Merge branch 'md-6.12-bitmap' into md-6.12

From Yu Kuai (with minor changes by Song Liu):

The background is that currently bitmap is using a global spin_lock,
causing lock contention and huge IO performance degradation for all raid
levels.

However, it's impossible to implement a new lock free bitmap with
current situation that md-bitmap exposes the internal implementation
with lots of exported apis. Hence bitmap_operations is invented, to
describe bitmap core implementation, and a new bitmap can be introduced
with a new bitmap_operations, we only need to switch to the new one
during initialization.

And with this we can build bitmap as kernel module, but that's not
our concern for now.

This version was tested with mdadm tests and lvm2 tests. This set does
not introduce new errors in these tests.

* md-6.12-bitmap: (42 commits)
  md/md-bitmap: make in memory structure internal
  md/md-bitmap: merge md_bitmap_enabled() into bitmap_operations
  md/md-bitmap: merge md_bitmap_wait_behind_writes() into bitmap_operations
  md/md-bitmap: merge md_bitmap_free() into bitmap_operations
  md/md-bitmap: merge md_bitmap_set_pages() into struct bitmap_operations
  md/md-bitmap: merge md_bitmap_copy_from_slot() into struct bitmap_operation.
  md/md-bitmap: merge get_bitmap_from_slot() into bitmap_operations
  md/md-bitmap: merge md_bitmap_resize() into bitmap_operations
  md/md-bitmap: pass in mddev directly for md_bitmap_resize()
  md/md-bitmap: merge md_bitmap_daemon_work() into bitmap_operations
  md/md-bitmap: merge bitmap_unplug() into bitmap_operations
  md/md-bitmap: merge md_bitmap_unplug_async() into md_bitmap_unplug()
  md/md-bitmap: merge md_bitmap_sync_with_cluster() into bitmap_operations
  md/md-bitmap: merge md_bitmap_cond_end_sync() into bitmap_operations
  md/md-bitmap: merge md_bitmap_close_sync() into bitmap_operations
  md/md-bitmap: merge md_bitmap_end_sync() into bitmap_operations
  md/md-bitmap: remove the parameter 'aborted' for md_bitmap_end_sync()
  md/md-bitmap: merge md_bitmap_start_sync() into bitmap_operations
  md/md-bitmap: merge md_bitmap_endwrite() into bitmap_operations
  md/md-bitmap: merge md_bitmap_startwrite() into bitmap_operations
  ...
Signed-off-by: Song Liu <song@kernel.org>

drivers/md/dm-raid.c

@@ -3949,7 +3949,9 @@ static int __load_dirty_region_bitmap(struct raid_set *rs)
 	/* Try loading the bitmap unless "raid0", which does not have one */
 	if (!rs_is_raid0(rs) &&
 	    !test_and_set_bit(RT_FLAG_RS_BITMAP_LOADED, &rs->runtime_flags)) {
-		r = md_bitmap_load(&rs->md);
+		struct mddev *mddev = &rs->md;
+
+		r = mddev->bitmap_ops->load(mddev);
 		if (r)
 			DMERR("Failed to load bitmap");
 	}
@@ -4066,7 +4068,8 @@ static int raid_preresume(struct dm_target *ti)
 	       mddev->bitmap_info.chunksize != to_bytes(rs->requested_bitmap_chunk_sectors)))) {
 		int chunksize = to_bytes(rs->requested_bitmap_chunk_sectors) ?: mddev->bitmap_info.chunksize;
 
-		r = md_bitmap_resize(mddev->bitmap, mddev->dev_sectors, chunksize, 0);
+		r = mddev->bitmap_ops->resize(mddev, mddev->dev_sectors,
+					      chunksize, false);
 		if (r)
 			DMERR("Failed to resize bitmap");
 	}

drivers/md/md-cluster.c

@@ -317,7 +317,7 @@ static void recover_bitmaps(struct md_thread *thread)
 					str, ret);
 			goto clear_bit;
 		}
-		ret = md_bitmap_copy_from_slot(mddev, slot, &lo, &hi, true);
+		ret = mddev->bitmap_ops->copy_from_slot(mddev, slot, &lo, &hi, true);
 		if (ret) {
 			pr_err("md-cluster: Could not copy data from bitmap %d\n", slot);
 			goto clear_bit;
@@ -497,7 +497,7 @@ static void process_suspend_info(struct mddev *mddev,
 	 * we don't want to trigger lots of WARN.
 	 */
 	if (sb && !(le32_to_cpu(sb->feature_map) & MD_FEATURE_RESHAPE_ACTIVE))
-		md_bitmap_sync_with_cluster(mddev, cinfo->sync_low,
+		mddev->bitmap_ops->sync_with_cluster(mddev, cinfo->sync_low,
 						     cinfo->sync_hi, lo, hi);
 	cinfo->sync_low = lo;
 	cinfo->sync_hi = hi;
@@ -628,8 +628,9 @@ static int process_recvd_msg(struct mddev *mddev, struct cluster_msg *msg)
 		break;
 	case BITMAP_RESIZE:
 		if (le64_to_cpu(msg->high) != mddev->pers->size(mddev, 0, 0))
-			ret = md_bitmap_resize(mddev->bitmap,
-					    le64_to_cpu(msg->high), 0, 0);
+			ret = mddev->bitmap_ops->resize(mddev,
+							le64_to_cpu(msg->high),
+							0, false);
 		break;
 	default:
 		ret = -1;
@@ -856,7 +857,7 @@ static int gather_all_resync_info(struct mddev *mddev, int total_slots)
 		}
 
 		/* Read the disk bitmap sb and check if it needs recovery */
-		ret = md_bitmap_copy_from_slot(mddev, i, &lo, &hi, false);
+		ret = mddev->bitmap_ops->copy_from_slot(mddev, i, &lo, &hi, false);
 		if (ret) {
 			pr_warn("md-cluster: Could not gather bitmaps from slot %d", i);
 			lockres_free(bm_lockres);
@@ -1143,13 +1144,16 @@ static int update_bitmap_size(struct mddev *mddev, sector_t size)
 
 static int resize_bitmaps(struct mddev *mddev, sector_t newsize, sector_t oldsize)
 {
-	struct bitmap_counts *counts;
-	char str[64];
-	struct dlm_lock_resource *bm_lockres;
-	struct bitmap *bitmap = mddev->bitmap;
-	unsigned long my_pages = bitmap->counts.pages;
+	void *bitmap = mddev->bitmap;
+	struct md_bitmap_stats stats;
+	unsigned long my_pages;
 	int i, rv;
 
+	rv = mddev->bitmap_ops->get_stats(bitmap, &stats);
+	if (rv)
+		return rv;
+
+	my_pages = stats.pages;
 	/*
 	 * We need to ensure all the nodes can grow to a larger
 	 * bitmap size before make the reshaping.
@@ -1159,17 +1163,22 @@ static int resize_bitmaps(struct mddev *mddev, sector_t newsize, sector_t oldsiz
 		return rv;
 
 	for (i = 0; i < mddev->bitmap_info.nodes; i++) {
+		struct dlm_lock_resource *bm_lockres;
+		char str[64];
+
 		if (i == md_cluster_ops->slot_number(mddev))
 			continue;
 
