md/bitmap: remove dead code from md/bitmap

bitmap_active is never called, and the BITMAP_ACTIVE flag is never users or
tested, so discard them both.

Also remove some out-of-date 'todo' comments.
Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Adrian Bunk <bunk@kernel.org>

drivers/md/bitmap.c

@@ -15,9 +15,6 @@
  *
  * flush after percent set rather than just time based. (maybe both).
  * wait if count gets too high, wake when it drops to half.
- * allow bitmap to be mirrored with superblock (before or after...)
- * allow hot-add to re-instate a current device.
- * allow hot-add of bitmap after quiessing device
  */
 
 #include <linux/module.h>
@@ -71,23 +68,6 @@ static inline char * bmname(struct bitmap *bitmap)
 	return bitmap->mddev ? mdname(bitmap->mddev) : "mdX";
 }
 
-
-/*
- * test if the bitmap is active
- */
-int bitmap_active(struct bitmap *bitmap)
-{
-	unsigned long flags;
-	int res = 0;
-
-	if (!bitmap)
-		return res;
-	spin_lock_irqsave(&bitmap->lock, flags);
-	res = bitmap->flags & BITMAP_ACTIVE;
-	spin_unlock_irqrestore(&bitmap->lock, flags);
-	return res;
-}
-
 #define WRITE_POOL_SIZE 256
 /* mempool for queueing pending writes on the bitmap file */
 static void *write_pool_alloc(gfp_t gfp_flags, void *data)
@@ -1596,8 +1576,6 @@ int bitmap_create(mddev_t *mddev)
 	if (!bitmap->bp)
 		goto error;
 
-	bitmap->flags |= BITMAP_ACTIVE;
-
 	/* now that we have some pages available, initialize the in-memory
 	 * bitmap from the on-disk bitmap */
 	start = 0;

include/linux/raid/bitmap.h

@@ -261,7 +261,6 @@ struct bitmap {
 int  bitmap_create(mddev_t *mddev);
 void bitmap_flush(mddev_t *mddev);
 void bitmap_destroy(mddev_t *mddev);
-int  bitmap_active(struct bitmap *bitmap);
 
 char *file_path(struct file *file, char *buf, int count);
 void bitmap_print_sb(struct bitmap *bitmap);