Re: forget_pte()

[William Lee Irwin III <wli@holomorphy.com>]

On Sat, Jun 01, 2002 at 09:40:02AM -0700, William Lee Irwin III wrote:
...

patch updated to incorporate rusty's suggestion:


===== mm/memory.c 1.70 vs edited =====
--- 1.70/mm/memory.c	Fri May 31 18:18:07 2002
+++ edited/mm/memory.c	Sun Jun  2 22:37:17 2002
@@ -310,17 +310,6 @@
 	return -ENOMEM;
 }
 
-/*
- * Return indicates whether a page was freed so caller can adjust rss
- */
-static inline void forget_pte(pte_t page)
-{
-	if (!pte_none(page)) {
-		printk("forget_pte: old mapping existed!\n");
-		BUG();
-	}
-}
-
 static void zap_pte_range(mmu_gather_t *tlb, pmd_t * pmd, unsigned long address, unsigned long size)
 {
 	unsigned long offset;
@@ -779,7 +768,8 @@
 		pte_t zero_pte = pte_wrprotect(mk_pte(ZERO_PAGE(address), prot));
 		pte_t oldpage = ptep_get_and_clear(pte);
 		set_pte(pte, zero_pte);
-		forget_pte(oldpage);
+		/* PTE's must be unmapped */
+		BUG_ON(!pte_none(oldpage));
 		address += PAGE_SIZE;
 		pte++;
 	} while (address && (address < end));
@@ -857,7 +847,8 @@
 
 		if (!pfn_valid(pfn) || PageReserved(pfn_to_page(pfn)))
  			set_pte(pte, pfn_pte(pfn, prot));
-		forget_pte(oldpage);
+		/* PTE's must be unmapped */
+		BUG_ON(!pte_none(oldpage));
 		address += PAGE_SIZE;
 		pfn++;
 		pte++;