In preparation for implementing lockless slab shrink, we need to dynamically allocate the dm-bufio 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 dm_bufio_client. Signed-off-by: Qi Zheng <zhengqi.arch@xxxxxxxxxxxxx> --- drivers/md/dm-bufio.c | 23 +++++++++++++---------- 1 file changed, 13 insertions(+), 10 deletions(-) diff --git a/drivers/md/dm-bufio.c b/drivers/md/dm-bufio.c index eea977662e81..9472470d456d 100644 --- a/drivers/md/dm-bufio.c +++ b/drivers/md/dm-bufio.c @@ -963,7 +963,7 @@ struct dm_bufio_client { sector_t start; - struct shrinker shrinker; + struct shrinker *shrinker; struct work_struct shrink_work; atomic_long_t need_shrink; @@ -2385,7 +2385,7 @@ static unsigned long dm_bufio_shrink_scan(struct shrinker *shrink, struct shrink { struct dm_bufio_client *c; - c = container_of(shrink, struct dm_bufio_client, shrinker); + c = shrink->private_data; atomic_long_add(sc->nr_to_scan, &c->need_shrink); queue_work(dm_bufio_wq, &c->shrink_work); @@ -2394,7 +2394,7 @@ static unsigned long dm_bufio_shrink_scan(struct shrinker *shrink, struct shrink static unsigned long dm_bufio_shrink_count(struct shrinker *shrink, struct shrink_control *sc) { - struct dm_bufio_client *c = container_of(shrink, struct dm_bufio_client, shrinker); + struct dm_bufio_client *c = shrink->private_data; unsigned long count = cache_total(&c->cache); unsigned long retain_target = get_retain_buffers(c); unsigned long queued_for_cleanup = atomic_long_read(&c->need_shrink); @@ -2507,14 +2507,15 @@ struct dm_bufio_client *dm_bufio_client_create(struct block_device *bdev, unsign INIT_WORK(&c->shrink_work, shrink_work); atomic_long_set(&c->need_shrink, 0); - c->shrinker.count_objects = dm_bufio_shrink_count; - c->shrinker.scan_objects = dm_bufio_shrink_scan; - c->shrinker.seeks = 1; - c->shrinker.batch = 0; - r = register_shrinker(&c->shrinker, "dm-bufio:(%u:%u)", + c->shrinker = shrinker_alloc_and_init(dm_bufio_shrink_count, + dm_bufio_shrink_scan, 0, 1, 0, c); + if (!c->shrinker) + goto bad; + + r = register_shrinker(c->shrinker, "dm-bufio:(%u:%u)", MAJOR(bdev->bd_dev), MINOR(bdev->bd_dev)); if (r) - goto bad; + goto bad_shrinker; mutex_lock(&dm_bufio_clients_lock); dm_bufio_client_count++; @@ -2524,6 +2525,8 @@ struct dm_bufio_client *dm_bufio_client_create(struct block_device *bdev, unsign return c; +bad_shrinker: + shrinker_free(c->shrinker); bad: while (!list_empty(&c->reserved_buffers)) { struct dm_buffer *b = list_to_buffer(c->reserved_buffers.next); @@ -2554,7 +2557,7 @@ void dm_bufio_client_destroy(struct dm_bufio_client *c) drop_buffers(c); - unregister_shrinker(&c->shrinker); + unregister_and_free_shrinker(c->shrinker); flush_work(&c->shrink_work); mutex_lock(&dm_bufio_clients_lock); -- 2.30.2