dm: only initialize the request_queue once
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.
Otherwise, reloading a blk-mq request-based DM table (either manually
or via multipathd) resulted in errors, see:
https://www.redhat.com/archives/dm-devel/2015-April/msg00132.html
Fix is to only initialize the request_queue on the initial table load
(when the mapped_device type is assigned).
This is better than having dm_init_request_based_blk_mq_queue() return
early if the queue was already initialized because it elevates the
constraint to a more meaningful location in DM core. As such the
pre-existing early return in dm_init_request_based_queue() can now be
removed.
Fixes: bfebd1cdb4 ("dm: add full blk-mq support to request-based DM")
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
diff --git a/drivers/md/dm-ioctl.c b/drivers/md/dm-ioctl.c
index c8a18e4..720ceeb 100644
--- a/drivers/md/dm-ioctl.c
+++ b/drivers/md/dm-ioctl.c
@@ -1298,21 +1298,22 @@
goto err_unlock_md_type;
}
- if (dm_get_md_type(md) == DM_TYPE_NONE)
+ if (dm_get_md_type(md) == DM_TYPE_NONE) {
/* Initial table load: acquire type of table. */
dm_set_md_type(md, dm_table_get_type(t));
- else if (dm_get_md_type(md) != dm_table_get_type(t)) {
+
+ /* setup md->queue to reflect md's type (may block) */
+ r = dm_setup_md_queue(md);
+ if (r) {
+ DMWARN("unable to set up device queue for new table.");
+ goto err_unlock_md_type;
+ }
+ } else if (dm_get_md_type(md) != dm_table_get_type(t)) {
DMWARN("can't change device type after initial table load.");
r = -EINVAL;
goto err_unlock_md_type;
}
- /* setup md->queue to reflect md's type (may block) */
- r = dm_setup_md_queue(md);
- if (r) {
- DMWARN("unable to set up device queue for new table.");
- goto err_unlock_md_type;
- }
dm_unlock_md_type(md);
/* stage inactive table */