-		bitmap = get_bitmap_from_slot(mddev, i);
+		bitmap = mddev->bitmap_ops->get_from_slot(mddev, i);
 		if (IS_ERR(bitmap)) {
 			pr_err("can't get bitmap from slot %d\n", i);
 			bitmap = NULL;
 			goto out;
 		}
-		counts = &bitmap->counts;
 
+		rv = mddev->bitmap_ops->get_stats(bitmap, &stats);
+		if (rv)
+			goto out;
 		/*
 		 * If we can hold the bitmap lock of one node then
 		 * the slot is not occupied, update the pages.
@@ -1183,21 +1192,21 @@ static int resize_bitmaps(struct mddev *mddev, sector_t newsize, sector_t oldsiz
 		bm_lockres->flags |= DLM_LKF_NOQUEUE;
 		rv = dlm_lock_sync(bm_lockres, DLM_LOCK_PW);
 		if (!rv)
-			counts->pages = my_pages;
+			mddev->bitmap_ops->set_pages(bitmap, my_pages);
 		lockres_free(bm_lockres);
 
-		if (my_pages != counts->pages)
+		if (my_pages != stats.pages)
 			/*
 			 * Let's revert the bitmap size if one node
 			 * can't resize bitmap
 			 */
 			goto out;
-		md_bitmap_free(bitmap);
+		mddev->bitmap_ops->free(bitmap);
 	}
 
 	return 0;
 out:
-	md_bitmap_free(bitmap);
+	mddev->bitmap_ops->free(bitmap);
 	update_bitmap_size(mddev, oldsize);
 	return -1;
 }
@@ -1207,24 +1216,27 @@ static int resize_bitmaps(struct mddev *mddev, sector_t newsize, sector_t oldsiz
  */
 static int cluster_check_sync_size(struct mddev *mddev)
 {
-	int i, rv;
-	bitmap_super_t *sb;
-	unsigned long my_sync_size, sync_size = 0;
-	int node_num = mddev->bitmap_info.nodes;
 	int current_slot = md_cluster_ops->slot_number(mddev);
-	struct bitmap *bitmap = mddev->bitmap;
-	char str[64];
+	int node_num = mddev->bitmap_info.nodes;
 	struct dlm_lock_resource *bm_lockres;
+	struct md_bitmap_stats stats;
+	void *bitmap = mddev->bitmap;
+	unsigned long sync_size = 0;
+	unsigned long my_sync_size;
+	char str[64];
+	int i, rv;
 
-	sb = kmap_atomic(bitmap->storage.sb_page);
-	my_sync_size = sb->sync_size;
-	kunmap_atomic(sb);
+	rv = mddev->bitmap_ops->get_stats(bitmap, &stats);
+	if (rv)
+		return rv;
+
+	my_sync_size = stats.sync_size;
 
 	for (i = 0; i < node_num; i++) {
 		if (i == current_slot)
 			continue;
 
-		bitmap = get_bitmap_from_slot(mddev, i);
+		bitmap = mddev->bitmap_ops->get_from_slot(mddev, i);
 		if (IS_ERR(bitmap)) {
 			pr_err("can't get bitmap from slot %d\n", i);
 			return -1;
@@ -1238,25 +1250,28 @@ static int cluster_check_sync_size(struct mddev *mddev)
 		bm_lockres = lockres_init(mddev, str, NULL, 1);
 		if (!bm_lockres) {
 			pr_err("md-cluster: Cannot initialize %s\n", str);
-			md_bitmap_free(bitmap);
+			mddev->bitmap_ops->free(bitmap);
 			return -1;
 		}
 		bm_lockres->flags |= DLM_LKF_NOQUEUE;
 		rv = dlm_lock_sync(bm_lockres, DLM_LOCK_PW);
 		if (!rv)
-			md_bitmap_update_sb(bitmap);
+			mddev->bitmap_ops->update_sb(bitmap);
 		lockres_free(bm_lockres);
 
-		sb = kmap_atomic(bitmap->storage.sb_page);
-		if (sync_size == 0)
-			sync_size = sb->sync_size;
-		else if (sync_size != sb->sync_size) {
-			kunmap_atomic(sb);
-			md_bitmap_free(bitmap);
+		rv = mddev->bitmap_ops->get_stats(bitmap, &stats);
+		if (rv) {
+			mddev->bitmap_ops->free(bitmap);
+			return rv;
+		}
+
+		if (sync_size == 0) {
+			sync_size = stats.sync_size;
+		} else if (sync_size != stats.sync_size) {
+			mddev->bitmap_ops->free(bitmap);
 			return -1;
 		}
-		kunmap_atomic(sb);
-		md_bitmap_free(bitmap);
+		mddev->bitmap_ops->free(bitmap);
 	}
 
 	return (my_sync_size == sync_size) ? 0 : -1;
@@ -1585,7 +1600,7 @@ static int gather_bitmaps(struct md_rdev *rdev)
 	for (sn = 0; sn < mddev->bitmap_info.nodes; sn++) {
 		if (sn == (cinfo->slot_number - 1))
 			continue;
-		err = md_bitmap_copy_from_slot(mddev, sn, &lo, &hi, false);
+		err = mddev->bitmap_ops->copy_from_slot(mddev, sn, &lo, &hi, false);
 		if (err) {
 			pr_warn("md-cluster: Could not gather bitmaps from slot %d", sn);
 			goto out;

drivers/md/md.c

@@ -664,6 +664,7 @@ int mddev_init(struct mddev *mddev)
 	mddev->resync_min = 0;
 	mddev->resync_max = MaxSector;
 	mddev->level = LEVEL_NONE;
+	mddev_set_bitmap_ops(mddev);
 
 	INIT_WORK(&mddev->sync_work, md_start_sync);
 	INIT_WORK(&mddev->del_work, mddev_delayed_delete);
@@ -1264,6 +1265,18 @@ static int super_90_load(struct md_rdev *rdev, struct md_rdev *refdev, int minor
 	return ret;
 }
 
+static u64 md_bitmap_events_cleared(struct mddev *mddev)
+{
+	struct md_bitmap_stats stats;
+	int err;
+
+	err = mddev->bitmap_ops->get_stats(mddev->bitmap, &stats);
+	if (err)
+		return 0;
+
+	return stats.events_cleared;
+}
+
 /*
  * validate_super for 0.90.0
  * note: we are not using "freshest" for 0.9 superblock
@@ -1356,7 +1369,7 @@ static int super_90_validate(struct mddev *mddev, struct md_rdev *freshest, stru
 		/* if adding to array with a bitmap, then we can accept an
 		 * older device ... but not too old.
 		 */
-		if (ev1 < mddev->bitmap->events_cleared)
+		if (ev1 < md_bitmap_events_cleared(mddev))
 			return 0;
 		if (ev1 < mddev->events)
 			set_bit(Bitmap_sync, &rdev->flags);
@@ -1883,7 +1896,7 @@ static int super_1_validate(struct mddev *mddev, struct md_rdev *freshest, struc
 		/* If adding to array with a bitmap, then we can accept an
 		 * older device, but not too old.
 		 */
-		if (ev1 < mddev->bitmap->events_cleared)
+		if (ev1 < md_bitmap_events_cleared(mddev))
 			return 0;
 		if (ev1 < mddev->events)
 			set_bit(Bitmap_sync, &rdev->flags);
@@ -2215,7 +2228,6 @@ super_1_allow_new_offset(struct md_rdev *rdev,
 			 unsigned long long new_offset)
 {
 	/* All necessary checks on new >= old have been done */
-	struct bitmap *bitmap;
 	if (new_offset >= rdev->data_offset)
 		return 1;
 
