Re: [PATCH v4 4/6] NFSD: Refactor find_one_sb_stid() into find_next_sb_stid()

[Jeff Layton <jlayton@kernel.org>]

On Wed, 2026-03-18 at 10:15 -0400, Chuck Lever wrote:
> From: Chuck Lever <chuck.lever@oracle.com>
> 
> Export-scoped state revocation, added in a subsequent commit,
> needs to advance past non-matching stids within the same
> client without restarting from position zero on each call.
> 
> Extract find_next_sb_stid(), which accepts a starting IDR
> position and can resume iteration across multiple calls.
> find_one_sb_stid() becomes a thin wrapper that starts from
> position zero.
> 
> No change in behavior.
> 
> Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
> ---
>  fs/nfsd/nfs4state.c | 25 ++++++++++++++++++++-----
>  1 file changed, 20 insertions(+), 5 deletions(-)
> 
> diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
> index d476192e4b27..891669b32804 100644
> --- a/fs/nfsd/nfs4state.c
> +++ b/fs/nfsd/nfs4state.c
> @@ -1738,25 +1738,40 @@ static void release_openowner(struct nfs4_openowner *oo)
>  	nfs4_put_stateowner(&oo->oo_owner);
>  }
>  
> -static struct nfs4_stid *find_one_sb_stid(struct nfs4_client *clp,
> -					  struct super_block *sb,
> -					  unsigned int sc_types)
> +/*
> + * On return of a non-NULL stid, @id holds that entry's IDR key;
> + * caller must increment @id before the next call to advance past it.
> + */
> +static struct nfs4_stid *find_next_sb_stid(struct nfs4_client *clp,
> +					   struct super_block *sb,
> +					   unsigned int sc_types,
> +					   unsigned long *id)
>  {
> -	unsigned long id, tmp;
>  	struct nfs4_stid *stid;
>  
>  	spin_lock(&clp->cl_lock);
> -	idr_for_each_entry_ul(&clp->cl_stateids, stid, tmp, id)
> +	while ((stid = idr_get_next_ul(&clp->cl_stateids, id)) != NULL) {
>  		if ((stid->sc_type & sc_types) &&
>  		    stid->sc_status == 0 &&
>  		    stid->sc_file->fi_inode->i_sb == sb) {
>  			refcount_inc(&stid->sc_count);
>  			break;
>  		}
> +		(*id)++;
> +	}
>  	spin_unlock(&clp->cl_lock);
>  	return stid;
>  }
>  
> +static struct nfs4_stid *find_one_sb_stid(struct nfs4_client *clp,
> +					  struct super_block *sb,
> +					  unsigned int sc_types)
> +{
> +	unsigned long id = 0;
> +
> +	return find_next_sb_stid(clp, sb, sc_types, &id);
> +}
> +
>  static void revoke_ol_stid(struct nfs4_client *clp,
>  			   struct nfs4_ol_stateid *stp)
>  {

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