Merge tag 'for-4.20/dm-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm

Pull device mapper updates from Mike Snitzer:

 - The biggest change this cycle is to remove support for the legacy IO
   path (.request_fn) from request-based DM.

   Jens has already started preparing for complete removal of the legacy
   IO path in 4.21 but this earlier removal of support from DM has been
   coordinated with Jens (as evidenced by the commit being attributed to
   him).

   Making request-based DM exclussively blk-mq only cleans up that
   portion of DM core quite nicely.

 - Convert the thinp and zoned targets over to using refcount_t where
   applicable.

 - A couple fixes to the DM zoned target for refcounting and other races
   buried in the implementation of metadata block creation and use.

 - Small cleanups to remove redundant unlikely() around a couple
   WARN_ON_ONCE().

 - Simplify how dm-ioctl copies from userspace, eliminating some
   potential for a malicious user trying to change the executed ioctl
   after its processing has begun.

 - Tweaked DM crypt target to use the DM device name when naming the
   various workqueues created for a particular DM crypt device (makes
   the N workqueues for a DM crypt device more easily understood and
   enhances user's accounting capabilities at a glance via "ps")

 - Small fixup to remove dead branch in DM writecache's memory_entry().

* tag 'for-4.20/dm-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm:
  dm writecache: remove disabled code in memory_entry()
  dm zoned: fix various dmz_get_mblock() issues
  dm zoned: fix metadata block ref counting
  dm raid: avoid bitmap with raid4/5/6 journal device
  dm crypt: make workqueue names device-specific
  dm: add dm_table_device_name()
  dm ioctl: harden copy_params()'s copy_from_user() from malicious users
  dm: remove unnecessary unlikely() around WARN_ON_ONCE()
  dm zoned: target: use refcount_t for dm zoned reference counters
  dm thin: use refcount_t for thin_c reference counting
  dm table: require that request-based DM be layered on blk-mq devices
  dm: rename DM_TYPE_MQ_REQUEST_BASED to DM_TYPE_REQUEST_BASED
  dm: remove legacy request-based IO path

1 files changed, 2 insertions, 23 deletions

diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index 6be21dc210a1..c510179a7f84 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -1664,7 +1664,7 @@ static blk_qc_t __process_bio(struct mapped_device *md,
 		 * Defend against IO still getting in during teardown
 		 * - as was seen for a time with nvme-fcloop
 		 */
-		if (unlikely(WARN_ON_ONCE(!ti || !dm_target_is_valid(ti)))) {
+		if (WARN_ON_ONCE(!ti || !dm_target_is_valid(ti))) {
 			error = -EIO;
 			goto out;
 		}
@@ -1806,8 +1806,6 @@ static void dm_wq_work(struct work_struct *work);
 
 static void dm_init_normal_md_queue(struct mapped_device *md)
 {
-	md->use_blk_mq = false;
-
 	/*
 	 * Initialize aspects of queue that aren't relevant for blk-mq
 	 */
@@ -1818,8 +1816,6 @@ static void cleanup_mapped_device(struct mapped_device *md)
 {
 	if (md->wq)
 		destroy_workqueue(md->wq);
-	if (md->kworker_task)
-		kthread_stop(md->kworker_task);
 	bioset_exit(&md->bs);
 	bioset_exit(&md->io_bs);
 
@@ -1886,7 +1882,6 @@ static struct mapped_device *alloc_dev(int minor)
 		goto bad_io_barrier;
 
 	md->numa_node_id = numa_node_id;
-	md->use_blk_mq = dm_use_blk_mq_default();
 	md->init_tio_pdu = false;
 	md->type = DM_TYPE_NONE;
 	mutex_init(&md->suspend_lock);
@@ -1917,7 +1912,6 @@ static struct mapped_device *alloc_dev(int minor)
 	INIT_WORK(&md->work, dm_wq_work);
 	init_waitqueue_head(&md->eventq);
 	init_completion(&md->kobj_holder.completion);
-	md->kworker_task = NULL;
 
 	md->disk->major = _major;
 	md->disk->first_minor = minor;
@@ -2217,14 +2211,6 @@ int dm_setup_md_queue(struct mapped_device *md, struct dm_table *t)
 
 	switch (type) {
 	case DM_TYPE_REQUEST_BASED:
-		dm_init_normal_md_queue(md);
-		r = dm_old_init_request_queue(md, t);
-		if (r) {
-			DMERR("Cannot initialize queue for request-based mapped device");
-			return r;
-		}
-		break;
-	case DM_TYPE_MQ_REQUEST_BASED:
 		r = dm_mq_init_request_queue(md, t);
 		if (r) {
 			DMERR("Cannot initialize queue for request-based dm-mq mapped device");
@@ -2329,9 +2315,6 @@ static void __dm_destroy(struct mapped_device *md, bool wait)
 
 	blk_set_queue_dying(md->queue);
 
-	if (dm_request_based(md) && md->kworker_task)
-		kthread_flush_worker(&md->kworker);
-
 	/*
 	 * Take suspend_lock so that presuspend and postsuspend methods
 	 * do not race with internal suspend.
@@ -2584,11 +2567,8 @@ static int __dm_suspend(struct mapped_device *md, struct dm_table *map,
 	 * Stop md->queue before flushing md->wq in case request-based
 	 * dm defers requests to md->wq from md->queue.
 	 */
-	if (dm_request_based(md)) {
+	if (dm_request_based(md))
 		dm_stop_queue(md->queue);
-		if (md->kworker_task)
-			kthread_flush_worker(&md->kworker);
-	}
 
 	flush_workqueue(md->wq);
 
@@ -2963,7 +2943,6 @@ struct dm_md_mempools *dm_alloc_md_mempools(struct mapped_device *md, enum dm_qu
 			goto out;
 		break;
 	case DM_TYPE_REQUEST_BASED:
-	case DM_TYPE_MQ_REQUEST_BASED:
 		pool_size = max(dm_get_reserved_rq_based_ios(), min_pool_size);
 		front_pad = offsetof(struct dm_rq_clone_bio_info, clone);
 		/* per_io_data_size is used for blk-mq pdu at queue allocation */