Re: [PATCH v3 16/49] nfsd: dynamically allocate the nfsd-filecache shrinker

[Qi Zheng <zhengqi.arch@xxxxxxxxxxxxx>]

On 2023/7/27 16:04, Qi Zheng wrote:
> Use new APIs to dynamically allocate the nfsd-filecache shrinker.
>
> Signed-off-by: Qi Zheng <zhengqi.arch@xxxxxxxxxxxxx>
> Reviewed-by: Muchun Song <songmuchun@xxxxxxxxxxxxx>
> ---
>   fs/nfsd/filecache.c | 22 ++++++++++++----------
>   1 file changed, 12 insertions(+), 10 deletions(-)
>
> diff --git a/fs/nfsd/filecache.c b/fs/nfsd/filecache.c
> index ee9c923192e0..872eb9501965 100644
> --- a/fs/nfsd/filecache.c
> +++ b/fs/nfsd/filecache.c
> @@ -521,11 +521,7 @@ nfsd_file_lru_scan(struct shrinker *s, struct shrink_control *sc)
>   	return ret;
>   }
>   
> -static struct shrinker	nfsd_file_shrinker = {
> -	.scan_objects = nfsd_file_lru_scan,
> -	.count_objects = nfsd_file_lru_count,
> -	.seeks = 1,
> -};
> +static struct shrinker *nfsd_file_shrinker;
>   
>   /**
>    * nfsd_file_cond_queue - conditionally unhash and queue a nfsd_file
> @@ -746,12 +742,18 @@ nfsd_file_cache_init(void)
>   		goto out_err;
>   	}
>   
> -	ret = register_shrinker(&nfsd_file_shrinker, "nfsd-filecache");
> -	if (ret) {
> -		pr_err("nfsd: failed to register nfsd_file_shrinker: %d\n", ret);
> +	nfsd_file_shrinker = shrinker_alloc(0, "nfsd-filecache");
> +	if (!nfsd_file_shrinker) {

Here should set ret to -ENOMEM, will fix.

> +		pr_err("nfsd: failed to allocate nfsd_file_shrinker\n");
>   		goto out_lru;
>   	}
>   
> +	nfsd_file_shrinker->count_objects = nfsd_file_lru_count;
> +	nfsd_file_shrinker->scan_objects = nfsd_file_lru_scan;
> +	nfsd_file_shrinker->seeks = 1;
> +
> +	shrinker_register(nfsd_file_shrinker);
> +
>   	ret = lease_register_notifier(&nfsd_file_lease_notifier);
>   	if (ret) {
>   		pr_err("nfsd: unable to register lease notifier: %d\n", ret);
> @@ -774,7 +776,7 @@ nfsd_file_cache_init(void)
>   out_notifier:
>   	lease_unregister_notifier(&nfsd_file_lease_notifier);
>   out_shrinker:
> -	unregister_shrinker(&nfsd_file_shrinker);
> +	shrinker_free(nfsd_file_shrinker);
>   out_lru:
>   	list_lru_destroy(&nfsd_file_lru);
>   out_err:
> @@ -891,7 +893,7 @@ nfsd_file_cache_shutdown(void)
>   		return;
>   
>   	lease_unregister_notifier(&nfsd_file_lease_notifier);
> -	unregister_shrinker(&nfsd_file_shrinker);
> +	shrinker_free(nfsd_file_shrinker);
>   	/*
>   	 * make sure all callers of nfsd_file_lru_cb are done before
>   	 * calling nfsd_file_cache_purge