@@ -2232,11 +2244,18 @@ super_1_allow_new_offset(struct md_rdev *rdev,
 	 */
 	if (rdev->sb_start + (32+4)*2 > new_offset)
 		return 0;
-	bitmap = rdev->mddev->bitmap;
-	if (bitmap && !rdev->mddev->bitmap_info.file &&
-	    rdev->sb_start + rdev->mddev->bitmap_info.offset +
-	    bitmap->storage.file_pages * (PAGE_SIZE>>9) > new_offset)
+
+	if (!rdev->mddev->bitmap_info.file) {
+		struct mddev *mddev = rdev->mddev;
+		struct md_bitmap_stats stats;
+		int err;
+
+		err = mddev->bitmap_ops->get_stats(mddev->bitmap, &stats);
+		if (!err && rdev->sb_start + mddev->bitmap_info.offset +
+		    stats.file_pages * (PAGE_SIZE >> 9) > new_offset)
 			return 0;
+	}
+
 	if (rdev->badblocks.sector + rdev->badblocks.size > new_offset)
 		return 0;
 
@@ -2712,7 +2731,7 @@ void md_update_sb(struct mddev *mddev, int force_change)
 
 	mddev_add_trace_msg(mddev, "md md_update_sb");
 rewrite:
-	md_bitmap_update_sb(mddev->bitmap);
+	mddev->bitmap_ops->update_sb(mddev->bitmap);
 	rdev_for_each(rdev, mddev) {
 		if (rdev->sb_loaded != 1)
 			continue; /* no noise on spare devices */
@@ -4572,17 +4591,23 @@ bitmap_store(struct mddev *mddev, const char *buf, size_t len)
 	/* buf should be <chunk> <chunk> ... or <chunk>-<chunk> ... (range) */
 	while (*buf) {
 		chunk = end_chunk = simple_strtoul(buf, &end, 0);
-		if (buf == end) break;
+		if (buf == end)
+			break;
+
 		if (*end == '-') { /* range */
 			buf = end + 1;
 			end_chunk = simple_strtoul(buf, &end, 0);
-			if (buf == end) break;
+			if (buf == end)
+				break;
 		}
-		if (*end && !isspace(*end)) break;
-		md_bitmap_dirty_bits(mddev->bitmap, chunk, end_chunk);
+
+		if (*end && !isspace(*end))
+			break;
+
+		mddev->bitmap_ops->dirty_bits(mddev, chunk, end_chunk);
 		buf = skip_spaces(end);
 	}
-	md_bitmap_unplug(mddev->bitmap); /* flush the bits to disk */
+	mddev->bitmap_ops->unplug(mddev, true); /* flush the bits to disk */
 out:
 	mddev_unlock(mddev);
 	return len;
@@ -6098,16 +6123,10 @@ int md_run(struct mddev *mddev)
 	}
 	if (err == 0 && pers->sync_request &&
 	    (mddev->bitmap_info.file || mddev->bitmap_info.offset)) {
-		struct bitmap *bitmap;
-
-		bitmap = md_bitmap_create(mddev, -1);
-		if (IS_ERR(bitmap)) {
-			err = PTR_ERR(bitmap);
+		err = mddev->bitmap_ops->create(mddev, -1);
+		if (err)
 			pr_warn("%s: failed to create bitmap (%d)\n",
 				mdname(mddev), err);
-		} else
-			mddev->bitmap = bitmap;
-
 	}
 	if (err)
 		goto bitmap_abort;
@@ -6177,7 +6196,7 @@ int md_run(struct mddev *mddev)
 		pers->free(mddev, mddev->private);
 	mddev->private = NULL;
 	module_put(pers->owner);
-	md_bitmap_destroy(mddev);
+	mddev->bitmap_ops->destroy(mddev);
 abort:
 	bioset_exit(&mddev->io_clone_set);
 exit_sync_set:
@@ -6196,9 +6215,10 @@ int do_md_run(struct mddev *mddev)
 	err = md_run(mddev);
 	if (err)
 		goto out;
-	err = md_bitmap_load(mddev);
+
+	err = mddev->bitmap_ops->load(mddev);
 	if (err) {
-		md_bitmap_destroy(mddev);
+		mddev->bitmap_ops->destroy(mddev);
 		goto out;
 	}
 
@@ -6342,7 +6362,8 @@ static void __md_stop_writes(struct mddev *mddev)
 		mddev->pers->quiesce(mddev, 1);
 		mddev->pers->quiesce(mddev, 0);
 	}
-	md_bitmap_flush(mddev);
+
+	mddev->bitmap_ops->flush(mddev);
 
 	if (md_is_rdwr(mddev) &&
 	    ((!mddev->in_sync && !mddev_is_clustered(mddev)) ||
@@ -6369,7 +6390,7 @@ EXPORT_SYMBOL_GPL(md_stop_writes);
 
 static void mddev_detach(struct mddev *mddev)
 {
-	md_bitmap_wait_behind_writes(mddev);
+	mddev->bitmap_ops->wait_behind_writes(mddev);
 	if (mddev->pers && mddev->pers->quiesce && !is_md_suspended(mddev)) {
 		mddev->pers->quiesce(mddev, 1);
 		mddev->pers->quiesce(mddev, 0);
@@ -6384,7 +6405,8 @@ static void mddev_detach(struct mddev *mddev)
 static void __md_stop(struct mddev *mddev)
 {
 	struct md_personality *pers = mddev->pers;
-	md_bitmap_destroy(mddev);
+
+	mddev->bitmap_ops->destroy(mddev);
 	mddev_detach(mddev);
 	spin_lock(&mddev->lock);
 	mddev->pers = NULL;
@@ -7162,22 +7184,19 @@ static int set_bitmap_file(struct mddev *mddev, int fd)
 	err = 0;
 	if (mddev->pers) {
 		if (fd >= 0) {
-			struct bitmap *bitmap;
+			err = mddev->bitmap_ops->create(mddev, -1);
+			if (!err)
+				err = mddev->bitmap_ops->load(mddev);
 
