Re: [PATCH 6/6] VFS: change lookup_one_common and lookup_noperm_common to take a qstr

[Jeff Layton <jlayton@kernel.org>]

On Wed, 2025-03-19 at 14:01 +1100, NeilBrown wrote:
> From: NeilBrown <neilb@suse.de>
> 
> These function already take a qstr of course, but they also currently
> take a name/len was well and fill in the qstr.
> Now they take a qstr that is already filled in, which is what all the
> callers have.
> 
> Signed-off-by: NeilBrown <neilb@suse.de>
> ---
>  fs/namei.c | 44 +++++++++++++++++++-------------------------
>  1 file changed, 19 insertions(+), 25 deletions(-)
> 
> diff --git a/fs/namei.c b/fs/namei.c
> index 16605f7108c0..e2fb61573f13 100644
> --- a/fs/namei.c
> +++ b/fs/namei.c
> @@ -2833,13 +2833,12 @@ int vfs_path_lookup(struct dentry *dentry, struct vfsmount *mnt,
>  }
>  EXPORT_SYMBOL(vfs_path_lookup);
>  
> -static int lookup_noperm_common(const char *name, struct dentry *base,
> -				  int len,
> -				  struct qstr *this)
> +static int lookup_noperm_common(struct qstr *qname, struct dentry *base)
>  {
> -	this->name = name;
> -	this->len = len;
> -	this->hash = full_name_hash(base, name, len);
> +	const char *name = qname->name;
> +	u32 len = qname->len;
> +
> +	qname->hash = full_name_hash(base, name, len);
>  	if (!len)
>  		return -EACCES;
>  
> @@ -2856,7 +2855,7 @@ static int lookup_noperm_common(const char *name, struct dentry *base,
>  	 * to use its own hash..
>  	 */
>  	if (base->d_flags & DCACHE_OP_HASH) {
> -		int err = base->d_op->d_hash(base, this);
> +		int err = base->d_op->d_hash(base, qname);
>  		if (err < 0)
>  			return err;
>  	}
> @@ -2864,10 +2863,10 @@ static int lookup_noperm_common(const char *name, struct dentry *base,
>  }
>  
>  static int lookup_one_common(struct mnt_idmap *idmap,
> -			     const char *name, struct dentry *base, int len,
> -			     struct qstr *this) {
> +			     struct qstr *qname, struct dentry *base)
> +{
>  	int err;
> -	err = lookup_noperm_common(name, base, len, this);
> +	err = lookup_noperm_common(qname, base);
>  	if (err < 0)
>  		return err;
>  	return inode_permission(idmap, base->d_inode, MAY_EXEC);
> @@ -2888,16 +2887,14 @@ static int lookup_one_common(struct mnt_idmap *idmap,
>   */
>  struct dentry *try_lookup_noperm(struct qstr *name, struct dentry *base)
>  {
> -	struct qstr this;
>  	int err;
>  
>  	WARN_ON_ONCE(!inode_is_locked(base->d_inode));
>  
> -	err = lookup_noperm_common(name->name, base, name->len, &this);
> +	err = lookup_noperm_common(name, base);
>  	if (err)
>  		return ERR_PTR(err);
>  
> -	name->hash = this.hash;
>  	return lookup_dcache(name, base, 0);
>  }
>  EXPORT_SYMBOL(try_lookup_noperm);
> @@ -2915,17 +2912,16 @@ EXPORT_SYMBOL(try_lookup_noperm);
>  struct dentry *lookup_noperm(struct qstr name, struct dentry *base)
>  {
>  	struct dentry *dentry;
> -	struct qstr this;
>  	int err;
>  
>  	WARN_ON_ONCE(!inode_is_locked(base->d_inode));
>  
> -	err = lookup_noperm_common(name.name, base, name.len, &this);
> +	err = lookup_noperm_common(&name, base);
>  	if (err)
>  		return ERR_PTR(err);
>  
> -	dentry = lookup_dcache(&this, base, 0);
> -	return dentry ? dentry : __lookup_slow(&this, base, 0);
> +	dentry = lookup_dcache(&name, base, 0);
> +	return dentry ? dentry : __lookup_slow(&name, base, 0);
>  }
>  EXPORT_SYMBOL(lookup_noperm);
>  
> @@ -2943,17 +2939,16 @@ struct dentry *lookup_one(struct mnt_idmap *idmap, struct qstr name,
>  			  struct dentry *base)
>  {
>  	struct dentry *dentry;
> -	struct qstr this;
>  	int err;
>  
>  	WARN_ON_ONCE(!inode_is_locked(base->d_inode));
>  
> -	err = lookup_one_common(idmap, name.name, base, name.len, &this);
> +	err = lookup_one_common(idmap, &name, base);
>  	if (err)
>  		return ERR_PTR(err);
>  
> -	dentry = lookup_dcache(&this, base, 0);
> -	return dentry ? dentry : __lookup_slow(&this, base, 0);
> +	dentry = lookup_dcache(&name, base, 0);
> +	return dentry ? dentry : __lookup_slow(&name, base, 0);
>  }
>  EXPORT_SYMBOL(lookup_one);
>  
> @@ -2971,17 +2966,16 @@ EXPORT_SYMBOL(lookup_one);
>  struct dentry *lookup_one_unlocked(struct mnt_idmap *idmap,
>  				   struct qstr name, struct dentry *base)
>  {
> -	struct qstr this;
>  	int err;
>  	struct dentry *ret;
>  
> -	err = lookup_one_common(idmap, name.name, base, name.len, &this);
> +	err = lookup_one_common(idmap, &name, base);
>  	if (err)
>  		return ERR_PTR(err);
>  
> -	ret = lookup_dcache(&this, base, 0);
> +	ret = lookup_dcache(&name, base, 0);
>  	if (!ret)
> -		ret = lookup_slow(&this, base, 0);
> +		ret = lookup_slow(&name, base, 0);
>  	return ret;
>  }
>  EXPORT_SYMBOL(lookup_one_unlocked);

Reviewed-by: Jeff Layton <jlayton@kernel.org>