drm/panfrost: dynamically allocate the drm-panfrost shrinker

In preparation for implementing lockless slab shrink, use new APIs to
dynamically allocate the drm-panfrost shrinker, so that it can be freed
asynchronously via RCU. Then it doesn't need to wait for RCU read-side
critical section when releasing the struct panfrost_device.

Link: https://lkml.kernel.org/r/20230911094444.68966-23-zhengqi.arch@bytedance.comSigned-off-by: Qi Zheng <zhengqi.arch@bytedance.com>
Reviewed-by: Steven Price <steven.price@arm.com>
Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Rob Herring <robh@kernel.org>
Cc: Tomeu Vizoso <tomeu.vizoso@collabora.com>
Cc: Alyssa Rosenzweig <alyssa.rosenzweig@collabora.com>
Cc: David Airlie <airlied@gmail.com>
Cc: Abhinav Kumar <quic_abhinavk@quicinc.com>
Cc: Alasdair Kergon <agk@redhat.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
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: Dai Ngo <Dai.Ngo@oracle.com>
Cc: Daniel Vetter <daniel@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 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: Jeff Layton <jlayton@kernel.org>
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: Muchun Song <songmuchun@bytedance.com>
Cc: Nadav Amit <namit@vmware.com>
Cc: Neil Brown <neilb@suse.de>
Cc: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>
Cc: Olga Kornievskaia <kolga@netapp.com>
Cc: Paul E. McKenney <paulmck@kernel.org>
Cc: Richard Weinberger <richard@nod.at>
Cc: Rob Clark <robdclark@gmail.com>
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: "Theodore Ts'o" <tytso@mit.edu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tom Talpey <tom@talpey.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>

drivers/gpu/drm/panfrost/panfrost_device.h

@@ -118,7 +118,7 @@ struct panfrost_device {
 
 	struct mutex shrinker_lock;
 	struct list_head shrinker_list;
-	struct shrinker shrinker;
+	struct shrinker *shrinker;
 
 	struct panfrost_devfreq pfdevfreq;
 };

drivers/gpu/drm/panfrost/panfrost_drv.c

@@ -601,10 +601,14 @@ static int panfrost_probe(struct platform_device *pdev)
 	if (err < 0)
 		goto err_out1;
 
-	panfrost_gem_shrinker_init(ddev);
+	err = panfrost_gem_shrinker_init(ddev);
+	if (err)
+		goto err_out2;
 
 	return 0;
 
+err_out2:
+	drm_dev_unregister(ddev);
 err_out1:
 	pm_runtime_disable(pfdev->dev);
 	panfrost_device_fini(pfdev);

drivers/gpu/drm/panfrost/panfrost_gem.h

@@ -81,7 +81,7 @@ panfrost_gem_mapping_get(struct panfrost_gem_object *bo,
 void panfrost_gem_mapping_put(struct panfrost_gem_mapping *mapping);
 void panfrost_gem_teardown_mappings_locked(struct panfrost_gem_object *bo);
 
-void panfrost_gem_shrinker_init(struct drm_device *dev);
+int panfrost_gem_shrinker_init(struct drm_device *dev);
 void panfrost_gem_shrinker_cleanup(struct drm_device *dev);
 
 #endif /* __PANFROST_GEM_H__ */

drivers/gpu/drm/panfrost/panfrost_gem_shrinker.c

@@ -18,8 +18,7 @@
 static unsigned long
 panfrost_gem_shrinker_count(struct shrinker *shrinker, struct shrink_control *sc)
 {
-	struct panfrost_device *pfdev =
-		container_of(shrinker, struct panfrost_device, shrinker);
+	struct panfrost_device *pfdev = shrinker->private_data;
 	struct drm_gem_shmem_object *shmem;
 	unsigned long count = 0;
 
@@ -65,8 +64,7 @@ static bool panfrost_gem_purge(struct drm_gem_object *obj)
 static unsigned long
 panfrost_gem_shrinker_scan(struct shrinker *shrinker, struct shrink_control *sc)
 {
-	struct panfrost_device *pfdev =
-		container_of(shrinker, struct panfrost_device, shrinker);
+	struct panfrost_device *pfdev = shrinker->private_data;
 	struct drm_gem_shmem_object *shmem, *tmp;
 	unsigned long freed = 0;
 
@@ -97,13 +95,21 @@ panfrost_gem_shrinker_scan(struct shrinker *shrinker, struct shrink_control *sc)
  *
  * This function registers and sets up the panfrost shrinker.
  */
-void panfrost_gem_shrinker_init(struct drm_device *dev)
+int panfrost_gem_shrinker_init(struct drm_device *dev)
 {
 	struct panfrost_device *pfdev = dev->dev_private;
-	pfdev->shrinker.count_objects = panfrost_gem_shrinker_count;
-	pfdev->shrinker.scan_objects = panfrost_gem_shrinker_scan;
-	pfdev->shrinker.seeks = DEFAULT_SEEKS;
-	WARN_ON(register_shrinker(&pfdev->shrinker, "drm-panfrost"));
+
+	pfdev->shrinker = shrinker_alloc(0, "drm-panfrost");
+	if (!pfdev->shrinker)
+		return -ENOMEM;
+
+	pfdev->shrinker->count_objects = panfrost_gem_shrinker_count;
+	pfdev->shrinker->scan_objects = panfrost_gem_shrinker_scan;
+	pfdev->shrinker->private_data = pfdev;
+
+	shrinker_register(pfdev->shrinker);
+
+	return 0;
 }
 
 /**
@@ -116,7 +122,6 @@ void panfrost_gem_shrinker_cleanup(struct drm_device *dev)
 {
 	struct panfrost_device *pfdev = dev->dev_private;
 
-	if (pfdev->shrinker.nr_deferred) {
-		unregister_shrinker(&pfdev->shrinker);
-	}
+	if (pfdev->shrinker)
+		shrinker_free(pfdev->shrinker);
 }