From 27692cd56e2aa6924b49f4361247d707a023484a Mon Sep 17 00:00:00 2001 From: Oleg Nesterov Date: Thu, 9 Oct 2014 15:25:47 -0700 Subject: [PATCH] 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. [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: Oleg Nesterov Cc: Kirill A. Shutemov Cc: Cyrill Gorcunov Cc: "Eric W. Biederman" Acked-by: Greg Ungerer Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- fs/proc/task_nommu.c | 32 ++++++++++++++++++++++++++------ 1 file changed, 26 insertions(+), 6 deletions(-) diff --git a/fs/proc/task_nommu.c b/fs/proc/task_nommu.c index 98c95d2833ea..9019f1de3f72 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); @@ -270,14 +270,34 @@ static int maps_open(struct inode *inode, struct file *file, { struct proc_maps_private *priv; - priv = __seq_open_private(file, ops, sizeof(struct proc_maps_private)); + priv = __seq_open_private(file, ops, sizeof(*priv)); if (!priv) 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); @@ -292,13 +312,13 @@ 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, };