MD RAID10: Prep for DM RAID10 device replacement capability

MD RAID10:  Fix a couple potential kernel panics if RAID10 is used by dm-raid

When device-mapper uses the RAID10 personality through dm-raid.c, there is no
'gendisk' structure in mddev and some sysfs information is also not populated.

This patch avoids touching those non-existent structures.

Signed-off-by: Jonathan Brassow <jbrassow@rehdat.com>
Signed-off-by: NeilBrown <neilb@suse.de>
diff --git a/drivers/md/md.c b/drivers/md/md.c
index feab588..85e6786 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -2044,8 +2044,14 @@
 /* Disable data integrity if non-capable/non-matching disk is being added */
 void md_integrity_add_rdev(struct md_rdev *rdev, struct mddev *mddev)
 {
-	struct blk_integrity *bi_rdev = bdev_get_integrity(rdev->bdev);
-	struct blk_integrity *bi_mddev = blk_get_integrity(mddev->gendisk);
+	struct blk_integrity *bi_rdev;
+	struct blk_integrity *bi_mddev;
+
+	if (!mddev->gendisk)
+		return;
+
+	bi_rdev = bdev_get_integrity(rdev->bdev);
+	bi_mddev = blk_get_integrity(mddev->gendisk);
 
 	if (!bi_mddev) /* nothing to do */
 		return;
diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c
index 5486060..fb5bd60 100644
--- a/drivers/md/raid10.c
+++ b/drivers/md/raid10.c
@@ -1694,7 +1694,7 @@
 			   && !test_bit(Faulty, &tmp->rdev->flags)
 			   && !test_and_set_bit(In_sync, &tmp->rdev->flags)) {
 			count++;
-			sysfs_notify_dirent(tmp->rdev->sysfs_state);
+			sysfs_notify_dirent_safe(tmp->rdev->sysfs_state);
 		}
 	}
 	spin_lock_irqsave(&conf->device_lock, flags);