-			bitmap = md_bitmap_create(mddev, -1);
-			if (!IS_ERR(bitmap)) {
-				mddev->bitmap = bitmap;
-				err = md_bitmap_load(mddev);
-			} else
-				err = PTR_ERR(bitmap);
 			if (err) {
-				md_bitmap_destroy(mddev);
+				mddev->bitmap_ops->destroy(mddev);
 				fd = -1;
 			}
 		} else if (fd < 0) {
-			md_bitmap_destroy(mddev);
+			mddev->bitmap_ops->destroy(mddev);
 		}
 	}
+
 	if (fd < 0) {
 		struct file *f = mddev->bitmap_info.file;
 		if (f) {
@@ -7446,7 +7465,6 @@ static int update_array_info(struct mddev *mddev, mdu_array_info_t *info)
 			goto err;
 		}
 		if (info->state & (1<<MD_SB_BITMAP_PRESENT)) {
-			struct bitmap *bitmap;
 			/* add the bitmap */
 			if (mddev->bitmap) {
 				rv = -EEXIST;
@@ -7460,24 +7478,24 @@ static int update_array_info(struct mddev *mddev, mdu_array_info_t *info)
 				mddev->bitmap_info.default_offset;
 			mddev->bitmap_info.space =
 				mddev->bitmap_info.default_space;
-			bitmap = md_bitmap_create(mddev, -1);
-			if (!IS_ERR(bitmap)) {
-				mddev->bitmap = bitmap;
-				rv = md_bitmap_load(mddev);
-			} else
-				rv = PTR_ERR(bitmap);
+			rv = mddev->bitmap_ops->create(mddev, -1);
+			if (!rv)
+				rv = mddev->bitmap_ops->load(mddev);
+
 			if (rv)
-				md_bitmap_destroy(mddev);
+				mddev->bitmap_ops->destroy(mddev);
 		} else {
-			/* remove the bitmap */
-			if (!mddev->bitmap) {
-				rv = -ENOENT;
+			struct md_bitmap_stats stats;
+
+			rv = mddev->bitmap_ops->get_stats(mddev->bitmap, &stats);
+			if (rv)
 				goto err;
-			}
-			if (mddev->bitmap->storage.file) {
+
+			if (stats.file) {
 				rv = -EINVAL;
 				goto err;
 			}
+
 			if (mddev->bitmap_info.nodes) {
 				/* hold PW on all the bitmap lock */
 				if (md_cluster_ops->lock_all_bitmaps(mddev) <= 0) {
@@ -7492,7 +7510,7 @@ static int update_array_info(struct mddev *mddev, mdu_array_info_t *info)
 				module_put(md_cluster_mod);
 				mddev->safemode_delay = DEFAULT_SAFEMODE_DELAY;
 			}
-			md_bitmap_destroy(mddev);
+			mddev->bitmap_ops->destroy(mddev);
 			mddev->bitmap_info.offset = 0;
 		}
 	}
@@ -8262,6 +8280,33 @@ static void md_seq_stop(struct seq_file *seq, void *v)
 	spin_unlock(&all_mddevs_lock);
 }
 
+static void md_bitmap_status(struct seq_file *seq, struct mddev *mddev)
+{
+	struct md_bitmap_stats stats;
+	unsigned long used_pages;
+	unsigned long chunk_kb;
+	int err;
+
+	err = mddev->bitmap_ops->get_stats(mddev->bitmap, &stats);
+	if (err)
+		return;
+
+	chunk_kb = mddev->bitmap_info.chunksize >> 10;
+	used_pages = stats.pages - stats.missing_pages;
+
+	seq_printf(seq, "bitmap: %lu/%lu pages [%luKB], %lu%s chunk",
+		   used_pages, stats.pages, used_pages << (PAGE_SHIFT - 10),
+		   chunk_kb ? chunk_kb : mddev->bitmap_info.chunksize,
+		   chunk_kb ? "KB" : "B");
+
+	if (stats.file) {
+		seq_puts(seq, ", file: ");
+		seq_file_path(seq, stats.file, " \t\n");
+	}
+
+	seq_putc(seq, '\n');
+}
+
 static int md_seq_show(struct seq_file *seq, void *v)
 {
 	struct mddev *mddev;
@@ -8345,7 +8390,7 @@ static int md_seq_show(struct seq_file *seq, void *v)
 		} else
 			seq_printf(seq, "\n       ");
 
-		md_bitmap_status(seq, mddev->bitmap);
+		md_bitmap_status(seq, mddev);
 
 		seq_printf(seq, "\n");
 	}
@@ -9397,7 +9442,7 @@ static void md_start_sync(struct work_struct *ws)
 	 * stored on all devices. So make sure all bitmap pages get written.
 	 */
 	if (spares)
-		md_bitmap_write_all(mddev->bitmap);
+		mddev->bitmap_ops->write_all(mddev);
 
 	name = test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery) ?
 			"reshape" : "resync";
@@ -9485,7 +9530,7 @@ static void unregister_sync_thread(struct mddev *mddev)
 void md_check_recovery(struct mddev *mddev)
 {
 	if (mddev->bitmap)
-		md_bitmap_daemon_work(mddev);
+		mddev->bitmap_ops->daemon_work(mddev);
 
 	if (signal_pending(current)) {
 		if (mddev->pers->sync_request && !mddev->external) {
@@ -9856,7 +9901,7 @@ static void check_sb_changes(struct mddev *mddev, struct md_rdev *rdev)
 		if (ret)
 			pr_info("md-cluster: resize failed\n");
 		else
-			md_bitmap_update_sb(mddev->bitmap);
+			mddev->bitmap_ops->update_sb(mddev->bitmap);
 	}
 
 	/* Check for change of roles in the active devices */

drivers/md/md.h

@@ -535,7 +535,8 @@ struct mddev {
 	struct percpu_ref		writes_pending;
 	int				sync_checkers;	/* # of threads checking writes_pending */
 
-	struct bitmap			*bitmap; /* the bitmap for the device */
+	void				*bitmap; /* the bitmap for the device */
+	struct bitmap_operations	*bitmap_ops;
 	struct {
 		struct file		*file; /* the bitmap file */
 		loff_t			offset; /* offset from superblock of

drivers/md/raid1-10.c

@@ -140,7 +140,7 @@ static inline bool raid1_add_bio_to_plug(struct mddev *mddev, struct bio *bio,
 	 * If bitmap is not enabled, it's safe to submit the io directly, and
 	 * this can get optimal performance.
 	 */
-	if (!md_bitmap_enabled(mddev->bitmap)) {
+	if (!mddev->bitmap_ops->enabled(mddev)) {
 		raid1_submit_write(bio);
 		return true;
 	}
@@ -166,12 +166,9 @@ static inline bool raid1_add_bio_to_plug(struct mddev *mddev, struct bio *bio,
  * while current io submission must wait for bitmap io to be done. In order to
  * avoid such deadlock, submit bitmap io asynchronously.
  */
-static inline void raid1_prepare_flush_writes(struct bitmap *bitmap)
+static inline void raid1_prepare_flush_writes(struct mddev *mddev)
 {
-	if (current->bio_list)
-		md_bitmap_unplug_async(bitmap);
-	else
-		md_bitmap_unplug(bitmap);
+	mddev->bitmap_ops->unplug(mddev, current->bio_list == NULL);
 }
 
