Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux...

[karo-tx-linux.git] / fs / proc / task_nommu.c

diff --git a/fs/proc/task_nommu.c b/fs/proc/task_nommu.c
index 678455d2d6839e9ab0df0909905d877aa5debb6a..599ec2e201043ea8f210a7c15a13c4e7eab22440 100644 (file)
--- a/fs/proc/task_nommu.c
+++ b/fs/proc/task_nommu.c
@@ -123,6 +123,25 @@ unsigned long task_statm(struct mm_struct *mm,
        return size;
 }
 
+static pid_t pid_of_stack(struct proc_maps_private *priv,
+                               struct vm_area_struct *vma, bool is_pid)
+{
+       struct inode *inode = priv->inode;
+       struct task_struct *task;
+       pid_t ret = 0;
+
+       rcu_read_lock();
+       task = pid_task(proc_pid(inode), PIDTYPE_PID);
+       if (task) {
+               task = task_of_stack(task, vma, is_pid);
+               if (task)
+                       ret = task_pid_nr_ns(task, inode->i_sb->s_fs_info);
+       }
+       rcu_read_unlock();
+
+       return ret;
+}
+
 /*
  * display a single VMA to a sequenced file
  */
@@ -163,7 +182,7 @@ static int nommu_vma_show(struct seq_file *m, struct vm_area_struct *vma,
                seq_pad(m, ' ');
                seq_path(m, &file->f_path, "");
        } else if (mm) {
-               pid_t tid = vm_is_stack(priv->task, vma, is_pid);
+               pid_t tid = pid_of_stack(priv, vma, is_pid);
 
                if (tid != 0) {
                        seq_pad(m, ' ');
@@ -212,22 +231,22 @@ static void *m_start(struct seq_file *m, loff_t *pos)
        loff_t n = *pos;
 
        /* pin the task and mm whilst we play with them */
-       priv->task = get_pid_task(priv->pid, PIDTYPE_PID);
+       priv->task = get_proc_task(priv->inode);
        if (!priv->task)
                return ERR_PTR(-ESRCH);
 
-       mm = mm_access(priv->task, PTRACE_MODE_READ);
-       if (!mm || IS_ERR(mm)) {
-               put_task_struct(priv->task);
-               priv->task = NULL;
-               return mm;
-       }
-       down_read(&mm->mmap_sem);
+       mm = priv->mm;
+       if (!mm || !atomic_inc_not_zero(&mm->mm_users))
+               return NULL;
 
+       down_read(&mm->mmap_sem);
        /* start from the Nth VMA */
        for (p = rb_first(&mm->mm_rb); p; p = rb_next(p))
                if (n-- == 0)
                        return p;
+
+       up_read(&mm->mmap_sem);
+       mmput(mm);
        return NULL;
 }
 
@@ -235,11 +254,13 @@ static void m_stop(struct seq_file *m, void *_vml)
 {
        struct proc_maps_private *priv = m->private;
 
+       if (!IS_ERR_OR_NULL(_vml)) {
+               up_read(&priv->mm->mmap_sem);
+               mmput(priv->mm);
+       }
        if (priv->task) {
-               struct mm_struct *mm = priv->task->mm;
-               up_read(&mm->mmap_sem);
-               mmput(mm);
                put_task_struct(priv->task);
+               priv->task = NULL;
        }
 }
 
@@ -269,20 +290,33 @@ static int maps_open(struct inode *inode, struct file *file,
                     const struct seq_operations *ops)
 {
        struct proc_maps_private *priv;
-       int ret = -ENOMEM;
-
-       priv = kzalloc(sizeof(*priv), GFP_KERNEL);
-       if (priv) {
-               priv->pid = proc_pid(inode);
-               ret = seq_open(file, ops);
-               if (!ret) {
-                       struct seq_file *m = file->private_data;
-                       m->private = priv;
-               } else {
-                       kfree(priv);
-               }
+
+       priv = __seq_open_private(file, ops, sizeof(*priv));
+       if (!priv)
+               return -ENOMEM;
+
+       priv->inode = inode;
+       priv->mm = proc_mem_open(inode, PTRACE_MODE_READ);
+       if (IS_ERR(priv->mm)) {
+               int err = PTR_ERR(priv->mm);
+
+               seq_release_private(inode, file);
+               return err;
        }
-       return ret;
+
+       return 0;
+}
+
+
+static int map_release(struct inode *inode, struct file *file)
+{
+       struct seq_file *seq = file->private_data;
+       struct proc_maps_private *priv = seq->private;
+
+       if (priv->mm)
+               mmdrop(priv->mm);
+
+       return seq_release_private(inode, file);
 }
 
 static int pid_maps_open(struct inode *inode, struct file *file)
@@ -299,13 +333,13 @@ const struct file_operations proc_pid_maps_operations = {
        .open           = pid_maps_open,
        .read           = seq_read,
        .llseek         = seq_lseek,
-       .release        = seq_release_private,
+       .release        = map_release,
 };
 
 const struct file_operations proc_tid_maps_operations = {
        .open           = tid_maps_open,
        .read           = seq_read,
        .llseek         = seq_lseek,
-       .release        = seq_release_private,
+       .release        = map_release,
 };