clear_refs: introduce private struct for mm_walk

In the next patch the clear-refs-type will be required in
clear_refs_pte_range funciton, so prepare the walk->private to carry
this info.

Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
Cc: Matt Mackall <mpm@selenic.com>
Cc: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Cc: Glauber Costa <glommer@parallels.com>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 10 insertions, 2 deletions

diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
index dad0809db551..ef6f6c62dfee 100644
--- a/fs/proc/task_mmu.c
+++ b/fs/proc/task_mmu.c
@@ -695,10 +695,15 @@ enum clear_refs_types {
         CLEAR_REFS_LAST,
 };
 
+struct clear_refs_private {
+        struct vm_area_struct *vma;
+};
+
 static int clear_refs_pte_range(pmd_t *pmd, unsigned long addr,
                                 unsigned long end, struct mm_walk *walk)
 {
-        struct vm_area_struct *vma = walk->private;
+        struct clear_refs_private *cp = walk->private;
+        struct vm_area_struct *vma = cp->vma;
         pte_t *pte, ptent;
         spinlock_t *ptl;
         struct page *page;
@@ -753,13 +758,16 @@ static ssize_t clear_refs_write(struct file *file, const char __user *buf,
                 return -ESRCH;
         mm = get_task_mm(task);
         if (mm) {
+                struct clear_refs_private cp = {
+                };
                 struct mm_walk clear_refs_walk = {
                         .pmd_entry = clear_refs_pte_range,
                         .mm = mm,
+                        .private = &cp,
                 };
                 down_read(&mm->mmap_sem);
                 for (vma = mm->mmap; vma; vma = vma->vm_next) {
-                        clear_refs_walk.private = vma;
+                        cp.vma = vma;
                         if (is_vm_hugetlb_page(vma))
                                 continue;
                         /*