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, 12 insertions, 34 deletions

diff --git a/drivers/md/dm-table.c b/drivers/md/dm-table.c
index fb4bea20657b..9038c302d5c2 100644
--- a/drivers/md/dm-table.c
+++ b/drivers/md/dm-table.c
@@ -47,7 +47,6 @@ struct dm_table {
 
 	bool integrity_supported:1;
 	bool singleton:1;
-	bool all_blk_mq:1;
 	unsigned integrity_added:1;
 
 	/*
@@ -872,8 +871,7 @@ static bool __table_type_bio_based(enum dm_queue_mode table_type)
 
 static bool __table_type_request_based(enum dm_queue_mode table_type)
 {
-	return (table_type == DM_TYPE_REQUEST_BASED ||
-		table_type == DM_TYPE_MQ_REQUEST_BASED);
+	return table_type == DM_TYPE_REQUEST_BASED;
 }
 
 void dm_table_set_type(struct dm_table *t, enum dm_queue_mode type)
@@ -999,10 +997,6 @@ verify_bio_based:
 
 	BUG_ON(!request_based); /* No targets in this table */
 
-	/*
-	 * The only way to establish DM_TYPE_MQ_REQUEST_BASED is by
-	 * having a compatible target use dm_table_set_type.
-	 */
 	t->type = DM_TYPE_REQUEST_BASED;
 
 verify_rq_based:
@@ -1022,11 +1016,9 @@ verify_rq_based:
 		int srcu_idx;
 		struct dm_table *live_table = dm_get_live_table(t->md, &srcu_idx);
 
-		/* inherit live table's type and all_blk_mq */
-		if (live_table) {
+		/* inherit live table's type */
+		if (live_table)
 			t->type = live_table->type;
-			t->all_blk_mq = live_table->all_blk_mq;
-		}
 		dm_put_live_table(t->md, srcu_idx);
 		return 0;
 	}
@@ -1046,17 +1038,10 @@ verify_rq_based:
 		DMERR("table load rejected: including non-request-stackable devices");
 		return -EINVAL;
 	}
-	if (v.sq_count && v.mq_count) {
+	if (v.sq_count > 0) {
 		DMERR("table load rejected: not all devices are blk-mq request-stackable");
 		return -EINVAL;
 	}
-	t->all_blk_mq = v.mq_count > 0;
-
-	if (!t->all_blk_mq &&
-	    (t->type == DM_TYPE_MQ_REQUEST_BASED || t->type == DM_TYPE_NVME_BIO_BASED)) {
-		DMERR("table load rejected: all devices are not blk-mq request-stackable");
-		return -EINVAL;
-	}
 
 	return 0;
 }
@@ -1105,11 +1090,6 @@ bool dm_table_request_based(struct dm_table *t)
 	return __table_type_request_based(dm_table_get_type(t));
 }
 
-bool dm_table_all_blk_mq_devices(struct dm_table *t)
-{
-	return t->all_blk_mq;
-}
-
 static int dm_table_alloc_md_mempools(struct dm_table *t, struct mapped_device *md)
 {
 	enum dm_queue_mode type = dm_table_get_type(t);
@@ -2089,26 +2069,24 @@ struct mapped_device *dm_table_get_md(struct dm_table *t)
 }
 EXPORT_SYMBOL(dm_table_get_md);
 
+const char *dm_table_device_name(struct dm_table *t)
+{
+	return dm_device_name(t->md);
+}
+EXPORT_SYMBOL_GPL(dm_table_device_name);
+
 void dm_table_run_md_queue_async(struct dm_table *t)
 {
 	struct mapped_device *md;
 	struct request_queue *queue;
-	unsigned long flags;
 
 	if (!dm_table_request_based(t))
 		return;
 
 	md = dm_table_get_md(t);
 	queue = dm_get_md_queue(md);
-	if (queue) {
-		if (queue->mq_ops)
-			blk_mq_run_hw_queues(queue, true);
-		else {
-			spin_lock_irqsave(queue->queue_lock, flags);
-			blk_run_queue_async(queue);
-			spin_unlock_irqrestore(queue->queue_lock, flags);
-		}
-	}
+	if (queue)
+		blk_mq_run_hw_queues(queue, true);
 }
 EXPORT_SYMBOL(dm_table_run_md_queue_async);