maps4: move clear_refs code to task_mmu.c

This puts all the clear_refs code where it belongs and probably lets things
compile on MMU-less systems as well.

Signed-off-by: Matt Mackall <mpm@selenic.com>
Cc: Jeremy Fitzhardinge <jeremy@goop.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Dave Hansen <haveblue@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 36 insertions, 8 deletions

diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
index abc44f39f1d6..fcdbd233f252 100644
--- a/fs/proc/task_mmu.c
+++ b/fs/proc/task_mmu.c
@@ -323,19 +323,47 @@ static int show_smap(struct seq_file *m, void *v)
 
 static struct mm_walk clear_refs_walk = { .pmd_entry = clear_refs_pte_range };
 
-void clear_refs_smap(struct mm_struct *mm)
+static ssize_t clear_refs_write(struct file *file, const char __user *buf,
+                                size_t count, loff_t *ppos)
 {
+        struct task_struct *task;
+        char buffer[PROC_NUMBUF], *end;
+        struct mm_struct *mm;
         struct vm_area_struct *vma;
 
-        down_read(&mm->mmap_sem);
-        for (vma = mm->mmap; vma; vma = vma->vm_next)
-                if (vma->vm_mm && !is_vm_hugetlb_page(vma))
-                        walk_page_range(vma->vm_mm, vma->vm_start, vma->vm_end,
-                                        &clear_refs_walk, vma);
-        flush_tlb_mm(mm);
-        up_read(&mm->mmap_sem);
+        memset(buffer, 0, sizeof(buffer));
+        if (count > sizeof(buffer) - 1)
+                count = sizeof(buffer) - 1;
+        if (copy_from_user(buffer, buf, count))
+                return -EFAULT;
+        if (!simple_strtol(buffer, &end, 0))
+                return -EINVAL;
+        if (*end == '\n')
+                end++;
+        task = get_proc_task(file->f_path.dentry->d_inode);
+        if (!task)
+                return -ESRCH;
+        mm = get_task_mm(task);
+        if (mm) {
+                down_read(&mm->mmap_sem);
+                for (vma = mm->mmap; vma; vma = vma->vm_next)
+                        if (!is_vm_hugetlb_page(vma))
+                                walk_page_range(mm, vma->vm_start, vma->vm_end,
+                                                &clear_refs_walk, vma);
+                flush_tlb_mm(mm);
+                up_read(&mm->mmap_sem);
+                mmput(mm);
+        }
+        put_task_struct(task);
+        if (end - buffer == 0)
+                return -EIO;
+        return end - buffer;
 }
 
+const struct file_operations proc_clear_refs_operations = {
+        .write          = clear_refs_write,
+};
+
 static void *m_start(struct seq_file *m, loff_t *pos)
 {
         struct proc_maps_private *priv = m->private;