[PATCH 4.9 07/11] dm table: fix DAX iterate_devices based device capability checks

[gregkh]

From: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

From: Jeffle Xu <jefflexu@xxxxxxxxxxxxxxxxx>

commit 5b0fab508992c2e120971da658ce80027acbc405 upstream.

Fix dm_table_supports_dax() and invert logic of both
iterate_devices_callout_fn so that all devices' DAX capabilities are
properly checked.

Fixes: 545ed20e6df6 ("dm: add infrastructure for DAX support")
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Jeffle Xu <jefflexu@xxxxxxxxxxxxxxxxx>
Signed-off-by: Mike Snitzer <snitzer@xxxxxxxxxx>
[jeffle: no dax write cache, no dax synchronous]
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 drivers/md/dm-table.c |    8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

--- a/drivers/md/dm-table.c
+++ b/drivers/md/dm-table.c
@@ -848,12 +848,12 @@ void dm_table_set_type(struct dm_table *
 }
 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)
+static int device_not_dax_capable(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);
+	return q && !blk_queue_dax(q);
 }
 
 static bool dm_table_supports_dax(struct dm_table *t)
@@ -869,7 +869,7 @@ static bool dm_table_supports_dax(struct
 			return false;
 
 		if (!ti->type->iterate_devices ||
-		    !ti->type->iterate_devices(ti, device_supports_dax, NULL))
+		    ti->type->iterate_devices(ti, device_not_dax_capable, NULL))
 			return false;
 	}