diff mbox series

[md-6.14,13/13] md/md-bitmap: support to build md-bitmap as kernel module

Message ID 20241225111546.1833250-14-yukuai1@huaweicloud.com (mailing list archive)
State New
Headers show
Series md/md-bitmap: support to build md-bitmap as kernel module | expand

Commit Message

Yu Kuai Dec. 25, 2024, 11:15 a.m. UTC
From: Yu Kuai <yukuai3@huawei.com>

Now that all implementations are internal, it's sensible to build it as
kernel module now.

Signed-off-by: Yu Kuai <yukuai3@huawei.com>
---
 drivers/md/Kconfig     | 18 ++++++++
 drivers/md/Makefile    |  4 +-
 drivers/md/md-bitmap.c | 28 +++++++++++-
 drivers/md/md-bitmap.h |  7 ++-
 drivers/md/md.c        | 96 +++++++++++++++++++++++++++++++++++++-----
 drivers/md/md.h        |  1 -
 6 files changed, 137 insertions(+), 17 deletions(-)
diff mbox series

Patch

diff --git a/drivers/md/Kconfig b/drivers/md/Kconfig
index 1e9db8e4acdf..be22ece66919 100644
--- a/drivers/md/Kconfig
+++ b/drivers/md/Kconfig
@@ -37,6 +37,21 @@  config BLK_DEV_MD
 
 	  If unsure, say N.
 
+config MD_BITMAP
+	tristate "MD RAID bitmap support"
+	default y
+	depends on BLK_DEV_MD
+	help
+	  If you say Y or M here, support for the write intent bitmap will be
+	  enabled. The bitmap can be used to optimize resync speed after power
+	  failure or readding a disk, limiting it to recorded dirty sectors in
+	  bitmap.
+
+	  This feature can be added to existing MD array or MD array can be
+	  created with bitmap via mdadm(8).
+
+	  If unsure, say Y.
+
 config MD_AUTODETECT
 	bool "Autodetect RAID arrays during kernel boot"
 	depends on BLK_DEV_MD=y
@@ -54,6 +69,7 @@  config MD_AUTODETECT
 config MD_BITMAP_FILE
 	bool "MD bitmap file support (deprecated)"
 	default y
+	depends on MD_BITMAP
 	help
 	  If you say Y here, support for write intent bitmaps in files on an
 	  external file system is enabled.  This is an alternative to the internal
@@ -161,6 +177,7 @@  config MD_RAID456
 
 config MD_CLUSTER
 	tristate "Cluster Support for MD"
+	select MD_BITMAP
 	depends on BLK_DEV_MD
 	depends on DLM
 	default n
@@ -379,6 +396,7 @@  config DM_RAID
        select MD_RAID1
        select MD_RAID10
        select MD_RAID456
+       select MD_BITMAP
        select BLK_DEV_MD
 	help
 	 A dm target that supports RAID1, RAID10, RAID4, RAID5 and RAID6 mappings
diff --git a/drivers/md/Makefile b/drivers/md/Makefile
index 476a214e4bdc..387670f766b7 100644
--- a/drivers/md/Makefile
+++ b/drivers/md/Makefile
@@ -27,14 +27,14 @@  dm-clone-y	+= dm-clone-target.o dm-clone-metadata.o
 dm-verity-y	+= dm-verity-target.o
 dm-zoned-y	+= dm-zoned-target.o dm-zoned-metadata.o dm-zoned-reclaim.o
 
-md-mod-y	+= md.o md-bitmap.o
+md-mod-y	+= md.o
 raid456-y	+= raid5.o raid5-cache.o raid5-ppl.o
 
 # Note: link order is important.  All raid personalities
 # and must come before md.o, as they each initialise
 # themselves, and md.o may use the personalities when it
 # auto-initialised.
-
+obj-$(CONFIG_MD_BITMAP)		+= md-bitmap.o
 obj-$(CONFIG_MD_RAID0)		+= raid0.o
 obj-$(CONFIG_MD_RAID1)		+= raid1.o
 obj-$(CONFIG_MD_RAID10)		+= raid10.o
diff --git a/drivers/md/md-bitmap.c b/drivers/md/md-bitmap.c
index 72cbbe0d3408..097339315517 100644
--- a/drivers/md/md-bitmap.c
+++ b/drivers/md/md-bitmap.c
@@ -212,6 +212,8 @@  struct bitmap {
 	int cluster_slot;
 };
 
