1 files changed, 43 insertions, 1 deletions

diff --git a/drivers/md/dm-table.c b/drivers/md/dm-table.c
index 88f01744ac16..ee6f37eafbc3 100644
--- a/drivers/md/dm-table.c
+++ b/drivers/md/dm-table.c
@@ -827,6 +827,12 @@ void dm_consume_args(struct dm_arg_set *as, unsigned num_args)
 }
 EXPORT_SYMBOL(dm_consume_args);
 
+static bool __table_type_bio_based(unsigned table_type)
+{
+	return (table_type == DM_TYPE_BIO_BASED ||
+		table_type == DM_TYPE_DAX_BIO_BASED);
+}
+
 static bool __table_type_request_based(unsigned table_type)
 {
 	return (table_type == DM_TYPE_REQUEST_BASED ||
@@ -839,6 +845,34 @@ void dm_table_set_type(struct dm_table *t, unsigned type)
 }
 EXPORT_SYMBOL_GPL(dm_table_set_type);
 
+static int device_supports_dax(struct dm_target *ti, struct dm_dev *dev,
+			       sector_t start, sector_t len, void *data)
+{
+	struct request_queue *q = bdev_get_queue(dev->bdev);
+
+	return q && blk_queue_dax(q);
+}
+
+static bool dm_table_supports_dax(struct dm_table *t)
+{
+	struct dm_target *ti;
+	unsigned i = 0;
+
+	/* Ensure that all targets support DAX. */
+	while (i < dm_table_get_num_targets(t)) {
+		ti = dm_table_get_target(t, i++);
+
+		if (!ti->type->direct_access)
+			return false;
+
+		if (!ti->type->iterate_devices ||
+		    !ti->type->iterate_devices(ti, device_supports_dax, NULL))
+			return false;
+	}
+
+	return true;
+}
+
 static int dm_table_determine_type(struct dm_table *t)
 {
 	unsigned i;
@@ -853,6 +887,7 @@ static int dm_table_determine_type(struct dm_table *t)
 		/* target already set the table's type */
 		if (t->type == DM_TYPE_BIO_BASED)
 			return 0;
+		BUG_ON(t->type == DM_TYPE_DAX_BIO_BASED);
 		goto verify_rq_based;
 	}
 
@@ -887,6 +922,8 @@ static int dm_table_determine_type(struct dm_table *t)
 	if (bio_based) {
 		/* We must use this table as bio-based */
 		t->type = DM_TYPE_BIO_BASED;
+		if (dm_table_supports_dax(t))
+			t->type = DM_TYPE_DAX_BIO_BASED;
 		return 0;
 	}
 
@@ -979,6 +1016,11 @@ struct dm_target *dm_table_get_wildcard_target(struct dm_table *t)
 	return NULL;
 }
 
+bool dm_table_bio_based(struct dm_table *t)
+{
+	return __table_type_bio_based(dm_table_get_type(t));
+}
+
 bool dm_table_request_based(struct dm_table *t)
 {
 	return __table_type_request_based(dm_table_get_type(t));
@@ -1001,7 +1043,7 @@ static int dm_table_alloc_md_mempools(struct dm_table *t, struct mapped_device *
 		return -EINVAL;
 	}
 
-	if (type == DM_TYPE_BIO_BASED)
+	if (__table_type_bio_based(type))
 		for (i = 0; i < t->num_targets; i++) {
 			tgt = t->targets + i;
 			per_io_data_size = max(per_io_data_size, tgt->per_io_data_size);