Merge tag 'sound-4.13-rc8' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai...

[karo-tx-linux.git] / fs / devpts / inode.c

diff --git a/fs/devpts/inode.c b/fs/devpts/inode.c
index 108df2e3602c2c63186b61b2fede52794cb46482..7eae33ffa3fcc1d709790b79225521472c6f8281 100644 (file)
--- a/fs/devpts/inode.c
+++ b/fs/devpts/inode.c
@@ -133,6 +133,50 @@ static inline struct pts_fs_info *DEVPTS_SB(struct super_block *sb)
        return sb->s_fs_info;
 }
 
+static int devpts_ptmx_path(struct path *path)
+{
+       struct super_block *sb;
+       int err;
+
+       /* Has the devpts filesystem already been found? */
+       if (path->mnt->mnt_sb->s_magic == DEVPTS_SUPER_MAGIC)
+               return 0;
+
+       /* Is a devpts filesystem at "pts" in the same directory? */
+       err = path_pts(path);
+       if (err)
+               return err;
+
+       /* Is the path the root of a devpts filesystem? */
+       sb = path->mnt->mnt_sb;
+       if ((sb->s_magic != DEVPTS_SUPER_MAGIC) ||
+           (path->mnt->mnt_root != sb->s_root))
+               return -ENODEV;
+
+       return 0;
+}
+
+struct vfsmount *devpts_mntget(struct file *filp, struct pts_fs_info *fsi)
+{
+       struct path path;
+       int err;
+
+       path = filp->f_path;
+       path_get(&path);
+
+       err = devpts_ptmx_path(&path);
+       dput(path.dentry);
+       if (err) {
+               mntput(path.mnt);
+               path.mnt = ERR_PTR(err);
+       }
+       if (DEVPTS_SB(path.mnt->mnt_sb) != fsi) {
+               mntput(path.mnt);
+               path.mnt = ERR_PTR(-ENODEV);
+       }
+       return path.mnt;
+}
+
 struct pts_fs_info *devpts_acquire(struct file *filp)
 {
        struct pts_fs_info *result;
@@ -143,27 +187,16 @@ struct pts_fs_info *devpts_acquire(struct file *filp)
        path = filp->f_path;
        path_get(&path);
 
-       /* Has the devpts filesystem already been found? */
-       sb = path.mnt->mnt_sb;
-       if (sb->s_magic != DEVPTS_SUPER_MAGIC) {
-               /* Is a devpts filesystem at "pts" in the same directory? */
-               err = path_pts(&path);
-               if (err) {
-                       result = ERR_PTR(err);
-                       goto out;
-               }
-
-               /* Is the path the root of a devpts filesystem? */
-               result = ERR_PTR(-ENODEV);
-               sb = path.mnt->mnt_sb;
-               if ((sb->s_magic != DEVPTS_SUPER_MAGIC) ||
-                   (path.mnt->mnt_root != sb->s_root))
-                       goto out;
+       err = devpts_ptmx_path(&path);
+       if (err) {
+               result = ERR_PTR(err);
+               goto out;
        }
 
        /*
         * pty code needs to hold extra references in case of last /dev/tty close
         */
+       sb = path.mnt->mnt_sb;
        atomic_inc(&sb->s_active);
        result = DEVPTS_SB(sb);