Re: [PATCH] fs: Eliminate a local variable to make the code more clear

From: Hao Lee
Date: Fri Aug 14 2020 - 02:02:15 EST


Ping

On Wed, Jul 29, 2020 at 11:21 PM Hao Lee <haolee.swjtu@xxxxxxxxx> wrote:
>
> The dentry local variable is introduced in 'commit 84d17192d2afd ("get
> rid of full-hash scan on detaching vfsmounts")' to reduce the length of
> some long statements for example
> mutex_lock(&path->dentry->d_inode->i_mutex). We have already used
> inode_lock(dentry->d_inode) to do the same thing now, and its length is
> acceptable. Furthermore, it seems not concise that assign path->dentry
> to local variable dentry in the statement before goto. So, this function
> would be more clear if we eliminate the local variable dentry.
>
> The function logic is not changed.
>
> Signed-off-by: Hao Lee <haolee.swjtu@xxxxxxxxx>
> ---
> fs/namespace.c | 13 ++++++-------
> 1 file changed, 6 insertions(+), 7 deletions(-)
>
> diff --git a/fs/namespace.c b/fs/namespace.c
> index 4a0f600a3328..fcb93586fcc9 100644
> --- a/fs/namespace.c
> +++ b/fs/namespace.c
> @@ -2187,20 +2187,19 @@ static int attach_recursive_mnt(struct mount *source_mnt,
> static struct mountpoint *lock_mount(struct path *path)
> {
> struct vfsmount *mnt;
> - struct dentry *dentry = path->dentry;
> retry:
> - inode_lock(dentry->d_inode);
> - if (unlikely(cant_mount(dentry))) {
> - inode_unlock(dentry->d_inode);
> + inode_lock(path->dentry->d_inode);
> + if (unlikely(cant_mount(path->dentry))) {
> + inode_unlock(path->dentry->d_inode);
> return ERR_PTR(-ENOENT);
> }
> namespace_lock();
> mnt = lookup_mnt(path);
> if (likely(!mnt)) {
> - struct mountpoint *mp = get_mountpoint(dentry);
> + struct mountpoint *mp = get_mountpoint(path->dentry);
> if (IS_ERR(mp)) {
> namespace_unlock();
> - inode_unlock(dentry->d_inode);
> + inode_unlock(path->dentry->d_inode);
> return mp;
> }
> return mp;
> @@ -2209,7 +2208,7 @@ static struct mountpoint *lock_mount(struct path *path)
> inode_unlock(path->dentry->d_inode);
> path_put(path);
> path->mnt = mnt;
> - dentry = path->dentry = dget(mnt->mnt_root);
> + path->dentry = dget(mnt->mnt_root);
> goto retry;
> }
>
> --
> 2.24.1
>