Convert clear_page_range pagetable walkers to loops using p?d_addr_end.
These are exceptional in that some out-of-tree memory layouts might pass
end 0, so the macros need to handle that (though previous code did not).

The naming here was out of step: now we usually pass pmd_t *pmd down to
action_on_pte_range, not action_on_pmd_range, etc: made like the others.

Signed-off-by: Hugh Dickins <[EMAIL PROTECTED]>
---

 mm/memory.c |   98 ++++++++++++++++++++++++++++--------------------------------
 1 files changed, 46 insertions(+), 52 deletions(-)

--- ptwalk11/mm/memory.c        2005-03-09 01:38:54.000000000 +0000
+++ ptwalk12/mm/memory.c        2005-03-09 01:39:06.000000000 +0000
@@ -110,15 +110,14 @@ void pmd_clear_bad(pmd_t *pmd)
  * Note: this doesn't free the actual pages themselves. That
  * has been handled earlier when unmapping all the memory regions.
  */
-static inline void clear_pmd_range(struct mmu_gather *tlb, pmd_t *pmd, 
unsigned long start, unsigned long end)
+static inline void clear_pte_range(struct mmu_gather *tlb, pmd_t *pmd,
+                               unsigned long addr, unsigned long end)
 {
-       struct page *page;
-
        if (pmd_none_or_clear_bad(pmd))
                return;
-       if (!((start | end) & ~PMD_MASK)) {
-               /* Only clear full, aligned ranges */
-               page = pmd_page(*pmd);
+       if (!((addr | end) & ~PMD_MASK)) {
+               /* Only free fully aligned ranges */
+               struct page *page = pmd_page(*pmd);
                pmd_clear(pmd);
                dec_page_state(nr_page_table_pages);
                tlb->mm->nr_ptes--;
@@ -126,77 +125,72 @@ static inline void clear_pmd_range(struc
        }
 }
 
-static inline void clear_pud_range(struct mmu_gather *tlb, pud_t *pud, 
unsigned long start, unsigned long end)
+static inline void clear_pmd_range(struct mmu_gather *tlb, pud_t *pud,
+                               unsigned long addr, unsigned long end)
 {
-       unsigned long addr = start, next;
-       pmd_t *pmd, *__pmd;
+       pmd_t *pmd;
+       unsigned long next;
+       pmd_t *empty_pmd = NULL;
 
        if (pud_none_or_clear_bad(pud))
                return;
-       pmd = __pmd = pmd_offset(pud, start);
+       pmd = pmd_offset(pud, addr);
+
+       /* Only free fully aligned ranges */
+       if (!((addr | end) & ~PUD_MASK))
+               empty_pmd = pmd;
        do {
-               next = (addr + PMD_SIZE) & PMD_MASK;
-               if (next > end || next <= addr)
-                       next = end;
-               
-               clear_pmd_range(tlb, pmd, addr, next);
-               pmd++;
-               addr = next;
-       } while (addr && (addr < end));
+               next = pmd_addr_end(addr, end);
+               clear_pte_range(tlb, pmd, addr, next);
+       } while (pmd++, addr = next, addr != end);
 
-       if (!((start | end) & ~PUD_MASK)) {
-               /* Only clear full, aligned ranges */
+       if (empty_pmd) {
                pud_clear(pud);
-               pmd_free_tlb(tlb, __pmd);
+               pmd_free_tlb(tlb, empty_pmd);
        }
 }
 
-
-static inline void clear_pgd_range(struct mmu_gather *tlb, pgd_t *pgd, 
unsigned long start, unsigned long end)
+static inline void clear_pud_range(struct mmu_gather *tlb, pgd_t *pgd,
+                               unsigned long addr, unsigned long end)
 {
-       unsigned long addr = start, next;
-       pud_t *pud, *__pud;
+       pud_t *pud;
+       unsigned long next;
+       pud_t *empty_pud = NULL;
 
        if (pgd_none_or_clear_bad(pgd))
                return;
-       pud = __pud = pud_offset(pgd, start);
+       pud = pud_offset(pgd, addr);
+
+       /* Only free fully aligned ranges */
+       if (!((addr | end) & ~PGDIR_MASK))
+               empty_pud = pud;
        do {
-               next = (addr + PUD_SIZE) & PUD_MASK;
-               if (next > end || next <= addr)
-                       next = end;
-               
-               clear_pud_range(tlb, pud, addr, next);
-               pud++;
-               addr = next;
-       } while (addr && (addr < end));
+               next = pud_addr_end(addr, end);
+               clear_pmd_range(tlb, pud, addr, next);
+       } while (pud++, addr = next, addr != end);
 
-       if (!((start | end) & ~PGDIR_MASK)) {
-               /* Only clear full, aligned ranges */
+       if (empty_pud) {
                pgd_clear(pgd);
-               pud_free_tlb(tlb, __pud);
+               pud_free_tlb(tlb, empty_pud);
        }
 }
 
 /*
  * This function clears user-level page tables of a process.
- *
+ * Unlike other pagetable walks, some memory layouts might give end 0.
  * Must be called with pagetable lock held.
  */
-void clear_page_range(struct mmu_gather *tlb, unsigned long start, unsigned 
long end)
+void clear_page_range(struct mmu_gather *tlb,
+                               unsigned long addr, unsigned long end)
 {
-       unsigned long addr = start, next;
-       pgd_t * pgd = pgd_offset(tlb->mm, start);
-       unsigned long i;
-
-       for (i = pgd_index(start); i <= pgd_index(end-1); i++) {
-               next = (addr + PGDIR_SIZE) & PGDIR_MASK;
-               if (next > end || next <= addr)
-                       next = end;
-               
-               clear_pgd_range(tlb, pgd, addr, next);
-               pgd++;
-               addr = next;
-       }
+       pgd_t *pgd;
+       unsigned long next;
+
+       pgd = pgd_offset(tlb->mm, addr);
+       do {
+               next = pgd_addr_end(addr, end);
+               clear_pud_range(tlb, pgd, addr, next);
+       } while (pgd++, addr = next, addr != end);
 }
 
 pte_t fastcall * pte_alloc_map(struct mm_struct *mm, pmd_t *pmd, unsigned long 
address)
-
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