md: add a mddev_is_dm helper

[linux-block.git] / drivers / md / md.h

diff --git a/drivers/md/md.h b/drivers/md/md.h
index e2e1ddd397ea31d36a644f10022c75098c531547..d5e99653c690e91a5c9263b5ca3f377bfb6bf0ea 100644 (file)
--- a/drivers/md/md.h
+++ b/drivers/md/md.h
@@ -911,16 +911,24 @@ int do_md_run(struct mddev *mddev);
 
 extern const struct block_device_operations md_fops;
 
+/*
+ * MD devices can be used undeneath by DM, in which case ->gendisk is NULL.
+ */
+static inline bool mddev_is_dm(struct mddev *mddev)
+{
+       return !mddev->gendisk;
+}
+
 static inline void mddev_trace_remap(struct mddev *mddev, struct bio *bio,
                sector_t sector)
 {
-       if (mddev->gendisk)
+       if (!mddev_is_dm(mddev))
                trace_block_bio_remap(bio, disk_devt(mddev->gendisk), sector);
 }
 
 #define mddev_add_trace_msg(mddev, fmt, args...)                       \
 do {                                                                   \
-       if ((mddev)->gendisk)                                           \
+       if (!mddev_is_dm(mddev))                                        \
                blk_add_trace_msg((mddev)->queue, fmt, ##args);         \
 } while (0)