[PATCH v4 13/48] NFSv4.2: dynamically allocate the nfs-xattr shrinkers

[Qi Zheng <zhengqi.arch@xxxxxxxxxxxxx>]

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

Signed-off-by: Qi Zheng <zhengqi.arch@xxxxxxxxxxxxx>
Reviewed-by: Muchun Song <songmuchun@xxxxxxxxxxxxx>
---
 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