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From:   Qi Zheng <qi.zheng@linux.dev>
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        linux-btrfs@vger.kernel.org, Qi Zheng <zhengqi.arch@bytedance.com>
Subject: [PATCH 04/29] drm/msm: dynamically allocate the drm-msm_gem shrinker
Date:   Thu, 22 Jun 2023 08:39:07 +0000
Message-Id: <20230622083932.4090339-5-qi.zheng@linux.dev>
In-Reply-To: <20230622083932.4090339-1-qi.zheng@linux.dev>
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From: Qi Zheng <zhengqi.arch@bytedance.com>

In preparation for implementing lockless slab shrink,
we need to dynamically allocate the drm-msm_gem shrinker,
so that it can be freed asynchronously using kfree_rcu().
Then it doesn't need to wait for RCU read-side critical
section when releasing the struct msm_drm_private.

Signed-off-by: Qi Zheng <zhengqi.arch@bytedance.com>
---
 drivers/gpu/drm/msm/msm_drv.h          |  2 +-
 drivers/gpu/drm/msm/msm_gem_shrinker.c | 25 ++++++++++++++-----------
 2 files changed, 15 insertions(+), 12 deletions(-)

diff --git a/drivers/gpu/drm/msm/msm_drv.h b/drivers/gpu/drm/msm/msm_drv.h
index e13a8cbd61c9..4f3ba55058cd 100644
--- a/drivers/gpu/drm/msm/msm_drv.h
+++ b/drivers/gpu/drm/msm/msm_drv.h
@@ -217,7 +217,7 @@ struct msm_drm_private {
 	} vram;
 
 	struct notifier_block vmap_notifier;
-	struct shrinker shrinker;
+	struct shrinker *shrinker;
 
 	struct drm_atomic_state *pm_state;
 
diff --git a/drivers/gpu/drm/msm/msm_gem_shrinker.c b/drivers/gpu/drm/msm/msm_gem_shrinker.c
index f38296ad8743..db7582ae1f19 100644
--- a/drivers/gpu/drm/msm/msm_gem_shrinker.c
+++ b/drivers/gpu/drm/msm/msm_gem_shrinker.c
@@ -34,8 +34,7 @@ static bool can_block(struct shrink_control *sc)
 static unsigned long
 msm_gem_shrinker_count(struct shrinker *shrinker, struct shrink_control *sc)
 {
-	struct msm_drm_private *priv =
-		container_of(shrinker, struct msm_drm_private, shrinker);
+	struct msm_drm_private *priv = shrinker->private_data;
 	unsigned count = priv->lru.dontneed.count;
 
 	if (can_swap())
@@ -100,8 +99,7 @@ active_evict(struct drm_gem_object *obj)
 static unsigned long
 msm_gem_shrinker_scan(struct shrinker *shrinker, struct shrink_control *sc)
 {
-	struct msm_drm_private *priv =
-		container_of(shrinker, struct msm_drm_private, shrinker);
+	struct msm_drm_private *priv = shrinker->private_data;
 	struct {
 		struct drm_gem_lru *lru;
 		bool (*shrink)(struct drm_gem_object *obj);
@@ -151,7 +149,7 @@ msm_gem_shrinker_shrink(struct drm_device *dev, unsigned long nr_to_scan)
 	int ret;
 
 	fs_reclaim_acquire(GFP_KERNEL);
-	ret = msm_gem_shrinker_scan(&priv->shrinker, &sc);
+	ret = msm_gem_shrinker_scan(priv->shrinker, &sc);
 	fs_reclaim_release(GFP_KERNEL);
 
 	return ret;
@@ -213,10 +211,15 @@ msm_gem_shrinker_vmap(struct notifier_block *nb, unsigned long event, void *ptr)
 void msm_gem_shrinker_init(struct drm_device *dev)
 {
 	struct msm_drm_private *priv = dev->dev_private;
-	priv->shrinker.count_objects = msm_gem_shrinker_count;
-	priv->shrinker.scan_objects = msm_gem_shrinker_scan;
-	priv->shrinker.seeks = DEFAULT_SEEKS;
-	WARN_ON(register_shrinker(&priv->shrinker, "drm-msm_gem"));
+
+	priv->shrinker = shrinker_alloc_and_init(msm_gem_shrinker_count,
+						 msm_gem_shrinker_scan, 0,
+						 DEFAULT_SEEKS, 0, priv);
+	if (priv->shrinker &&
+	    register_shrinker(priv->shrinker, "drm-msm_gem")) {
+		shrinker_free(priv->shrinker);
+		WARN_ON(1);
+	}
 
 	priv->vmap_notifier.notifier_call = msm_gem_shrinker_vmap;
 	WARN_ON(register_vmap_purge_notifier(&priv->vmap_notifier));
@@ -232,8 +235,8 @@ void msm_gem_shrinker_cleanup(struct drm_device *dev)
 {
 	struct msm_drm_private *priv = dev->dev_private;
 
-	if (priv->shrinker.nr_deferred) {
+	if (priv->shrinker->nr_deferred) {
 		WARN_ON(unregister_vmap_purge_notifier(&priv->vmap_notifier));
-		unregister_shrinker(&priv->shrinker);
+		unregister_and_free_shrinker(priv->shrinker);
 	}
 }
-- 
2.30.2