badpage: remove vma from page_remove_rmap

Remove page_remove_rmap()'s vma arg, which was only for the Eeek message.
And remove the BUG_ON(page_mapcount(page) == 0) from CONFIG_DEBUG_VM's
page_dup_rmap(): we're trying to be more resilient about that than BUGs.

Signed-off-by: Hugh Dickins <hugh@veritas.com>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Cc: Christoph Lameter <cl@linux-foundation.org>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Rik van Riel <riel@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

include/linux/rmap.h

@@ -69,7 +69,7 @@ void __anon_vma_link(struct vm_area_struct *);
 void page_add_anon_rmap(struct page *, struct vm_area_struct *, unsigned long);
 void page_add_new_anon_rmap(struct page *, struct vm_area_struct *, unsigned long);
 void page_add_file_rmap(struct page *);
-void page_remove_rmap(struct page *, struct vm_area_struct *);
+void page_remove_rmap(struct page *);
 
 #ifdef CONFIG_DEBUG_VM
 void page_dup_rmap(struct page *page, struct vm_area_struct *vma, unsigned long address);

mm/filemap_xip.c

@@ -193,7 +193,7 @@ retry:
 			/* Nuke the page table entry. */
 			flush_cache_page(vma, address, pte_pfn(*pte));
 			pteval = ptep_clear_flush_notify(vma, address, pte);
-			page_remove_rmap(page, vma);
+			page_remove_rmap(page);
 			dec_mm_counter(mm, file_rss);
 			BUG_ON(pte_dirty(pteval));
 			pte_unmap_unlock(pte, ptl);

mm/fremap.c

@@ -37,7 +37,7 @@ static void zap_pte(struct mm_struct *mm, struct vm_area_struct *vma,
 		if (page) {
 			if (pte_dirty(pte))
 				set_page_dirty(page);
-			page_remove_rmap(page, vma);
+			page_remove_rmap(page);
 			page_cache_release(page);
 			update_hiwater_rss(mm);
 			dec_mm_counter(mm, file_rss);

mm/memory.c

@@ -798,7 +798,7 @@ static unsigned long zap_pte_range(struct mmu_gather *tlb,
 					mark_page_accessed(page);
 				file_rss--;
 			}
-			page_remove_rmap(page, vma);
+			page_remove_rmap(page);
 			if (unlikely(page_mapcount(page) < 0))
 				print_bad_pte(vma, addr, ptent, page);
 			tlb_remove_page(tlb, page);
@@ -2023,7 +2023,7 @@ gotten:
 			 * mapcount is visible. So transitively, TLBs to
 			 * old page will be flushed before it can be reused.
 			 */
-			page_remove_rmap(old_page, vma);
+			page_remove_rmap(old_page);
 		}
 
 		/* Free the old page.. */

mm/rmap.c

@@ -707,7 +707,6 @@ void page_add_file_rmap(struct page *page)
  */
 void page_dup_rmap(struct page *page, struct vm_area_struct *vma, unsigned long address)
 {
-	BUG_ON(page_mapcount(page) == 0);
 	if (PageAnon(page))
 		__page_check_anon_rmap(page, vma, address);
 	atomic_inc(&page->_mapcount);
@@ -717,11 +716,10 @@ void page_dup_rmap(struct page *page, struct vm_area_struct *vma, unsigned long
 /**
  * page_remove_rmap - take down pte mapping from a page
  * @page: page to remove mapping from
- * @vma: the vm area in which the mapping is removed
  *
  * The caller needs to hold the pte lock.
  */
-void page_remove_rmap(struct page *page, struct vm_area_struct *vma)
+void page_remove_rmap(struct page *page)
 {
 	if (atomic_add_negative(-1, &page->_mapcount)) {
 		/*
@@ -837,7 +835,7 @@ static int try_to_unmap_one(struct page *page, struct vm_area_struct *vma,
 		dec_mm_counter(mm, file_rss);
 
 
-	page_remove_rmap(page, vma);
+	page_remove_rmap(page);
 	page_cache_release(page);
 
 out_unmap:
@@ -952,7 +950,7 @@ static int try_to_unmap_cluster(unsigned long cursor, unsigned int *mapcount,
 		if (pte_dirty(pteval))
 			set_page_dirty(page);
 
-		page_remove_rmap(page, vma);
+		page_remove_rmap(page);
 		page_cache_release(page);
 		dec_mm_counter(mm, file_rss);
 		(*mapcount)--;