 /*

drivers/md/raid1.c

@@ -411,18 +411,20 @@ static void raid1_end_read_request(struct bio *bio)
 
 static void close_write(struct r1bio *r1_bio)
 {
+	struct mddev *mddev = r1_bio->mddev;
+
 	/* it really is the end of this request */
 	if (test_bit(R1BIO_BehindIO, &r1_bio->state)) {
 		bio_free_pages(r1_bio->behind_master_bio);
 		bio_put(r1_bio->behind_master_bio);
 		r1_bio->behind_master_bio = NULL;
 	}
+
 	/* clear the bitmap if all writes complete successfully */
-	md_bitmap_endwrite(r1_bio->mddev->bitmap, r1_bio->sector,
-			   r1_bio->sectors,
+	mddev->bitmap_ops->endwrite(mddev, r1_bio->sector, r1_bio->sectors,
 				    !test_bit(R1BIO_Degraded, &r1_bio->state),
 				    test_bit(R1BIO_BehindIO, &r1_bio->state));
-	md_write_end(r1_bio->mddev);
+	md_write_end(mddev);
 }
 
 static void r1_bio_write_done(struct r1bio *r1_bio)
@@ -894,7 +896,7 @@ static void wake_up_barrier(struct r1conf *conf)
 static void flush_bio_list(struct r1conf *conf, struct bio *bio)
 {
 	/* flush any pending bitmap writes to disk before proceeding w/ I/O */
-	raid1_prepare_flush_writes(conf->mddev->bitmap);
+	raid1_prepare_flush_writes(conf->mddev);
 	wake_up_barrier(conf);
 
 	while (bio) { /* submit pending writes */
@@ -1311,7 +1313,6 @@ static void raid1_read_request(struct mddev *mddev, struct bio *bio,
 	struct r1conf *conf = mddev->private;
 	struct raid1_info *mirror;
 	struct bio *read_bio;
-	struct bitmap *bitmap = mddev->bitmap;
 	const enum req_op op = bio_op(bio);
 	const blk_opf_t do_sync = bio->bi_opf & REQ_SYNC;
 	int max_sectors;
@@ -1364,15 +1365,13 @@ static void raid1_read_request(struct mddev *mddev, struct bio *bio,
 				    (unsigned long long)r1_bio->sector,
 				    mirror->rdev->bdev);
 
-	if (test_bit(WriteMostly, &mirror->rdev->flags) &&
-	    bitmap) {
+	if (test_bit(WriteMostly, &mirror->rdev->flags)) {
 		/*
 		 * Reading from a write-mostly device must take care not to
 		 * over-take any writes that are 'behind'
 		 */
 		mddev_add_trace_msg(mddev, "raid1 wait behind writes");
-		wait_event(bitmap->behind_wait,
-			   atomic_read(&bitmap->behind_writes) == 0);
+		mddev->bitmap_ops->wait_behind_writes(mddev);
 	}
 
 	if (max_sectors < bio_sectors(bio)) {
@@ -1413,7 +1412,6 @@ static void raid1_write_request(struct mddev *mddev, struct bio *bio,
 	struct r1conf *conf = mddev->private;
 	struct r1bio *r1_bio;
 	int i, disks;
-	struct bitmap *bitmap = mddev->bitmap;
 	unsigned long flags;
 	struct md_rdev *blocked_rdev;
 	int first_clone;
@@ -1566,7 +1564,7 @@ static void raid1_write_request(struct mddev *mddev, struct bio *bio,
 	 * at a time and thus needs a new bio that can fit the whole payload
 	 * this bio in page sized chunks.
 	 */
-	if (write_behind && bitmap)
+	if (write_behind && mddev->bitmap)
 		max_sectors = min_t(int, max_sectors,
 				    BIO_MAX_VECS * (PAGE_SIZE >> 9));
 	if (max_sectors < bio_sectors(bio)) {
@@ -1593,18 +1591,22 @@ static void raid1_write_request(struct mddev *mddev, struct bio *bio,
 			continue;
 
 		if (first_clone) {
+			unsigned long max_write_behind =
+				mddev->bitmap_info.max_write_behind;
+			struct md_bitmap_stats stats;
+			int err;
+
 			/* do behind I/O ?
 			 * Not if there are too many, or cannot
 			 * allocate memory, or a reader on WriteMostly
 			 * is waiting for behind writes to flush */
-			if (bitmap && write_behind &&
-			    (atomic_read(&bitmap->behind_writes)
-			     < mddev->bitmap_info.max_write_behind) &&
-			    !waitqueue_active(&bitmap->behind_wait)) {
+			err = mddev->bitmap_ops->get_stats(mddev->bitmap, &stats);
+			if (!err && write_behind && !stats.behind_wait &&
+			    stats.behind_writes < max_write_behind)
 				alloc_behind_master_bio(r1_bio, bio);
-			}
 
-			md_bitmap_startwrite(bitmap, r1_bio->sector, r1_bio->sectors,
+			mddev->bitmap_ops->startwrite(
+				mddev, r1_bio->sector, r1_bio->sectors,
 				test_bit(R1BIO_BehindIO, &r1_bio->state));
 			first_clone = 0;
 		}
@@ -2023,7 +2025,7 @@ static void abort_sync_write(struct mddev *mddev, struct r1bio *r1_bio)
 
 	/* make sure these bits don't get cleared. */
 	do {
-		md_bitmap_end_sync(mddev->bitmap, s, &sync_blocks, 1);
+		mddev->bitmap_ops->end_sync(mddev, s, &sync_blocks);
 		s += sync_blocks;
 		sectors_to_go -= sync_blocks;
 	} while (sectors_to_go > 0);
@@ -2752,7 +2754,7 @@ static sector_t raid1_sync_request(struct mddev *mddev, sector_t sector_nr,
 	int wonly = -1;
 	int write_targets = 0, read_targets = 0;
 	sector_t sync_blocks;
-	int still_degraded = 0;
+	bool still_degraded = false;
 	int good_sectors = RESYNC_SECTORS;
 	int min_bad = 0; /* number of sectors that are bad in all devices */
 	int idx = sector_to_idx(sector_nr);
@@ -2769,12 +2771,12 @@ static sector_t raid1_sync_request(struct mddev *mddev, sector_t sector_nr,
 		 * We can find the current addess in mddev->curr_resync
 		 */
 		if (mddev->curr_resync < max_sector) /* aborted */
-			md_bitmap_end_sync(mddev->bitmap, mddev->curr_resync,
-					   &sync_blocks, 1);
+			mddev->bitmap_ops->end_sync(mddev, mddev->curr_resync,
+						    &sync_blocks);
 		else /* completed sync */
 			conf->fullsync = 0;
 
