nfsd: dynamically allocate the nfsd-filecache shrinker

Use new APIs to dynamically allocate the nfsd-filecache shrinker.

Link: https://lkml.kernel.org/r/20230911094444.68966-13-zhengqi.arch@bytedance.comSigned-off-by: Qi Zheng <zhengqi.arch@bytedance.com>
Reviewed-by: Muchun Song <songmuchun@bytedance.com>
Cc: Jeff Layton <jlayton@kernel.org>
Cc: Neil Brown <neilb@suse.de>
Cc: Olga Kornievskaia <kolga@netapp.com>
Cc: Dai Ngo <Dai.Ngo@oracle.com>
Cc: Tom Talpey <tom@talpey.com>
Cc: Abhinav Kumar <quic_abhinavk@quicinc.com>
Cc: Alasdair Kergon <agk@redhat.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Alyssa Rosenzweig <alyssa.rosenzweig@collabora.com>
Cc: Andreas Dilger <adilger.kernel@dilger.ca>
Cc: Andreas Gruenbacher <agruenba@redhat.com>
Cc: Anna Schumaker <anna@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Bob Peterson <rpeterso@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Carlos Llamas <cmllamas@google.com>
Cc: Chandan Babu R <chandan.babu@oracle.com>
Cc: Chao Yu <chao@kernel.org>
Cc: Chris Mason <clm@fb.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Christian Koenig <christian.koenig@amd.com>
Cc: Chuck Lever <cel@kernel.org>
Cc: Coly Li <colyli@suse.de>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: "Darrick J. Wong" <djwong@kernel.org>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: David Airlie <airlied@gmail.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Sterba <dsterba@suse.com>
Cc: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Cc: Gao Xiang <hsiangkao@linux.alibaba.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Huang Rui <ray.huang@amd.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jaegeuk Kim <jaegeuk@kernel.org>
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Jason Wang <jasowang@redhat.com>
Cc: Jeffle Xu <jefflexu@linux.alibaba.com>
Cc: Joel Fernandes (Google) <joel@joelfernandes.org>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Josef Bacik <josef@toxicpanda.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Kent Overstreet <kent.overstreet@gmail.com>
Cc: Kirill Tkhai <tkhai@ya.ru>
Cc: Marijn Suijten <marijn.suijten@somainline.org>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Mike Snitzer <snitzer@kernel.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Nadav Amit <namit@vmware.com>
Cc: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>
Cc: Paul E. McKenney <paulmck@kernel.org>
Cc: Richard Weinberger <richard@nod.at>
Cc: Rob Clark <robdclark@gmail.com>
Cc: Rob Herring <robh@kernel.org>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Sean Paul <sean@poorly.run>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Song Liu <song@kernel.org>
Cc: Stefano Stabellini <sstabellini@kernel.org>
Cc: Steven Price <steven.price@arm.com>
Cc: "Theodore Ts'o" <tytso@mit.edu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tomeu Vizoso <tomeu.vizoso@collabora.com>
Cc: Trond Myklebust <trond.myklebust@hammerspace.com>
Cc: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
Cc: Yue Hu <huyue2@coolpad.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

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 +742,19 @@ 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) {
+		ret = -ENOMEM;
+		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 +777,7 @@ 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 +894,7 @@ 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