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authorChristoph Hellwig <hch@lst.de>2022-06-14 09:48:25 +0200
committerJens Axboe <axboe@kernel.dk>2022-06-17 07:31:05 -0600
commit5cf9c91ba927119fc6606b938b1895bb2459d3bc (patch)
treec6d3d7b1806f35e8fff9c439285324c6feeddad5 /block/blk-sysfs.c
parent50e34d78815e474d410f342fbe783b18192ca518 (diff)
downloadlinux-5cf9c91ba927119fc6606b938b1895bb2459d3bc.tar.bz2
block: serialize all debugfs operations using q->debugfs_mutex
Various places like I/O schedulers or the QOS infrastructure try to register debugfs files on demans, which can race with creating and removing the main queue debugfs directory. Use the existing debugfs_mutex to serialize all debugfs operations that rely on q->debugfs_dir or the directories hanging off it. To make the teardown code a little simpler declare all debugfs dentry pointers and not just the main one uncoditionally in blkdev.h. Move debugfs_mutex next to the dentries that it protects and document what it is used for. Signed-off-by: Christoph Hellwig <hch@lst.de> Link: https://lore.kernel.org/r/20220614074827.458955-3-hch@lst.de Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'block/blk-sysfs.c')
-rw-r--r--block/blk-sysfs.c20
1 files changed, 9 insertions, 11 deletions
diff --git a/block/blk-sysfs.c b/block/blk-sysfs.c
index 88bd41d4cb59..6e4801b217a7 100644
--- a/block/blk-sysfs.c
+++ b/block/blk-sysfs.c
@@ -779,14 +779,13 @@ static void blk_release_queue(struct kobject *kobj)
if (queue_is_mq(q))
blk_mq_release(q);
- blk_trace_shutdown(q);
mutex_lock(&q->debugfs_mutex);
+ blk_trace_shutdown(q);
debugfs_remove_recursive(q->debugfs_dir);
+ q->debugfs_dir = NULL;
+ q->sched_debugfs_dir = NULL;
mutex_unlock(&q->debugfs_mutex);
- if (queue_is_mq(q))
- blk_mq_debugfs_unregister(q);
-
bioset_exit(&q->bio_split);
if (blk_queue_has_srcu(q))
@@ -836,17 +835,16 @@ int blk_register_queue(struct gendisk *disk)
goto unlock;
}
+ if (queue_is_mq(q))
+ __blk_mq_register_dev(dev, q);
+ mutex_lock(&q->sysfs_lock);
+
mutex_lock(&q->debugfs_mutex);
q->debugfs_dir = debugfs_create_dir(kobject_name(q->kobj.parent),
blk_debugfs_root);
- mutex_unlock(&q->debugfs_mutex);
-
- if (queue_is_mq(q)) {
- __blk_mq_register_dev(dev, q);
+ if (queue_is_mq(q))
blk_mq_debugfs_register(q);
- }
-
- mutex_lock(&q->sysfs_lock);
+ mutex_unlock(&q->debugfs_mutex);
ret = disk_register_independent_access_ranges(disk, NULL);
if (ret)