-		md_bitmap_close_sync(mddev->bitmap);
+		mddev->bitmap_ops->close_sync(mddev);
 		close_sync(conf);
 
 		if (mddev_is_clustered(mddev)) {
@@ -2794,7 +2796,7 @@ static sector_t raid1_sync_request(struct mddev *mddev, sector_t sector_nr,
 	/* before building a request, check if we can skip these blocks..
 	 * This call the bitmap_start_sync doesn't actually record anything
 	 */
-	if (!md_bitmap_start_sync(mddev->bitmap, sector_nr, &sync_blocks, 1) &&
+	if (!mddev->bitmap_ops->start_sync(mddev, sector_nr, &sync_blocks, true) &&
 	    !conf->fullsync && !test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery)) {
 		/* We can skip this block, and probably several more */
 		*skipped = 1;
@@ -2812,9 +2814,9 @@ static sector_t raid1_sync_request(struct mddev *mddev, sector_t sector_nr,
 	 * sector_nr + two times RESYNC_SECTORS
 	 */
 
-	md_bitmap_cond_end_sync(mddev->bitmap, sector_nr,
-		mddev_is_clustered(mddev) && (sector_nr + 2 * RESYNC_SECTORS > conf->cluster_sync_high));
-
+	mddev->bitmap_ops->cond_end_sync(mddev, sector_nr,
+		mddev_is_clustered(mddev) &&
+		(sector_nr + 2 * RESYNC_SECTORS > conf->cluster_sync_high));
 
 	if (raise_barrier(conf, sector_nr))
 		return 0;
@@ -2845,7 +2847,7 @@ static sector_t raid1_sync_request(struct mddev *mddev, sector_t sector_nr,
 		if (rdev == NULL ||
 		    test_bit(Faulty, &rdev->flags)) {
 			if (i < conf->raid_disks)
-				still_degraded = 1;
+				still_degraded = true;
 		} else if (!test_bit(In_sync, &rdev->flags)) {
 			bio->bi_opf = REQ_OP_WRITE;
 			bio->bi_end_io = end_sync_write;
@@ -2969,7 +2971,7 @@ static sector_t raid1_sync_request(struct mddev *mddev, sector_t sector_nr,
 		if (len == 0)
 			break;
 		if (sync_blocks == 0) {
-			if (!md_bitmap_start_sync(mddev->bitmap, sector_nr,
+			if (!mddev->bitmap_ops->start_sync(mddev, sector_nr,
 						&sync_blocks, still_degraded) &&
 			    !conf->fullsync &&
 			    !test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery))
@@ -3294,14 +3296,16 @@ static int raid1_resize(struct mddev *mddev, sector_t sectors)
 	 * worth it.
 	 */
 	sector_t newsize = raid1_size(mddev, sectors, 0);
+	int ret;
+
 	if (mddev->external_size &&
 	    mddev->array_sectors > newsize)
 		return -EINVAL;
-	if (mddev->bitmap) {
-		int ret = md_bitmap_resize(mddev->bitmap, newsize, 0, 0);
+
+	ret = mddev->bitmap_ops->resize(mddev, newsize, 0, false);
 	if (ret)
 		return ret;
-	}
+
 	md_set_array_sectors(mddev, newsize);
 	if (sectors > mddev->dev_sectors &&
 	    mddev->recovery_cp > mddev->dev_sectors) {

drivers/md/raid10.c

@@ -426,12 +426,13 @@ static void raid10_end_read_request(struct bio *bio)
 
 static void close_write(struct r10bio *r10_bio)
 {
+	struct mddev *mddev = r10_bio->mddev;
+
 	/* clear the bitmap if all writes complete successfully */
-	md_bitmap_endwrite(r10_bio->mddev->bitmap, r10_bio->sector,
-			   r10_bio->sectors,
+	mddev->bitmap_ops->endwrite(mddev, r10_bio->sector, r10_bio->sectors,
 				    !test_bit(R10BIO_Degraded, &r10_bio->state),
-			   0);
-	md_write_end(r10_bio->mddev);
+				    false);
+	md_write_end(mddev);
 }
 
 static void one_write_done(struct r10bio *r10_bio)
@@ -884,7 +885,7 @@ static void flush_pending_writes(struct r10conf *conf)
 		__set_current_state(TASK_RUNNING);
 
 		blk_start_plug(&plug);
-		raid1_prepare_flush_writes(conf->mddev->bitmap);
+		raid1_prepare_flush_writes(conf->mddev);
 		wake_up(&conf->wait_barrier);
 
 		while (bio) { /* submit pending writes */
@@ -1100,7 +1101,7 @@ static void raid10_unplug(struct blk_plug_cb *cb, bool from_schedule)
 
 	/* we aren't scheduling, so we can do the write-out directly. */
 	bio = bio_list_get(&plug->pending);
-	raid1_prepare_flush_writes(mddev->bitmap);
+	raid1_prepare_flush_writes(mddev);
 	wake_up_barrier(conf);
 
 	while (bio) { /* submit pending writes */
@@ -1492,7 +1493,8 @@ static void raid10_write_request(struct mddev *mddev, struct bio *bio,
 	md_account_bio(mddev, &bio);
 	r10_bio->master_bio = bio;
 	atomic_set(&r10_bio->remaining, 1);
-	md_bitmap_startwrite(mddev->bitmap, r10_bio->sector, r10_bio->sectors, 0);
+	mddev->bitmap_ops->startwrite(mddev, r10_bio->sector, r10_bio->sectors,
+				      false);
 
 	for (i = 0; i < conf->copies; i++) {
 		if (r10_bio->devs[i].bio)
@@ -3192,13 +3194,15 @@ static sector_t raid10_sync_request(struct mddev *mddev, sector_t sector_nr,
 
 		if (mddev->curr_resync < max_sector) { /* aborted */
 			if (test_bit(MD_RECOVERY_SYNC, &mddev->recovery))
-				md_bitmap_end_sync(mddev->bitmap, mddev->curr_resync,
-						   &sync_blocks, 1);
+				mddev->bitmap_ops->end_sync(mddev,
+							    mddev->curr_resync,
+							    &sync_blocks);
 			else for (i = 0; i < conf->geo.raid_disks; i++) {
 				sector_t sect =
 					raid10_find_virt(conf, mddev->curr_resync, i);
-				md_bitmap_end_sync(mddev->bitmap, sect,
-						   &sync_blocks, 1);
+
+				mddev->bitmap_ops->end_sync(mddev, sect,
+							    &sync_blocks);
 			}
 		} else {
 			/* completed sync */
@@ -3218,7 +3222,7 @@ static sector_t raid10_sync_request(struct mddev *mddev, sector_t sector_nr,
 			}
 			conf->fullsync = 0;
 		}
-		md_bitmap_close_sync(mddev->bitmap);
+		mddev->bitmap_ops->close_sync(mddev);
 		close_sync(conf);
 		*skipped = 1;
 		return sectors_skipped;
@@ -3287,10 +3291,10 @@ static sector_t raid10_sync_request(struct mddev *mddev, sector_t sector_nr,
 		r10_bio = NULL;
 
 		for (i = 0 ; i < conf->geo.raid_disks; i++) {
-			int still_degraded;
+			bool still_degraded;
 			struct r10bio *rb2;
 			sector_t sect;
-			int must_sync;
+			bool must_sync;
 			int any_working;
 			struct raid10_info *mirror = &conf->mirrors[i];
 			struct md_rdev *mrdev, *mreplace;
@@ -3307,7 +3311,7 @@ static sector_t raid10_sync_request(struct mddev *mddev, sector_t sector_nr,
 			if (!mrdev && !mreplace)
 				continue;
 
