block: Dynamically allocate and refcount backing_dev_info
Instead of storing backing_dev_info inside struct request_queue,
allocate it dynamically, reference count it, and free it when the last
reference is dropped. Currently only request_queue holds the reference
but in the following patch we add other users referencing
backing_dev_info.
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Jens Axboe <axboe@fb.com>
diff --git a/block/blk-core.c b/block/blk-core.c
index dcac035..d2bba47 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -713,7 +713,6 @@ static void blk_rq_timed_out_timer(unsigned long data)
struct request_queue *blk_alloc_queue_node(gfp_t gfp_mask, int node_id)
{
struct request_queue *q;
- int err;
q = kmem_cache_alloc_node(blk_requestq_cachep,
gfp_mask | __GFP_ZERO, node_id);
@@ -728,17 +727,16 @@ struct request_queue *blk_alloc_queue_node(gfp_t gfp_mask, int node_id)
if (!q->bio_split)
goto fail_id;
- q->backing_dev_info = &q->_backing_dev_info;
+ q->backing_dev_info = bdi_alloc_node(gfp_mask, node_id);
+ if (!q->backing_dev_info)
+ goto fail_split;
+
q->backing_dev_info->ra_pages =
(VM_MAX_READAHEAD * 1024) / PAGE_SIZE;
q->backing_dev_info->capabilities = BDI_CAP_CGROUP_WRITEBACK;
q->backing_dev_info->name = "block";
q->node = node_id;
- err = bdi_init(q->backing_dev_info);
- if (err)
- goto fail_split;
-
setup_timer(&q->backing_dev_info->laptop_mode_wb_timer,
laptop_mode_timer_fn, (unsigned long) q);
setup_timer(&q->timeout, blk_rq_timed_out_timer, (unsigned long) q);
@@ -789,7 +787,7 @@ struct request_queue *blk_alloc_queue_node(gfp_t gfp_mask, int node_id)
fail_ref:
percpu_ref_exit(&q->q_usage_counter);
fail_bdi:
- bdi_destroy(q->backing_dev_info);
+ bdi_put(q->backing_dev_info);
fail_split:
bioset_free(q->bio_split);
fail_id: