block: fix stacked driver stats init and free
If a driver allocates a queue for stacked usage, then it does
not currently get stats allocated. This causes the later init
of, eg, writeback throttling to blow up. Move the init to the
queue allocation instead.
Additionally, allow a NULL callback unregistration. This avoids
having the caller check for that, fixing another oops on
removal of a block device that doesn't have poll stats allocated.
Fixes: 34dbad5d26e2 ("blk-stat: convert to callback-based statistics reporting")
Signed-off-by: Jens Axboe <axboe@fb.com>
diff --git a/block/blk-core.c b/block/blk-core.c
index 78d04dd..ad388d5e 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -720,6 +720,10 @@
if (!q->backing_dev_info)
goto fail_split;
+ q->stats = blk_alloc_queue_stats();
+ if (!q->stats)
+ goto fail_stats;
+
q->backing_dev_info->ra_pages =
(VM_MAX_READAHEAD * 1024) / PAGE_SIZE;
q->backing_dev_info->capabilities = BDI_CAP_CGROUP_WRITEBACK;
@@ -776,6 +780,8 @@
fail_ref:
percpu_ref_exit(&q->q_usage_counter);
fail_bdi:
+ blk_free_queue_stats(q->stats);
+fail_stats:
bdi_put(q->backing_dev_info);
fail_split:
bioset_free(q->bio_split);
@@ -852,10 +858,6 @@
int blk_init_allocated_queue(struct request_queue *q)
{
- q->stats = blk_alloc_queue_stats();
- if (!q->stats)
- return -ENOMEM;
-
q->fq = blk_alloc_flush_queue(q, NUMA_NO_NODE, q->cmd_size);
if (!q->fq)
return -ENOMEM;