dm: add 'use_blk_mq' module param and expose in per-device ro sysfs attr
Request-based DM's blk-mq support defaults to off; but a user can easily
change the default using the dm_mod.use_blk_mq module/boot option.
Also, you can check what mode a given request-based DM device is using
with: cat /sys/block/dm-X/dm/use_blk_mq
This change enabled further cleanup and reduced work (e.g. the
md->io_pool and md->rq_pool isn't created if using blk-mq).
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
diff --git a/drivers/md/dm.h b/drivers/md/dm.h
index 5522422..6123c2b 100644
--- a/drivers/md/dm.h
+++ b/drivers/md/dm.h
@@ -211,6 +211,8 @@
void dm_internal_suspend(struct mapped_device *md);
void dm_internal_resume(struct mapped_device *md);
+bool dm_use_blk_mq(struct mapped_device *md);
+
int dm_io_init(void);
void dm_io_exit(void);
@@ -220,7 +222,8 @@
/*
* Mempool operations
*/
-struct dm_md_mempools *dm_alloc_md_mempools(unsigned type, unsigned integrity, unsigned per_bio_data_size);
+struct dm_md_mempools *dm_alloc_md_mempools(struct mapped_device *md, unsigned type,
+ unsigned integrity, unsigned per_bio_data_size);
void dm_free_md_mempools(struct dm_md_mempools *pools);
/*