mm: do not use mm->nr_pmds on !MMU configurations

mm->nr_pmds doesn't make sense on !MMU configurations

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

2 files changed, 9 insertions, 4 deletions

diff --git a/include/linux/mm.h b/include/linux/mm.h
index af4ff88a11e0..bd52e2f14027 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -1447,13 +1447,15 @@ static inline int __pud_alloc(struct mm_struct *mm, pgd_t *pgd,
 int __pud_alloc(struct mm_struct *mm, pgd_t *pgd, unsigned long address);
 #endif
 
-#ifdef __PAGETABLE_PMD_FOLDED
+#if defined(__PAGETABLE_PMD_FOLDED) || !defined(CONFIG_MMU)
 static inline int __pmd_alloc(struct mm_struct *mm, pud_t *pud,
                                                 unsigned long address)
 {
         return 0;
 }
 
+static inline void mm_nr_pmds_init(struct mm_struct *mm) {}
+
 static inline unsigned long mm_nr_pmds(struct mm_struct *mm)
 {
         return 0;
@@ -1465,6 +1467,11 @@ static inline void mm_dec_nr_pmds(struct mm_struct *mm) {}
 #else
 int __pmd_alloc(struct mm_struct *mm, pud_t *pud, unsigned long address);
 
+static inline void mm_nr_pmds_init(struct mm_struct *mm)
+{
+        atomic_long_set(&mm->nr_pmds, 0);
+}
+
 static inline unsigned long mm_nr_pmds(struct mm_struct *mm)
 {
         return atomic_long_read(&mm->nr_pmds);
diff --git a/kernel/fork.c b/kernel/fork.c
index 66e19c251581..cf65139615a0 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -555,9 +555,7 @@ static struct mm_struct *mm_init(struct mm_struct *mm, struct task_struct *p)
         INIT_LIST_HEAD(&mm->mmlist);
         mm->core_state = NULL;
         atomic_long_set(&mm->nr_ptes, 0);
-#ifndef __PAGETABLE_PMD_FOLDED
-        atomic_long_set(&mm->nr_pmds, 0);
-#endif
+        mm_nr_pmds_init(mm);
         mm->map_count = 0;
         mm->locked_vm = 0;
         mm->pinned_vm = 0;