Re: [PATCH 1/1] NFSD: replace delayed_work with work_struct for nfsd_client_shrinker

[Jeff Layton <jlayton@kernel.org>]

On Wed, 2023-01-11 at 16:06 -0800, Dai Ngo wrote:
> Since nfsd4_state_shrinker_count always calls mod_delayed_work with
> 0 delay, we can replace delayed_work with work_struct to save some
> space and overhead.
> 
> Also add the call to cancel_work after unregister the shrinker
> in nfs4_state_shutdown_net.
> 
> Signed-off-by: Dai Ngo <dai.ngo@oracle.com>
> ---
>  fs/nfsd/netns.h     | 2 +-
>  fs/nfsd/nfs4state.c | 8 ++++----
>  2 files changed, 5 insertions(+), 5 deletions(-)
> 
> diff --git a/fs/nfsd/netns.h b/fs/nfsd/netns.h
> index 8c854ba3285b..51a4b7885cae 100644
> --- a/fs/nfsd/netns.h
> +++ b/fs/nfsd/netns.h
> @@ -195,7 +195,7 @@ struct nfsd_net {
>  
>  	atomic_t		nfsd_courtesy_clients;
>  	struct shrinker		nfsd_client_shrinker;
> -	struct delayed_work	nfsd_shrinker_work;
> +	struct work_struct	nfsd_shrinker_work;
>  };
>  
>  /* Simple check to find out if a given net was properly initialized */
> diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
> index a7cfefd7c205..21bee33bc6dc 100644
> --- a/fs/nfsd/nfs4state.c
> +++ b/fs/nfsd/nfs4state.c
> @@ -4411,7 +4411,7 @@ nfsd4_state_shrinker_count(struct shrinker *shrink, struct shrink_control *sc)
>  	if (!count)
>  		count = atomic_long_read(&num_delegations);
>  	if (count)
> -		mod_delayed_work(laundry_wq, &nn->nfsd_shrinker_work, 0);
> +		queue_work(laundry_wq, &nn->nfsd_shrinker_work);
>  	return (unsigned long)count;
>  }
>  
> @@ -6233,8 +6233,7 @@ deleg_reaper(struct nfsd_net *nn)
>  static void
>  nfsd4_state_shrinker_worker(struct work_struct *work)
>  {
> -	struct delayed_work *dwork = to_delayed_work(work);
> -	struct nfsd_net *nn = container_of(dwork, struct nfsd_net,
> +	struct nfsd_net *nn = container_of(work, struct nfsd_net,
>  				nfsd_shrinker_work);
>  
>  	courtesy_client_reaper(nn);
> @@ -8064,7 +8063,7 @@ static int nfs4_state_create_net(struct net *net)
>  	INIT_LIST_HEAD(&nn->blocked_locks_lru);
>  
>  	INIT_DELAYED_WORK(&nn->laundromat_work, laundromat_main);
> -	INIT_DELAYED_WORK(&nn->nfsd_shrinker_work, nfsd4_state_shrinker_worker);
> +	INIT_WORK(&nn->nfsd_shrinker_work, nfsd4_state_shrinker_worker);
>  	get_net(net);
>  
>  	nn->nfsd_client_shrinker.scan_objects = nfsd4_state_shrinker_scan;
> @@ -8171,6 +8170,7 @@ nfs4_state_shutdown_net(struct net *net)
>  	struct nfsd_net *nn = net_generic(net, nfsd_net_id);
>  
>  	unregister_shrinker(&nn->nfsd_client_shrinker);
> +	cancel_work(&nn->nfsd_shrinker_work);
>  	cancel_delayed_work_sync(&nn->laundromat_work);
>  	locks_end_grace(&nn->nfsd4_manager);
>  

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