[PATCH v6 10/45] NFSv4.2: dynamically allocate the nfs-xattr shrinkers

[Qi Zheng]

Use new APIs to dynamically allocate the nfs-xattr shrinkers.

Signed-off-by: Qi Zheng <zhengqi.arch@xxxxxxxxxxxxx>
Reviewed-by: Muchun Song <songmuchun@xxxxxxxxxxxxx>
CC: Trond Myklebust <trond.myklebust@xxxxxxxxxxxxxxx>
CC: Anna Schumaker <anna@xxxxxxxxxx>
CC: linux-nfs@xxxxxxxxxxxxxxx
---
 fs/nfs/nfs42xattr.c | 87 +++++++++++++++++++++++----------------------
 1 file changed, 44 insertions(+), 43 deletions(-)

diff --git a/fs/nfs/nfs42xattr.c b/fs/nfs/nfs42xattr.c
index 911f634ba3da..2ad66a8922f4 100644
--- a/fs/nfs/nfs42xattr.c
+++ b/fs/nfs/nfs42xattr.c
@@ -796,28 +796,9 @@ static unsigned long nfs4_xattr_cache_scan(struct shrinker *shrink,
 static unsigned long nfs4_xattr_entry_scan(struct shrinker *shrink,
 					   struct shrink_control *sc);
 
-static struct shrinker nfs4_xattr_cache_shrinker = {
-	.count_objects	= nfs4_xattr_cache_count,
-	.scan_objects	= nfs4_xattr_cache_scan,
-	.seeks		= DEFAULT_SEEKS,
-	.flags		= SHRINKER_MEMCG_AWARE,
-};
-
-static struct shrinker nfs4_xattr_entry_shrinker = {
-	.count_objects	= nfs4_xattr_entry_count,
-	.scan_objects	= nfs4_xattr_entry_scan,
-	.seeks		= DEFAULT_SEEKS,
-	.batch		= 512,
-	.flags		= SHRINKER_MEMCG_AWARE,
-};
-
-static struct shrinker nfs4_xattr_large_entry_shrinker = {
-	.count_objects	= nfs4_xattr_entry_count,
-	.scan_objects	= nfs4_xattr_entry_scan,
-	.seeks		= 1,
-	.batch		= 512,
-	.flags		= SHRINKER_MEMCG_AWARE,
-};
+static struct shrinker *nfs4_xattr_cache_shrinker;
+static struct shrinker *nfs4_xattr_entry_shrinker;
+static struct shrinker *nfs4_xattr_large_entry_shrinker;
 
 static enum lru_status
 cache_lru_isolate(struct list_head *item,
@@ -943,7 +924,7 @@ nfs4_xattr_entry_scan(struct shrinker *shrink, struct shrink_control *sc)
 	struct nfs4_xattr_entry *entry;
 	struct list_lru *lru;
 
-	lru = (shrink == &nfs4_xattr_large_entry_shrinker) ?
+	lru = (shrink == nfs4_xattr_large_entry_shrinker) ?
 	    &nfs4_xattr_large_entry_lru : &nfs4_xattr_entry_lru;
 
 	freed = list_lru_shrink_walk(lru, sc, entry_lru_isolate, &dispose);
@@ -971,7 +952,7 @@ nfs4_xattr_entry_count(struct shrinker *shrink, struct shrink_control *sc)
 	unsigned long count;
 	struct list_lru *lru;
 
-	lru = (shrink == &nfs4_xattr_large_entry_shrinker) ?
+	lru = (shrink == nfs4_xattr_large_entry_shrinker) ?
 	    &nfs4_xattr_large_entry_lru : &nfs4_xattr_entry_lru;
 
 	count = list_lru_shrink_count(lru, sc);
@@ -991,18 +972,34 @@ static void nfs4_xattr_cache_init_once(void *p)
 	INIT_LIST_HEAD(&cache->dispose);
 }
 
-static int nfs4_xattr_shrinker_init(struct shrinker *shrinker,
-				    struct list_lru *lru, const char *name)
+typedef unsigned long (*count_objects_cb)(struct shrinker *s,
+					  struct shrink_control *sc);
+typedef unsigned long (*scan_objects_cb)(struct shrinker *s,
+					 struct shrink_control *sc);
+
+static int __init nfs4_xattr_shrinker_init(struct shrinker **shrinker,
+					   struct list_lru *lru, const char *name,
+					   count_objects_cb count,
+					   scan_objects_cb scan, long batch, int seeks)
 {
-	int ret = 0;
+	int ret;
 
