[PATCH 1/4 v5 RESEND] devpts: hoist out check for DEVPTS_SUPER_MAGIC

Christian Brauner
2018-03-13T16:55:24Z

Hoist the check whether we have already found a suitable devpts filesystem
out of devpts_ptmx_path() in preparation for the devpts bind-mount
resolution patch. This is a non-functional change.

Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
Reviewed-by: "Eric W. Biederman" <ebiederm@xmission.com>
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
---
ChangeLog v4->v5:
* dput() dentry
ChangeLog v3->v4:
* patch unchanged
ChangeLog v2->v3:
* patch unchanged
ChangeLog v1->v2:
* patch added
ChangeLog v0->v1:
* patch not present
---
fs/devpts/inode.c | 26 +++++++++++++++-----------
1 file changed, 15 insertions(+), 11 deletions(-)

diff --git a/fs/devpts/inode.c b/fs/devpts/inode.c
index e31d6ed3ec32..71b901936113 100644
--- a/fs/devpts/inode.c
+++ b/fs/devpts/inode.c
@@ -138,10 +138,6 @@ 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)
@@ -159,21 +155,25 @@ static int devpts_ptmx_path(struct path *path)
struct vfsmount *devpts_mntget(struct file *filp, struct pts_fs_info *fsi)
{
struct path path;
- int err;
+ int err = 0;

path = filp->f_path;
path_get(&path);

- err = devpts_ptmx_path(&path);
+ /* Has the devpts filesystem already been found? */
+ if (path.mnt->mnt_sb->s_magic != DEVPTS_SUPER_MAGIC)
+ err = devpts_ptmx_path(&path);
dput(path.dentry);
if (err) {
mntput(path.mnt);
return ERR_PTR(err);
}
+
if (DEVPTS_SB(path.mnt->mnt_sb) != fsi) {
mntput(path.mnt);
return ERR_PTR(-ENODEV);
}
+
return path.mnt;
}

@@ -182,15 +182,19 @@ struct pts_fs_info *devpts_acquire(struct file *filp)
struct pts_fs_info *result;
struct path path;
struct super_block *sb;
- int err;

path = filp->f_path;
path_get(&path);

- err = devpts_ptmx_path(&path);
- if (err) {
- result = ERR_PTR(err);
- goto out;
+ /* Has the devpts filesystem already been found? */
+ if (path.mnt->mnt_sb->s_magic != DEVPTS_SUPER_MAGIC) {
+ int err;
+
+ err = devpts_ptmx_path(&path);
+ if (err) {
+ result = ERR_PTR(err);
+ goto out;
+ }
}

/*
--
2.15.1