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Subject[PATCH 2/3] fs/proc/task_nommu.c: shift mm_access() from m_start() to proc_maps_open()
Copy-and-paste the changes from "fs/proc/task_mmu.c: shift mm_access()
from m_start() to proc_maps_open()" into task_nommu.c.

Change maps_open() to initialize priv->mm using proc_mem_open(), m_start()
can rely on atomic_inc_not_zero(mm_users) like task_mmu.c does.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
---
fs/proc/task_nommu.c | 29 ++++++++++++++++++++++++-----
1 files changed, 24 insertions(+), 5 deletions(-)

diff --git a/fs/proc/task_nommu.c b/fs/proc/task_nommu.c
index c12eab3..003f2be 100644
--- a/fs/proc/task_nommu.c
+++ b/fs/proc/task_nommu.c
@@ -216,11 +216,11 @@ 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)) {
+ mm = priv->mm;
+ if (!mm || !atomic_inc_not_zero(&mm->mm_users)) {
put_task_struct(priv->task);
priv->task = NULL;
- return mm;
+ return NULL;
}
down_read(&mm->mmap_sem);

@@ -274,9 +274,28 @@ static int 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 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)
{
return maps_open(inode, file, &proc_pid_maps_ops);
@@ -291,13 +310,13 @@ 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,
};

--
1.5.5.1


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