Commit bfebd1cdb4 ("dm: add full blk-mq support to request-based DM")
didn't properly account for the need to short-circuit re-initializing
DM's blk-mq request_queue if it was already initialized.
Fix dm_init_request_based_blk_mq_queue() to return early if the
mapped_device's tag_set already has its driver_data set to the
mapped_device pointer.
Otherwise, reloading a blk-mq request-based DM table (either manually or
via multipathd) resulted in errors like the following:
WARNING: CPU: 9 PID: 2836 at lib/list_debug.c:36 __list_add+0x92/0xc0()
...
kobject (ffff880035625fd0): tried to init an initialized object, something is seriously wrong.
...
sysfs: cannot create duplicate filename '/devices/virtual/block/dm-13/mq'
...
kobject_add_internal failed for mq with -EEXIST, don't try to register things with the same name in the same directory.
Reported-by: Christoph Hellwig <hch@xxxxxx>
Signed-off-by: Mike Snitzer <snitzer@xxxxxxxxxx>
---
drivers/md/dm.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)
diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index 1567f6c..c834a94 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -2704,6 +2704,9 @@ static int dm_init_request_based_blk_mq_queue(struct mapped_device *md)
struct request_queue *q;
int err;
+ if (md->tag_set.driver_data == md)
+ return 0;
+
memset(&md->tag_set, 0, sizeof(md->tag_set));
md->tag_set.ops = &dm_mq_ops;
md->tag_set.queue_depth = BLKDEV_MAX_RQ;
@@ -2719,7 +2722,7 @@ static int dm_init_request_based_blk_mq_queue(struct mapped_device *md)
err = blk_mq_alloc_tag_set(&md->tag_set);
if (err)
- return err;
+ goto out;
q = blk_mq_init_allocated_queue(&md->tag_set, md->queue);
if (IS_ERR(q)) {
@@ -2739,6 +2742,8 @@ static int dm_init_request_based_blk_mq_queue(struct mapped_device *md)
out_tag_set:
blk_mq_free_tag_set(&md->tag_set);
+out:
+ memset(&md->tag_set, 0, sizeof(md->tag_set));
return err;
}
--
2.3.2 (Apple Git-55)
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