1 files changed, 31 insertions, 37 deletions

diff --git a/fs/devpts/inode.c b/fs/devpts/inode.c
index 488eb424f662..4a714f6c1bed 100644
--- a/fs/devpts/inode.c
+++ b/fs/devpts/inode.c
@@ -27,6 +27,7 @@
 #define DEVPTS_SUPER_MAGIC 0x1cd1
 
 #define DEVPTS_DEFAULT_MODE 0600
+#define PTMX_MINOR      2
 
 extern int pty_limit;                   /* Config limit on Unix98 ptys */
 static DEFINE_IDA(allocated_ptys);
@@ -48,7 +49,7 @@ enum {
         Opt_err
 };
 
-static match_table_t tokens = {
+static const match_table_t tokens = {
         {Opt_uid, "uid=%u"},
         {Opt_gid, "gid=%u"},
         {Opt_mode, "mode=%o"},
@@ -169,15 +170,7 @@ static struct file_system_type devpts_fs_type = {
  * to the System V naming convention
  */
 
-static struct dentry *get_node(int num)
-{
-        char s[12];
-        struct dentry *root = devpts_root;
-        mutex_lock(&root->d_inode->i_mutex);
-        return lookup_one_len(s, root, sprintf(s, "%d", num));
-}
-
-int devpts_new_index(void)
+int devpts_new_index(struct inode *ptmx_inode)
 {
         int index;
         int ida_ret;
@@ -205,20 +198,21 @@ retry:
         return index;
 }
 
-void devpts_kill_index(int idx)
+void devpts_kill_index(struct inode *ptmx_inode, int idx)
 {
         mutex_lock(&allocated_ptys_lock);
         ida_remove(&allocated_ptys, idx);
         mutex_unlock(&allocated_ptys_lock);
 }
 
-int devpts_pty_new(struct tty_struct *tty)
+int devpts_pty_new(struct inode *ptmx_inode, struct tty_struct *tty)
 {
         int number = tty->index; /* tty layer puts index from devpts_new_index() in here */
         struct tty_driver *driver = tty->driver;
         dev_t device = MKDEV(driver->major, driver->minor_start+number);
         struct dentry *dentry;
         struct inode *inode = new_inode(devpts_mnt->mnt_sb);
+        char s[12];
 
         /* We're supposed to be given the slave end of a pty */
         BUG_ON(driver->type != TTY_DRIVER_TYPE_PTY);
@@ -233,10 +227,15 @@ int devpts_pty_new(struct tty_struct *tty)
         inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
         init_special_inode(inode, S_IFCHR|config.mode, device);
         inode->i_private = tty;
+        tty->driver_data = inode;
 
-        dentry = get_node(number);
-        if (!IS_ERR(dentry) && !dentry->d_inode) {
-                d_instantiate(dentry, inode);
+        sprintf(s, "%d", number);
+
+        mutex_lock(&devpts_root->d_inode->i_mutex);
+
+        dentry = d_alloc_name(devpts_root, s);
+        if (!IS_ERR(dentry)) {
+                d_add(dentry, inode);
                 fsnotify_create(devpts_root->d_inode, dentry);
         }
 
@@ -245,36 +244,31 @@ int devpts_pty_new(struct tty_struct *tty)
         return 0;
 }
 
-struct tty_struct *devpts_get_tty(int number)
+struct tty_struct *devpts_get_tty(struct inode *pts_inode, int number)
 {
-        struct dentry *dentry = get_node(number);
-        struct tty_struct *tty;
-
-        tty = NULL;
-        if (!IS_ERR(dentry)) {
-                if (dentry->d_inode)
-                        tty = dentry->d_inode->i_private;
-                dput(dentry);
-        }
+        BUG_ON(pts_inode->i_rdev == MKDEV(TTYAUX_MAJOR, PTMX_MINOR));
 
-        mutex_unlock(&devpts_root->d_inode->i_mutex);
-
-        return tty;
+        if (pts_inode->i_sb->s_magic == DEVPTS_SUPER_MAGIC)
+                return (struct tty_struct *)pts_inode->i_private;
+        return NULL;
 }
 
-void devpts_pty_kill(int number)
+void devpts_pty_kill(struct tty_struct *tty)
 {
-        struct dentry *dentry = get_node(number);
+        struct inode *inode = tty->driver_data;
+        struct dentry *dentry;
 
-        if (!IS_ERR(dentry)) {
-                struct inode *inode = dentry->d_inode;
-                if (inode) {
-                        inode->i_nlink--;
-                        d_delete(dentry);
-                        dput(dentry);
-                }
+        BUG_ON(inode->i_rdev == MKDEV(TTYAUX_MAJOR, PTMX_MINOR));
+
+        mutex_lock(&devpts_root->d_inode->i_mutex);
+
+        dentry = d_find_alias(inode);
+        if (dentry && !IS_ERR(dentry)) {
+                inode->i_nlink--;
+                d_delete(dentry);
                 dput(dentry);
         }
+
         mutex_unlock(&devpts_root->d_inode->i_mutex);
 }