-	ret = register_shrinker(shrinker, name);
-	if (ret)
+	*shrinker = shrinker_alloc(SHRINKER_MEMCG_AWARE, name);
+	if (!*shrinker)
+		return -ENOMEM;
+
+	ret = list_lru_init_memcg(lru, *shrinker);
+	if (ret) {
+		shrinker_free(*shrinker);
 		return ret;
+	}
 
-	ret = list_lru_init_memcg(lru, shrinker);
-	if (ret)
-		unregister_shrinker(shrinker);
+	(*shrinker)->count_objects = count;
+	(*shrinker)->scan_objects = scan;
+	(*shrinker)->batch = batch;
+	(*shrinker)->seeks = seeks;
+
+	shrinker_register(*shrinker);
 
 	return ret;
 }
@@ -1010,7 +1007,7 @@ static int nfs4_xattr_shrinker_init(struct shrinker *shrinker,
 static void nfs4_xattr_shrinker_destroy(struct shrinker *shrinker,
 					struct list_lru *lru)
 {
-	unregister_shrinker(shrinker);
+	shrinker_free(shrinker);
 	list_lru_destroy(lru);
 }
 
@@ -1026,27 +1023,31 @@ int __init nfs4_xattr_cache_init(void)
 		return -ENOMEM;
 
 	ret = nfs4_xattr_shrinker_init(&nfs4_xattr_cache_shrinker,
-				       &nfs4_xattr_cache_lru,
-				       "nfs-xattr_cache");
+				       &nfs4_xattr_cache_lru, "nfs-xattr_cache",
+				       nfs4_xattr_cache_count,
+				       nfs4_xattr_cache_scan, 0, DEFAULT_SEEKS);
 	if (ret)
 		goto out1;
 
 	ret = nfs4_xattr_shrinker_init(&nfs4_xattr_entry_shrinker,
-				       &nfs4_xattr_entry_lru,
-				       "nfs-xattr_entry");
+				       &nfs4_xattr_entry_lru, "nfs-xattr_entry",
+				       nfs4_xattr_entry_count,
+				       nfs4_xattr_entry_scan, 512, DEFAULT_SEEKS);
 	if (ret)
 		goto out2;
 
 	ret = nfs4_xattr_shrinker_init(&nfs4_xattr_large_entry_shrinker,
 				       &nfs4_xattr_large_entry_lru,
-				       "nfs-xattr_large_entry");
+				       "nfs-xattr_large_entry",
+				       nfs4_xattr_entry_count,
+				       nfs4_xattr_entry_scan, 512, 1);
 	if (!ret)
 		return 0;
 
-	nfs4_xattr_shrinker_destroy(&nfs4_xattr_entry_shrinker,
+	nfs4_xattr_shrinker_destroy(nfs4_xattr_entry_shrinker,
 				    &nfs4_xattr_entry_lru);
 out2:
-	nfs4_xattr_shrinker_destroy(&nfs4_xattr_cache_shrinker,
+	nfs4_xattr_shrinker_destroy(nfs4_xattr_cache_shrinker,
 				    &nfs4_xattr_cache_lru);
 out1:
 	kmem_cache_destroy(nfs4_xattr_cache_cachep);
@@ -1056,11 +1057,11 @@ int __init nfs4_xattr_cache_init(void)
 
 void nfs4_xattr_cache_exit(void)
 {
-	nfs4_xattr_shrinker_destroy(&nfs4_xattr_large_entry_shrinker,
+	nfs4_xattr_shrinker_destroy(nfs4_xattr_large_entry_shrinker,
 				    &nfs4_xattr_large_entry_lru);
-	nfs4_xattr_shrinker_destroy(&nfs4_xattr_entry_shrinker,
+	nfs4_xattr_shrinker_destroy(nfs4_xattr_entry_shrinker,
 				    &nfs4_xattr_entry_lru);
-	nfs4_xattr_shrinker_destroy(&nfs4_xattr_cache_shrinker,
+	nfs4_xattr_shrinker_destroy(nfs4_xattr_cache_shrinker,
 				    &nfs4_xattr_cache_lru);
 	kmem_cache_destroy(nfs4_xattr_cache_cachep);
 }
-- 
2.30.2