[PATCH] mm: init_mm without ptlock

[karo-tx-linux.git] / mm / memory.c

diff --git a/mm/memory.c b/mm/memory.c
index 692ad810263de7a3c2d6fa7ecf59953a2413d15d..95a4553c75f708d5d680fe429518f92d605c6381 100644 (file)
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -307,28 +307,22 @@ out:
        return pte_offset_map(pmd, address);
 }
 
-pte_t fastcall * pte_alloc_kernel(struct mm_struct *mm, pmd_t *pmd, unsigned long address)
+pte_t fastcall * pte_alloc_kernel(pmd_t *pmd, unsigned long address)
 {
        if (!pmd_present(*pmd)) {
                pte_t *new;
 
-               spin_unlock(&mm->page_table_lock);
-               new = pte_alloc_one_kernel(mm, address);
-               spin_lock(&mm->page_table_lock);
+               new = pte_alloc_one_kernel(&init_mm, address);
                if (!new)
                        return NULL;
 
-               /*
-                * Because we dropped the lock, we should re-check the
-                * entry, as somebody else could have populated it..
-                */
-               if (pmd_present(*pmd)) {
+               spin_lock(&init_mm.page_table_lock);
+               if (pmd_present(*pmd))
                        pte_free_kernel(new);
-                       goto out;
-               }
-               pmd_populate_kernel(mm, pmd, new);
+               else
+                       pmd_populate_kernel(&init_mm, pmd, new);
+               spin_unlock(&init_mm.page_table_lock);
        }
-out:
        return pte_offset_kernel(pmd, address);
 }
 
@@ -2097,30 +2091,30 @@ int __handle_mm_fault(struct mm_struct *mm, struct vm_area_struct *vma,
 #ifndef __PAGETABLE_PUD_FOLDED
 /*
  * Allocate page upper directory.
- *
- * We've already handled the fast-path in-line, and we own the
- * page table lock.
+ * We've already handled the fast-path in-line.
  */
 pud_t fastcall *__pud_alloc(struct mm_struct *mm, pgd_t *pgd, unsigned long address)
 {
        pud_t *new;
 
-       spin_unlock(&mm->page_table_lock);
+       if (mm != &init_mm)             /* Temporary bridging hack */
+               spin_unlock(&mm->page_table_lock);
        new = pud_alloc_one(mm, address);
-       spin_lock(&mm->page_table_lock);
-       if (!new)
+       if (!new) {
+               if (mm != &init_mm)     /* Temporary bridging hack */
+                       spin_lock(&mm->page_table_lock);
                return NULL;
+       }
 
-       /*
-        * Because we dropped the lock, we should re-check the
-        * entry, as somebody else could have populated it..
-        */
+       spin_lock(&mm->page_table_lock);
        if (pgd_present(*pgd)) {
                pud_free(new);
                goto out;
        }
        pgd_populate(mm, pgd, new);
  out:
+       if (mm == &init_mm)             /* Temporary bridging hack */
+               spin_unlock(&mm->page_table_lock);
        return pud_offset(pgd, address);
 }
 #endif /* __PAGETABLE_PUD_FOLDED */
@@ -2128,24 +2122,22 @@ pud_t fastcall *__pud_alloc(struct mm_struct *mm, pgd_t *pgd, unsigned long addr
 #ifndef __PAGETABLE_PMD_FOLDED
 /*
  * Allocate page middle directory.
- *
- * We've already handled the fast-path in-line, and we own the
- * page table lock.
+ * We've already handled the fast-path in-line.
  */
 pmd_t fastcall *__pmd_alloc(struct mm_struct *mm, pud_t *pud, unsigned long address)
 {
        pmd_t *new;
 
-       spin_unlock(&mm->page_table_lock);
+       if (mm != &init_mm)             /* Temporary bridging hack */
+               spin_unlock(&mm->page_table_lock);
        new = pmd_alloc_one(mm, address);
-       spin_lock(&mm->page_table_lock);
-       if (!new)
+       if (!new) {
+               if (mm != &init_mm)     /* Temporary bridging hack */
+                       spin_lock(&mm->page_table_lock);
                return NULL;
+       }
 
-       /*
-        * Because we dropped the lock, we should re-check the
-        * entry, as somebody else could have populated it..
-        */
+       spin_lock(&mm->page_table_lock);
 #ifndef __ARCH_HAS_4LEVEL_HACK
        if (pud_present(*pud)) {
                pmd_free(new);
@@ -2161,6 +2153,8 @@ pmd_t fastcall *__pmd_alloc(struct mm_struct *mm, pud_t *pud, unsigned long addr
 #endif /* __ARCH_HAS_4LEVEL_HACK */
 
  out:
+       if (mm == &init_mm)             /* Temporary bridging hack */
+               spin_unlock(&mm->page_table_lock);
        return pmd_offset(pud, address);
 }
 #endif /* __PAGETABLE_PMD_FOLDED */