Re: [PATCH v1] net: sunrpc: Fix error checking for d_hash_and_lookup()

[Jeff Layton <jlayton@kernel.org>]

On Mon, 2024-08-26 at 15:06 +0800, Yan Zhen wrote:
> The d_hash_and_lookup() function returns either an error pointer or NULL.
> 
> It might be more appropriate to check error using IS_ERR_OR_NULL().
> 
> Signed-off-by: Yan Zhen <yanzhen@vivo.com>
> ---
>  net/sunrpc/rpc_pipe.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/net/sunrpc/rpc_pipe.c b/net/sunrpc/rpc_pipe.c
> index 910a5d850d04..fd03dd46b1f2 100644
> --- a/net/sunrpc/rpc_pipe.c
> +++ b/net/sunrpc/rpc_pipe.c
> @@ -1306,7 +1306,7 @@ rpc_gssd_dummy_populate(struct dentry *root, struct rpc_pipe *pipe_data)
>  
>  	/* We should never get this far if "gssd" doesn't exist */
>  	gssd_dentry = d_hash_and_lookup(root, &q);
> -	if (!gssd_dentry)
> +	if (IS_ERR_OR_NULL(gssd_dentry))
>  		return ERR_PTR(-ENOENT);

This is the routine that fills out rpc_pipefs directory. If this
returns an IS_ERR value, then we should probably return
PTR_ERR(gssd_dentry) instead of -ENOENT.

>  
>  	ret = rpc_populate(gssd_dentry, gssd_dummy_clnt_dir, 0, 1, NULL);
> @@ -1318,7 +1318,7 @@ rpc_gssd_dummy_populate(struct dentry *root, struct rpc_pipe *pipe_data)
>  	q.name = gssd_dummy_clnt_dir[0].name;
>  	q.len = strlen(gssd_dummy_clnt_dir[0].name);
>  	clnt_dentry = d_hash_and_lookup(gssd_dentry, &q);
> -	if (!clnt_dentry) {
> +	if (IS_ERR_OR_NULL(clnt_dentry)) {
>  		__rpc_depopulate(gssd_dentry, gssd_dummy_clnt_dir, 0, 1);
>  		pipe_dentry = ERR_PTR(-ENOENT);
>  		goto out;

Ditto here.

Nice catch, either way though. This definitely should be fixed.
-- 
Jeff Layton <jlayton@kernel.org>