+static struct workqueue_struct *md_bitmap_wq;
+
 static int __bitmap_resize(struct bitmap *bitmap, sector_t blocks,
 			   int chunksize, bool init);
 
@@ -2960,6 +2962,9 @@  static struct attribute_group md_bitmap_group = {
 };
 
 static struct bitmap_operations bitmap_ops = {
+	.version		= 1,
+	.owner			= THIS_MODULE,
+
 	.enabled		= bitmap_enabled,
 	.create			= bitmap_create,
 	.resize			= bitmap_resize,
@@ -2994,7 +2999,26 @@  static struct bitmap_operations bitmap_ops = {
 	.group			= &md_bitmap_group,
 };
 
-void mddev_set_bitmap_ops(struct mddev *mddev)
+static int __init bitmap_init(void)
+{
+	md_bitmap_wq = alloc_workqueue("md_bitmap", WQ_MEM_RECLAIM | WQ_UNBOUND,
+				       0);
+	if (!md_bitmap_wq)
+		return -ENOMEM;
+
+	INIT_LIST_HEAD(&bitmap_ops.list);
+	register_md_bitmap(&bitmap_ops);
+	return 0;
+}
+
+static void __exit bitmap_exit(void)
 {
-	mddev->bitmap_ops = &bitmap_ops;
+	destroy_workqueue(md_bitmap_wq);
+	unregister_md_bitmap(&bitmap_ops);
 }
+
+module_init(bitmap_init);
+module_exit(bitmap_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("Bitmap for MD");
diff --git a/drivers/md/md-bitmap.h b/drivers/md/md-bitmap.h
index fefa00bc438e..afd28d06aae9 100644
--- a/drivers/md/md-bitmap.h
+++ b/drivers/md/md-bitmap.h
@@ -71,6 +71,10 @@  struct md_bitmap_stats {
 };
 
 struct bitmap_operations {
+	int version;
+	struct module *owner;
+	struct list_head list;
+
 	bool (*enabled)(void *data);
 	int (*create)(struct mddev *mddev, int slot);
 	int (*resize)(struct mddev *mddev, sector_t blocks, int chunksize);
@@ -114,7 +118,8 @@  struct bitmap_operations {
 };
 
 /* the bitmap API */
-void mddev_set_bitmap_ops(struct mddev *mddev);
+void register_md_bitmap(struct bitmap_operations *op);
+void unregister_md_bitmap(struct bitmap_operations *op);
 
 static inline bool md_bitmap_registered(struct mddev *mddev)
 {
diff --git a/drivers/md/md.c b/drivers/md/md.c
index f1f70803439d..b1c9c0d4d5e7 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -83,6 +83,9 @@  static const char *action_name[NR_SYNC_ACTIONS] = {
 static LIST_HEAD(pers_list);
 static DEFINE_SPINLOCK(pers_lock);
 
+static LIST_HEAD(bitmap_list);
+static DEFINE_SPINLOCK(bitmap_lock);
+
 static const struct kobj_type md_ktype;
 
 const struct md_cluster_operations *md_cluster_ops;
@@ -100,7 +103,6 @@  static struct workqueue_struct *md_wq;
  * workqueue whith reconfig_mutex grabbed.
  */
 static struct workqueue_struct *md_misc_wq;
-struct workqueue_struct *md_bitmap_wq;
 
 static int remove_and_add_spares(struct mddev *mddev,
 				 struct md_rdev *this);
@@ -652,15 +654,95 @@  static void active_io_release(struct percpu_ref *ref)
 
