Re: [PATCH 05/13] selinux: Use simple_start_creating() / simple_done_creating()

[Jeff Layton <jlayton@kernel.org>]

On Wed, 2026-02-04 at 15:57 +1100, NeilBrown wrote:
> From: NeilBrown <neil@brown.name>
> 
> Instead of explicitly locking the parent and performing a lookup in
> selinux, use simple_start_creating(), and then use
> simple_done_creating() to unlock.
> 
> This extends the region that the directory is locked for, and also
> performs a lookup.
> The lock extension is of no real consequence.
> The lookup uses simple_lookup() and so always succeeds.  Thus when
> d_make_persistent() is called the dentry will already be hashed.
> d_make_persistent() handles this case.
> 
> Signed-off-by: NeilBrown <neil@brown.name>
> ---
>  security/selinux/selinuxfs.c | 15 +++++++--------
>  1 file changed, 7 insertions(+), 8 deletions(-)
> 
> diff --git a/security/selinux/selinuxfs.c b/security/selinux/selinuxfs.c
> index 896acad1f5f7..97e02cd5a9dc 100644
> --- a/security/selinux/selinuxfs.c
> +++ b/security/selinux/selinuxfs.c
> @@ -1930,15 +1930,16 @@ static const struct inode_operations swapover_dir_inode_operations = {
>  static struct dentry *sel_make_swapover_dir(struct super_block *sb,
>  						unsigned long *ino)
>  {
> -	struct dentry *dentry = d_alloc_name(sb->s_root, ".swapover");
> +	struct dentry *dentry;
>  	struct inode *inode;
>  
> -	if (!dentry)
> +	inode = sel_make_inode(sb, S_IFDIR);
> +	if (!inode)
>  		return ERR_PTR(-ENOMEM);
>  
> -	inode = sel_make_inode(sb, S_IFDIR);
> -	if (!inode) {
> -		dput(dentry);
> +	dentry = simple_start_creating(sb->s_root, ".swapover");
> +	if (!dentry) {
> +		iput(inode);
>  		return ERR_PTR(-ENOMEM);
>  	}
>  
> @@ -1946,11 +1947,9 @@ static struct dentry *sel_make_swapover_dir(struct super_block *sb,
>  	inode->i_ino = ++(*ino);
>  	/* directory inodes start off with i_nlink == 2 (for "." entry) */
>  	inc_nlink(inode);
> -	inode_lock(sb->s_root->d_inode);
>  	d_make_persistent(dentry, inode);
>  	inc_nlink(sb->s_root->d_inode);
> -	inode_unlock(sb->s_root->d_inode);
> -	dput(dentry);
> +	simple_done_creating(dentry);
>  	return dentry;	// borrowed
>  }
>  

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