dm-raid: do not include dm-core.h

In commit 4cc9613 ("dm: move request-based code out to dm-rq.[hc]")
we have a note: "DM targets should _never_ include dm-core.h!". And it
is not used in any DM targets except dm-raid now, so let's remove it
from dm-raid for consistency, also use special helpers instead of
accessing dm_table and mapper_device fields directly. This change is
merely a cleanup and should not affect functionality.

Signed-off-by: Pavel Tikhomirov <[email protected]>
Reviewed-by: Yu Kuai <[email protected]>
Signed-off-by: Mikulas Patocka <[email protected]>

Author: Snorch

drivers/md/dm-raid.c

@@ -14,7 +14,6 @@
 #include "raid5.h"
 #include "raid10.h"
 #include "md-bitmap.h"
-#include "dm-core.h"
 
 #include <linux/device-mapper.h>
 
@@ -3309,7 +3308,7 @@ static int raid_ctr(struct dm_target *ti, unsigned int argc, char **argv)
 
 	/* Disable/enable discard support on raid set. */
 	configure_discard_support(rs);
-	rs->md.dm_gendisk = ti->table->md->disk;
+	rs->md.dm_gendisk = dm_disk(dm_table_get_md(ti->table));
 
 	mddev_unlock(&rs->md);
 	return 0;