Convert i386 ioremap pagetable walkers to loops using p?d_addr_end.
Rename internal levels ioremap_p??_range.  Don't cheat, give it a real
(but inlined) ioremap_pud_range; uninline lowest level to help debug.
Replace "page already exists" printk and BUG by BUG_ON.

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

 arch/i386/mm/ioremap.c |  112 +++++++++++++++++++++++--------------------------
 1 files changed, 53 insertions(+), 59 deletions(-)

--- ptwalk5/arch/i386/mm/ioremap.c      2005-03-09 01:12:39.000000000 +0000
+++ ptwalk6/arch/i386/mm/ioremap.c      2005-03-09 01:36:51.000000000 +0000
@@ -20,89 +20,82 @@
 #define ISA_START_ADDRESS      0xa0000
 #define ISA_END_ADDRESS                0x100000
 
-static inline void remap_area_pte(pte_t * pte, unsigned long address, unsigned 
long size,
-       unsigned long phys_addr, unsigned long flags)
+static int ioremap_pte_range(pmd_t *pmd, unsigned long addr,
+               unsigned long end, unsigned long phys_addr, unsigned long flags)
 {
-       unsigned long end;
+       pte_t *pte;
        unsigned long pfn;
 
-       address &= ~PMD_MASK;
-       end = address + size;
-       if (end > PMD_SIZE)
-               end = PMD_SIZE;
-       if (address >= end)
-               BUG();
        pfn = phys_addr >> PAGE_SHIFT;
+       pte = pte_alloc_kernel(&init_mm, pmd, addr);
+       if (!pte)
+               return -ENOMEM;
        do {
-               if (!pte_none(*pte)) {
-                       printk("remap_area_pte: page already exists\n");
-                       BUG();
-               }
+               BUG_ON(!pte_none(*pte));
                set_pte(pte, pfn_pte(pfn, __pgprot(_PAGE_PRESENT | _PAGE_RW | 
                                        _PAGE_DIRTY | _PAGE_ACCESSED | flags)));
-               address += PAGE_SIZE;
                pfn++;
-               pte++;
-       } while (address && (address < end));
+       } while (pte++, addr += PAGE_SIZE, addr != end);
+       return 0;
 }
 
-static inline int remap_area_pmd(pmd_t * pmd, unsigned long address, unsigned 
long size,
-       unsigned long phys_addr, unsigned long flags)
+static inline int ioremap_pmd_range(pud_t *pud, unsigned long addr,
+               unsigned long end, unsigned long phys_addr, unsigned long flags)
 {
-       unsigned long end;
+       pmd_t *pmd;
+       unsigned long next;
 
-       address &= ~PGDIR_MASK;
-       end = address + size;
-       if (end > PGDIR_SIZE)
-               end = PGDIR_SIZE;
-       phys_addr -= address;
-       if (address >= end)
-               BUG();
+       phys_addr -= addr;
+       pmd = pmd_alloc(&init_mm, pud, addr);
+       if (!pmd)
+               return -ENOMEM;
        do {
-               pte_t * pte = pte_alloc_kernel(&init_mm, pmd, address);
-               if (!pte)
+               next = pmd_addr_end(addr, end);
+               if (ioremap_pte_range(pmd, addr, next, phys_addr + addr, flags))
                        return -ENOMEM;
-               remap_area_pte(pte, address, end - address, address + 
phys_addr, flags);
-               address = (address + PMD_SIZE) & PMD_MASK;
-               pmd++;
-       } while (address && (address < end));
+       } while (pmd++, addr = next, addr != end);
        return 0;
 }
 
-static int remap_area_pages(unsigned long address, unsigned long phys_addr,
-                                unsigned long size, unsigned long flags)
+static inline int ioremap_pud_range(pgd_t *pgd, unsigned long addr,
+               unsigned long end, unsigned long phys_addr, unsigned long flags)
 {
-       int error;
-       pgd_t * dir;
-       unsigned long end = address + size;
+       pud_t *pud;
+       unsigned long next;
 
-       phys_addr -= address;
-       dir = pgd_offset(&init_mm, address);
+       phys_addr -= addr;
+       pud = pud_alloc(&init_mm, pgd, addr);
+       if (!pud)
+               return -ENOMEM;
+       do {
+               next = pud_addr_end(addr, end);
+               if (ioremap_pmd_range(pud, addr, next, phys_addr + addr, flags))
+                       return -ENOMEM;
+       } while (pud++, addr = next, addr != end);
+       return 0;
+}
+
+static int ioremap_page_range(unsigned long addr,
+               unsigned long end, unsigned long phys_addr, unsigned long flags)
+{
+       pgd_t *pgd;
+       unsigned long next;
+       int err;
+
+       BUG_ON(addr >= end);
        flush_cache_all();
-       if (address >= end)
-               BUG();
+       phys_addr -= addr;
+       pgd = pgd_offset_k(addr);
        spin_lock(&init_mm.page_table_lock);
        do {
-               pud_t *pud;
-               pmd_t *pmd;
-               
-               error = -ENOMEM;
-               pud = pud_alloc(&init_mm, dir, address);
-               if (!pud)
-                       break;
-               pmd = pmd_alloc(&init_mm, pud, address);
-               if (!pmd)
-                       break;
-               if (remap_area_pmd(pmd, address, end - address,
-                                        phys_addr + address, flags))
+               next = pgd_addr_end(addr, end);
+               err = ioremap_pud_range(pgd, addr, next, phys_addr+addr, flags);
+               if (err)
                        break;
-               error = 0;
-               address = (address + PGDIR_SIZE) & PGDIR_MASK;
-               dir++;
-       } while (address && (address < end));
+       } while (pgd++, addr = next, addr != end);
        spin_unlock(&init_mm.page_table_lock);
        flush_tlb_all();
-       return error;
+       return err;
 }
 
 /*
@@ -165,7 +158,8 @@ void __iomem * __ioremap(unsigned long p
                return NULL;
        area->phys_addr = phys_addr;
        addr = (void __iomem *) area->addr;
-       if (remap_area_pages((unsigned long) addr, phys_addr, size, flags)) {
+       if (ioremap_page_range((unsigned long) addr,
+                       (unsigned long) addr + size, phys_addr, flags)) {
                vunmap((void __force *) addr);
                return NULL;
        }
-
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