[PATCH v4 18/48] rcu: dynamically allocate the rcu-lazy shrinker

[Qi Zheng <zhengqi.arch@xxxxxxxxxxxxx>]

Use new APIs to dynamically allocate the rcu-lazy shrinker.

Signed-off-by: Qi Zheng <zhengqi.arch@xxxxxxxxxxxxx>
---
 kernel/rcu/tree_nocb.h | 20 +++++++++++---------
 1 file changed, 11 insertions(+), 9 deletions(-)

diff --git a/kernel/rcu/tree_nocb.h b/kernel/rcu/tree_nocb.h
index 5598212d1f27..e1c59c33738a 100644
--- a/kernel/rcu/tree_nocb.h
+++ b/kernel/rcu/tree_nocb.h
@@ -1396,13 +1396,6 @@ lazy_rcu_shrink_scan(struct shrinker *shrink, struct 
shrink_control *sc)
 
        return count ? count : SHRINK_STOP;
 }
-
-static struct shrinker lazy_rcu_shrinker = {
-       .count_objects = lazy_rcu_shrink_count,
-       .scan_objects = lazy_rcu_shrink_scan,
-       .batch = 0,
-       .seeks = DEFAULT_SEEKS,
-};
 #endif // #ifdef CONFIG_RCU_LAZY
 
 void __init rcu_init_nohz(void)
@@ -1410,6 +1403,7 @@ void __init rcu_init_nohz(void)
        int cpu;
        struct rcu_data *rdp;
        const struct cpumask *cpumask = NULL;
+       struct shrinker * __maybe_unused lazy_rcu_shrinker;
 
 #if defined(CONFIG_NO_HZ_FULL)
        if (tick_nohz_full_running && !cpumask_empty(tick_nohz_full_mask))
@@ -1436,8 +1430,16 @@ void __init rcu_init_nohz(void)
                return;
 
 #ifdef CONFIG_RCU_LAZY
-       if (register_shrinker(&lazy_rcu_shrinker, "rcu-lazy"))
-               pr_err("Failed to register lazy_rcu shrinker!\n");
+       lazy_rcu_shrinker = shrinker_alloc(0, "rcu-lazy");
+       if (!lazy_rcu_shrinker) {
+               pr_err("Failed to allocate lazy_rcu shrinker!\n");
+       } else {
+               lazy_rcu_shrinker->count_objects = lazy_rcu_shrink_count;
+               lazy_rcu_shrinker->scan_objects = lazy_rcu_shrink_scan;
+               lazy_rcu_shrinker->seeks = DEFAULT_SEEKS;
+
+               shrinker_register(lazy_rcu_shrinker);
+       }
 #endif // #ifdef CONFIG_RCU_LAZY
 
        if (!cpumask_subset(rcu_nocb_mask, cpu_possible_mask)) {
-- 
2.30.2