Commit 209b450c authored by Andrew Morton's avatar Andrew Morton Committed by Linus Torvalds

[PATCH] mremap: copy_one_pte cleanup

From: Hugh Dickins <hugh@veritas.com>

Clean up mremap move's copy_one_pte:

- get_one_pte_map_nested already weeded out the pte_none case,
  now don't even call copy_one_pte if it has nothing to do.

- check pfn_valid before passing page to page_remove_rmap.
parent 424e44d1
......@@ -79,31 +79,21 @@ static inline pte_t *alloc_one_pte_map(struct mm_struct *mm, unsigned long addr)
return pte;
}
static int
static void
copy_one_pte(struct vm_area_struct *vma, unsigned long old_addr,
pte_t *src, pte_t *dst, struct pte_chain **pte_chainp)
{
int error = 0;
pte_t pte;
struct page *page = NULL;
if (pte_present(*src))
page = pte_page(*src);
pte_t pte = ptep_clear_flush(vma, old_addr, src);
set_pte(dst, pte);
if (!pte_none(*src)) {
if (page)
if (pte_present(pte)) {
unsigned long pfn = pte_pfn(pte);
if (pfn_valid(pfn)) {
struct page *page = pfn_to_page(pfn);
page_remove_rmap(page, src);
pte = ptep_clear_flush(vma, old_addr, src);
if (!dst) {
/* No dest? We must put it back. */
dst = src;
error++;
}
set_pte(dst, pte);
if (page)
*pte_chainp = page_add_rmap(page, dst, *pte_chainp);
}
return error;
}
}
static int
......@@ -140,8 +130,11 @@ move_one_page(struct vm_area_struct *vma, unsigned long old_addr,
* page_table_lock, we should re-check the src entry...
*/
if (src) {
error = copy_one_pte(vma, old_addr, src,
if (dst)
copy_one_pte(vma, old_addr, src,
dst, &pte_chain);
else
error = -ENOMEM;
pte_unmap_nested(src);
}
pte_unmap(dst);
......
Markdown is supported
0%
or
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment