path: root/block
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authorSaravanan D <>2021-04-07 10:59:58 -0700
committerJens Axboe <>2021-04-16 15:17:01 -0600
commit1e91e28e374d0b0b912154c192716374609360d9 (patch)
tree74d86b7e80d7a9702c5812df61f748230be887ee /block
parent7687b38ae470f01749e420079c36cccb24b8619a (diff)
blk-mq: Fix spurious debugfs directory creation during initialization
blk_mq_debugfs_register_sched_hctx() called from device_add_disk()->elevator_init_mq()->blk_mq_init_sched() initialization sequence does not have relevant parent directory setup and thus spuriously attempts "sched" directory creation from root mount of debugfs for every hw queue detected on the block device dmesg ... debugfs: Directory 'sched' with parent '/' already present! debugfs: Directory 'sched' with parent '/' already present! . . debugfs: Directory 'sched' with parent '/' already present! ... The parent debugfs directory for hw queues get properly setup device_add_disk()->blk_register_queue()->blk_mq_debugfs_register() ->blk_mq_debugfs_register_hctx() later in the block device initialization sequence. A simple check for debugfs_dir has been added to thwart premature debugfs directory/file creation attempts. Signed-off-by: Saravanan D <> Signed-off-by: Jens Axboe <>
Diffstat (limited to 'block')
1 files changed, 8 insertions, 0 deletions
diff --git a/block/blk-mq-debugfs.c b/block/blk-mq-debugfs.c
index 9ebb344e2585..8ea96d83d599 100644
--- a/block/blk-mq-debugfs.c
+++ b/block/blk-mq-debugfs.c
@@ -973,6 +973,14 @@ void blk_mq_debugfs_register_sched_hctx(struct request_queue *q,
struct elevator_type *e = q->elevator->type;
+ /*
+ * If the parent debugfs directory has not been created yet, return;
+ * We will be called again later on with appropriate parent debugfs
+ * directory from blk_register_queue()
+ */
+ if (!hctx->debugfs_dir)
+ return;
if (!e->hctx_debugfs_attrs)