-			still_degraded = 0;
+			still_degraded = false;
 			/* want to reconstruct this device */
 			rb2 = r10_bio;
 			sect = raid10_find_virt(conf, sector_nr, i);
@@ -3320,8 +3324,9 @@ static sector_t raid10_sync_request(struct mddev *mddev, sector_t sector_nr,
 			 * we only need to recover the block if it is set in
 			 * the bitmap
 			 */
-			must_sync = md_bitmap_start_sync(mddev->bitmap, sect,
-							 &sync_blocks, 1);
+			must_sync = mddev->bitmap_ops->start_sync(mddev, sect,
+								  &sync_blocks,
+								  true);
 			if (sync_blocks < max_sync)
 				max_sync = sync_blocks;
 			if (!must_sync &&
@@ -3359,12 +3364,12 @@ static sector_t raid10_sync_request(struct mddev *mddev, sector_t sector_nr,
 				struct md_rdev *rdev = conf->mirrors[j].rdev;
 
 				if (rdev == NULL || test_bit(Faulty, &rdev->flags)) {
-					still_degraded = 1;
+					still_degraded = false;
 					break;
 				}
 			}
 
-			must_sync = md_bitmap_start_sync(mddev->bitmap, sect,
+			must_sync = mddev->bitmap_ops->start_sync(mddev, sect,
 						&sync_blocks, still_degraded);
 
 			any_working = 0;
@@ -3538,12 +3543,13 @@ static sector_t raid10_sync_request(struct mddev *mddev, sector_t sector_nr,
 		 * safety reason, which ensures curr_resync_completed is
 		 * updated in bitmap_cond_end_sync.
 		 */
-		md_bitmap_cond_end_sync(mddev->bitmap, sector_nr,
+		mddev->bitmap_ops->cond_end_sync(mddev, sector_nr,
 					mddev_is_clustered(mddev) &&
 					(sector_nr + 2 * RESYNC_SECTORS > conf->cluster_sync_high));
 
-		if (!md_bitmap_start_sync(mddev->bitmap, sector_nr,
-					  &sync_blocks, mddev->degraded) &&
+		if (!mddev->bitmap_ops->start_sync(mddev, sector_nr,
+						   &sync_blocks,
+						   mddev->degraded) &&
 		    !conf->fullsync && !test_bit(MD_RECOVERY_REQUESTED,
 						 &mddev->recovery)) {
 			/* We can skip this block */
@@ -4190,6 +4196,7 @@ static int raid10_resize(struct mddev *mddev, sector_t sectors)
 	 */
 	struct r10conf *conf = mddev->private;
 	sector_t oldsize, size;
+	int ret;
 
 	if (mddev->reshape_position != MaxSector)
 		return -EBUSY;
@@ -4202,11 +4209,11 @@ static int raid10_resize(struct mddev *mddev, sector_t sectors)
 	if (mddev->external_size &&
 	    mddev->array_sectors > size)
 		return -EINVAL;
-	if (mddev->bitmap) {
-		int ret = md_bitmap_resize(mddev->bitmap, size, 0, 0);
+
+	ret = mddev->bitmap_ops->resize(mddev, size, 0, false);
 	if (ret)
 		return ret;
-	}
+
 	md_set_array_sectors(mddev, size);
 	if (sectors > mddev->dev_sectors &&
 	    mddev->recovery_cp > oldsize) {
@@ -4472,7 +4479,7 @@ static int raid10_start_reshape(struct mddev *mddev)
 		newsize = raid10_size(mddev, 0, conf->geo.raid_disks);
 
 		if (!mddev_is_clustered(mddev)) {
-			ret = md_bitmap_resize(mddev->bitmap, newsize, 0, 0);
+			ret = mddev->bitmap_ops->resize(mddev, newsize, 0, false);
 			if (ret)
 				goto abort;
 			else
@@ -4487,20 +4494,20 @@ static int raid10_start_reshape(struct mddev *mddev)
 
 		/*
 		 * some node is already performing reshape, and no need to
-		 * call md_bitmap_resize again since it should be called when
+		 * call bitmap_ops->resize again since it should be called when
 		 * receiving BITMAP_RESIZE msg
 		 */
 		if ((sb && (le32_to_cpu(sb->feature_map) &
 			    MD_FEATURE_RESHAPE_ACTIVE)) || (oldsize == newsize))
 			goto out;
 
-		ret = md_bitmap_resize(mddev->bitmap, newsize, 0, 0);
+		ret = mddev->bitmap_ops->resize(mddev, newsize, 0, false);
 		if (ret)
 			goto abort;
 
 		ret = md_cluster_ops->resize_bitmaps(mddev, newsize, oldsize);
 		if (ret) {
-			md_bitmap_resize(mddev->bitmap, oldsize, 0, 0);
+			mddev->bitmap_ops->resize(mddev, oldsize, 0, false);
 			goto abort;
 		}
 	}

drivers/md/raid5-cache.c

@@ -313,10 +313,10 @@ void r5c_handle_cached_data_endio(struct r5conf *conf,
 		if (sh->dev[i].written) {
 			set_bit(R5_UPTODATE, &sh->dev[i].flags);
 			r5c_return_dev_pending_writes(conf, &sh->dev[i]);
-			md_bitmap_endwrite(conf->mddev->bitmap, sh->sector,
-					   RAID5_STRIPE_SECTORS(conf),
+			conf->mddev->bitmap_ops->endwrite(conf->mddev,
+					sh->sector, RAID5_STRIPE_SECTORS(conf),
 					!test_bit(STRIPE_DEGRADED, &sh->state),
-					   0);
+					false);
 		}
 	}
 }