 static void no_op(struct percpu_ref *r) {}
 
+void register_md_bitmap(struct bitmap_operations *op)
+{
+	pr_info("md: bitmap version %d registered\n", op->version);
+
+	spin_lock(&bitmap_lock);
+	list_add_tail(&op->list, &bitmap_list);
+	spin_unlock(&bitmap_lock);
+}
+EXPORT_SYMBOL_GPL(register_md_bitmap);
+
+void unregister_md_bitmap(struct bitmap_operations *op)
+{
+	pr_info("md: bitmap version %d unregistered\n", op->version);
+
+	spin_lock(&bitmap_lock);
+	list_del_init(&op->list);
+	spin_unlock(&bitmap_lock);
+}
+EXPORT_SYMBOL_GPL(unregister_md_bitmap);
+
+static struct bitmap_operations *__find_bitmap(int version)
+{
+	struct bitmap_operations *op;
+
+	list_for_each_entry(op, &bitmap_list, list)
+		if (op->version == version) {
+			if (try_module_get(op->owner))
+				return op;
+			else
+				return NULL;
+		}
+
+	return NULL;
+}
+
+static struct bitmap_operations *find_bitmap(int version)
+{
+	struct bitmap_operations *op = NULL;
+
+	spin_lock(&bitmap_lock);
+	op = __find_bitmap(version);
+	spin_unlock(&bitmap_lock);
+
+	if (op)
+		return op;
+
+	if (request_module("md-bitmap") != 0)
+		return NULL;
+
+	spin_lock(&bitmap_lock);
+	op = __find_bitmap(version);
+	spin_unlock(&bitmap_lock);
+
+	return op;
+}
+
+static void mddev_set_bitmap_ops(struct mddev *mddev, int version)
+{
+	struct bitmap_operations *op = find_bitmap(version);
+
+	if (!op)
+		pr_warn_once("md: can't find version %d bitmap\n", version);
+
+	mddev->bitmap_ops = op;
+}
+
+static void mddev_clear_bitmap_ops(struct mddev *mddev)
+{
+	if (!mddev->bitmap_ops)
+		return;
+
+	module_put(mddev->bitmap_ops->owner);
+	mddev->bitmap_ops = NULL;
+}
+
 int mddev_init(struct mddev *mddev)
 {
+	/* TODO: support more versions */
+	mddev_set_bitmap_ops(mddev, 1);
 
 	if (percpu_ref_init(&mddev->active_io, active_io_release,
-			    PERCPU_REF_ALLOW_REINIT, GFP_KERNEL))
+			    PERCPU_REF_ALLOW_REINIT, GFP_KERNEL)) {
+		mddev_clear_bitmap_ops(mddev);
 		return -ENOMEM;
+	}
 
 	if (percpu_ref_init(&mddev->writes_pending, no_op,
 			    PERCPU_REF_ALLOW_REINIT, GFP_KERNEL)) {
+		mddev_clear_bitmap_ops(mddev);
 		percpu_ref_exit(&mddev->active_io);
 		return -ENOMEM;
 	}
@@ -688,7 +770,6 @@  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);
@@ -699,6 +780,7 @@  EXPORT_SYMBOL_GPL(mddev_init);
 
 void mddev_destroy(struct mddev *mddev)
 {
+	mddev_clear_bitmap_ops(mddev);
 	percpu_ref_exit(&mddev->active_io);
 	percpu_ref_exit(&mddev->writes_pending);
 }
@@ -9977,11 +10059,6 @@  static int __init md_init(void)
 	if (!md_misc_wq)
 		goto err_misc_wq;
 
-	md_bitmap_wq = alloc_workqueue("md_bitmap", WQ_MEM_RECLAIM | WQ_UNBOUND,
-				       0);
-	if (!md_bitmap_wq)
-		goto err_bitmap_wq;
-
 	ret = __register_blkdev(MD_MAJOR, "md", md_probe);
 	if (ret < 0)
 		goto err_md;
@@ -10000,8 +10077,6 @@  static int __init md_init(void)
 err_mdp:
 	unregister_blkdev(MD_MAJOR, "md");
 err_md:
-	destroy_workqueue(md_bitmap_wq);
-err_bitmap_wq:
 	destroy_workqueue(md_misc_wq);
 err_misc_wq:
 	destroy_workqueue(md_wq);
@@ -10308,7 +10383,6 @@  static __exit void md_exit(void)
 	spin_unlock(&all_mddevs_lock);
 
 	destroy_workqueue(md_misc_wq);
-	destroy_workqueue(md_bitmap_wq);
 	destroy_workqueue(md_wq);
 }
 
diff --git a/drivers/md/md.h b/drivers/md/md.h
index 7e8276d2dadc..aea9693ff6ef 100644
--- a/drivers/md/md.h
+++ b/drivers/md/md.h
@@ -977,7 +977,6 @@  struct mdu_array_info_s;
 struct mdu_disk_info_s;
 
 extern int mdp_major;
-extern struct workqueue_struct *md_bitmap_wq;
 void md_autostart_arrays(int part);
 int md_set_array_info(struct mddev *mddev, struct mdu_array_info_s *info);
 int md_add_new_disk(struct mddev *mddev, struct mdu_disk_info_s *info);