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 abc44f39f1d..fcdbd233f25 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;