fs/proc/task_mmu.c: shift mm_access() from m_start() to proc_maps_open()

[firefly-linux-kernel-4.4.55.git] / fs / proc / task_mmu.c

diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
index 4d716a09d500fab0b726331a193bbdb4bb064964..a1454dac7e0a64b58ae873731a275d38842b0e63 100644 (file)
--- a/fs/proc/task_mmu.c
+++ b/fs/proc/task_mmu.c
@@ -165,9 +165,9 @@ static void *m_start(struct seq_file *m, loff_t *pos)
        if (!priv->task)
                return ERR_PTR(-ESRCH);
 
-       mm = mm_access(priv->task, PTRACE_MODE_READ);
-       if (!mm || IS_ERR(mm))
-               return mm;
+       mm = priv->mm;
+       if (!mm || !atomic_inc_not_zero(&mm->mm_users))
+               return NULL;
        down_read(&mm->mmap_sem);
 
        tail_vma = get_gate_vma(mm);
@@ -240,9 +240,28 @@ static int proc_maps_open(struct inode *inode, struct file *file,
                return -ENOMEM;
 
        priv->pid = proc_pid(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 0;
 }
 
+static int proc_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 do_maps_open(struct inode *inode, struct file *file,
                        const struct seq_operations *ops)
 {
@@ -398,14 +417,14 @@ const struct file_operations proc_pid_maps_operations = {
        .open           = pid_maps_open,
        .read           = seq_read,
        .llseek         = seq_lseek,
-       .release        = seq_release_private,
+       .release        = proc_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        = proc_map_release,
 };
 
 /*
@@ -680,14 +699,14 @@ const struct file_operations proc_pid_smaps_operations = {
        .open           = pid_smaps_open,
        .read           = seq_read,
        .llseek         = seq_lseek,
-       .release        = seq_release_private,
+       .release        = proc_map_release,
 };
 
 const struct file_operations proc_tid_smaps_operations = {
        .open           = tid_smaps_open,
        .read           = seq_read,
        .llseek         = seq_lseek,
-       .release        = seq_release_private,
+       .release        = proc_map_release,
 };
 
 /*
@@ -1544,13 +1563,13 @@ const struct file_operations proc_pid_numa_maps_operations = {
        .open           = pid_numa_maps_open,
        .read           = seq_read,
        .llseek         = seq_lseek,
-       .release        = seq_release_private,
+       .release        = proc_map_release,
 };
 
 const struct file_operations proc_tid_numa_maps_operations = {
        .open           = tid_numa_maps_open,
        .read           = seq_read,
        .llseek         = seq_lseek,
-       .release        = seq_release_private,
+       .release        = proc_map_release,
 };
 #endif /* CONFIG_NUMA */