;
+        pmd_t *pmd;
+        pte_t *ptep, pte;
+
+        if (!pgd_none(*pgd)) {
+                pud = pud_offset(pgd, addr);
+                if (!pud_none(*pud)) {
+                        pmd = pmd_offset(pud, addr);
+                        if (!pmd_none(*pmd)) {
+                                ptep = pte_offset_map(pmd, addr);
+                                pte = *ptep;
+                                if (pte_present(pte))
+                                        page = pte_page(pte);
+                                pte_unmap(ptep);
+                        }
+                }
+        }
+        return page;
+}
+EXPORT_SYMBOL(vmalloc_to_page);
+
+/*
+ * Map a vmalloc()-space virtual address to the physical page frame number.
+ */
+unsigned long vmalloc_to_pfn(void *vmalloc_addr)
+{
+        return page_to_pfn(vmalloc_to_page(vmalloc_addr));
+}
+EXPORT_SYMBOL(vmalloc_to_pfn);
+
 static struct vm_struct *__get_vm_area_node(unsigned long size, unsigned long flags,
                                             unsigned long start, unsigned long end,
                                             int node, gfp_t gfp_mask)