drivers/md/raid5.c

@@ -3563,8 +3563,8 @@ static void __add_stripe_bio(struct stripe_head *sh, struct bio *bi,
 		 */
 		set_bit(STRIPE_BITMAP_PENDING, &sh->state);
 		spin_unlock_irq(&sh->stripe_lock);
-		md_bitmap_startwrite(conf->mddev->bitmap, sh->sector,
-				     RAID5_STRIPE_SECTORS(conf), 0);
+		conf->mddev->bitmap_ops->startwrite(conf->mddev, sh->sector,
+					RAID5_STRIPE_SECTORS(conf), false);
 		spin_lock_irq(&sh->stripe_lock);
 		clear_bit(STRIPE_BITMAP_PENDING, &sh->state);
 		if (!sh->batch_head) {
@@ -3663,8 +3663,9 @@ handle_failed_stripe(struct r5conf *conf, struct stripe_head *sh,
 			bi = nextbi;
 		}
 		if (bitmap_end)
-			md_bitmap_endwrite(conf->mddev->bitmap, sh->sector,
-					   RAID5_STRIPE_SECTORS(conf), 0, 0);
+			conf->mddev->bitmap_ops->endwrite(conf->mddev,
+					sh->sector, RAID5_STRIPE_SECTORS(conf),
+					false, false);
 		bitmap_end = 0;
 		/* and fail all 'written' */
 		bi = sh->dev[i].written;
@@ -3709,8 +3710,9 @@ handle_failed_stripe(struct r5conf *conf, struct stripe_head *sh,
 			}
 		}
 		if (bitmap_end)
-			md_bitmap_endwrite(conf->mddev->bitmap, sh->sector,
-					   RAID5_STRIPE_SECTORS(conf), 0, 0);
+			conf->mddev->bitmap_ops->endwrite(conf->mddev,
+					sh->sector, RAID5_STRIPE_SECTORS(conf),
+					false, false);
 		/* If we were in the middle of a write the parity block might
 		 * still be locked - so just clear all R5_LOCKED flags
 		 */
@@ -4059,10 +4061,10 @@ static void handle_stripe_clean_event(struct r5conf *conf,
 					bio_endio(wbi);
 					wbi = wbi2;
 				}
-				md_bitmap_endwrite(conf->mddev->bitmap, sh->sector,
-						   RAID5_STRIPE_SECTORS(conf),
+				conf->mddev->bitmap_ops->endwrite(conf->mddev,
+					sh->sector, RAID5_STRIPE_SECTORS(conf),
 					!test_bit(STRIPE_DEGRADED, &sh->state),
-						   0);
+					false);
 				if (head_sh->batch_head) {
 					sh = list_first_entry(&sh->batch_list,
 							      struct stripe_head,
@@ -5788,13 +5790,10 @@ static void make_discard_request(struct mddev *mddev, struct bio *bi)
 		}
 		spin_unlock_irq(&sh->stripe_lock);
 		if (conf->mddev->bitmap) {
-			for (d = 0;
-			     d < conf->raid_disks - conf->max_degraded;
+			for (d = 0; d < conf->raid_disks - conf->max_degraded;
 			     d++)
-				md_bitmap_startwrite(mddev->bitmap,
-						     sh->sector,
-						     RAID5_STRIPE_SECTORS(conf),
-						     0);
+				mddev->bitmap_ops->startwrite(mddev, sh->sector,
+					RAID5_STRIPE_SECTORS(conf), false);
 			sh->bm_seq = conf->seq_flush + 1;
 			set_bit(STRIPE_BIT_DELAY, &sh->state);
 		}
@@ -6486,7 +6485,7 @@ static inline sector_t raid5_sync_request(struct mddev *mddev, sector_t sector_n
 	struct r5conf *conf = mddev->private;
 	struct stripe_head *sh;
 	sector_t sync_blocks;
-	int still_degraded = 0;
+	bool still_degraded = false;
 	int i;
 
 	if (sector_nr >= max_sector) {
@@ -6498,11 +6497,11 @@ static inline sector_t raid5_sync_request(struct mddev *mddev, sector_t sector_n
 		}
 
 		if (mddev->curr_resync < max_sector) /* aborted */
-			md_bitmap_end_sync(mddev->bitmap, mddev->curr_resync,
-					   &sync_blocks, 1);
+			mddev->bitmap_ops->end_sync(mddev, mddev->curr_resync,
+						    &sync_blocks);
 		else /* completed sync */
 			conf->fullsync = 0;
-		md_bitmap_close_sync(mddev->bitmap);
+		mddev->bitmap_ops->close_sync(mddev);
 
 		return 0;
 	}
@@ -6531,7 +6530,8 @@ static inline sector_t raid5_sync_request(struct mddev *mddev, sector_t sector_n
 	}
 	if (!test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery) &&
 	    !conf->fullsync &&
-	    !md_bitmap_start_sync(mddev->bitmap, sector_nr, &sync_blocks, 1) &&
+	    !mddev->bitmap_ops->start_sync(mddev, sector_nr, &sync_blocks,
+					   true) &&
 	    sync_blocks >= RAID5_STRIPE_SECTORS(conf)) {
 		/* we can skip this block, and probably more */
 		do_div(sync_blocks, RAID5_STRIPE_SECTORS(conf));
@@ -6540,7 +6540,7 @@ static inline sector_t raid5_sync_request(struct mddev *mddev, sector_t sector_n
 		return sync_blocks * RAID5_STRIPE_SECTORS(conf);
 	}
 
-	md_bitmap_cond_end_sync(mddev->bitmap, sector_nr, false);
+	mddev->bitmap_ops->cond_end_sync(mddev, sector_nr, false);
 
 	sh = raid5_get_active_stripe(conf, NULL, sector_nr,
 				     R5_GAS_NOBLOCK);
@@ -6559,10 +6559,11 @@ static inline sector_t raid5_sync_request(struct mddev *mddev, sector_t sector_n
 		struct md_rdev *rdev = conf->disks[i].rdev;
 
 		if (rdev == NULL || test_bit(Faulty, &rdev->flags))
-			still_degraded = 1;
+			still_degraded = true;
 	}
 
-	md_bitmap_start_sync(mddev->bitmap, sector_nr, &sync_blocks, still_degraded);
+	mddev->bitmap_ops->start_sync(mddev, sector_nr, &sync_blocks,
+				      still_degraded);
 
 	set_bit(STRIPE_SYNC_REQUESTED, &sh->state);
 	set_bit(STRIPE_HANDLE, &sh->state);
@@ -6767,7 +6768,7 @@ static void raid5d(struct md_thread *thread)
 			/* Now is a good time to flush some bitmap updates */
 			conf->seq_flush++;
 			spin_unlock_irq(&conf->device_lock);
-			md_bitmap_unplug(mddev->bitmap);
+			mddev->bitmap_ops->unplug(mddev, true);
 			spin_lock_irq(&conf->device_lock);
 			conf->seq_write = conf->seq_flush;
 			activate_bit_delay(conf, conf->temp_inactive_list);
@@ -8312,6 +8313,7 @@ static int raid5_resize(struct mddev *mddev, sector_t sectors)
 	 */
 	sector_t newsize;
 	struct r5conf *conf = mddev->private;
+	int ret;
 
 	if (raid5_has_log(conf) || raid5_has_ppl(conf))
 		return -EINVAL;
@@ -8320,11 +8322,11 @@ static int raid5_resize(struct mddev *mddev, sector_t sectors)
 	if (mddev->external_size &&
 	    mddev->array_sectors > newsize)
 		return -EINVAL;
-	if (mddev->bitmap) {
-		int ret = md_bitmap_resize(mddev->bitmap, sectors, 0, 0);
+
+	ret = mddev->bitmap_ops->resize(mddev, sectors, 0, false);
 	if (ret)
 		return ret;
-	}
+
 	md_set_array_sectors(mddev, newsize);
 	if (sectors > mddev->dev_sectors &&
 	    mddev->recovery_cp > mddev->dev_sectors) {