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Message-Id: <20241024131325.2250880-5-yukuai1@huaweicloud.com>
Date: Thu, 24 Oct 2024 21:13:25 +0800
From: Yu Kuai <yukuai1@...weicloud.com>
To: song@...nel.org
Cc: linux-raid@...r.kernel.org,
linux-kernel@...r.kernel.org,
yukuai3@...wei.com,
yukuai1@...weicloud.com,
yi.zhang@...wei.com,
yangerkun@...wei.com
Subject: [PATCH RFC 4/4] md/md-bitmap: support to build md-bitmap as kernel module
From: Yu Kuai <yukuai3@...wei.com>
Now that all implementations are internal, it's sensible to build it as
kernel module now.
Signed-off-by: Yu Kuai <yukuai3@...wei.com>
---
drivers/md/Kconfig | 15 +++++++
drivers/md/Makefile | 4 +-
drivers/md/md-bitmap.c | 28 +++++++++++-
drivers/md/md-bitmap.h | 8 +++-
drivers/md/md.c | 97 +++++++++++++++++++++++++++++++++++++-----
drivers/md/md.h | 1 -
6 files changed, 135 insertions(+), 18 deletions(-)
diff --git a/drivers/md/Kconfig b/drivers/md/Kconfig
index 1e9db8e4acdf..452d7292b617 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 "RAID bitmap support"
+ default y
+ depends on BLK_DEV_MD
+ help
+ If you say Y here, support for the write intent bitmap will be
+ enabled. The bitmap will be used to record the data regions that need
+ to be resynced after a power failure, preventing a full disk resync.
+ The bitmap size ranges from 4K to 132K, depending on the array size.
+ Each bit corresponds to 2 bytes of data and is managed in
+ self-maintained memory. All bits are protected by a disk-level
+ spinlock.
+
+ If unsure, say Y.
+
config MD_AUTODETECT
bool "Autodetect RAID arrays during kernel boot"
depends on BLK_DEV_MD=y
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 f68eb79e739d..148a479d32c0 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);
@@ -2970,6 +2972,9 @@ 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,
@@ -3001,7 +3006,26 @@ 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 0c19983453c7..9d1bf3c43125 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)(struct mddev *mddev);
int (*create)(struct mddev *mddev, int slot);
int (*resize)(struct mddev *mddev, sector_t blocks, int chunksize);
@@ -110,7 +114,7 @@ struct bitmap_operations {
struct attribute_group *group;
};
-/* 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);
#endif
diff --git a/drivers/md/md.c b/drivers/md/md.c
index d16a3d0f2b90..09fac65b83b8 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);
@@ -630,15 +632,96 @@ 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;
+}
+
+/* TODO: support more versions */
+static int mddev_set_bitmap_ops(struct mddev *mddev)
+{
+ struct bitmap_operations *op = find_bitmap(1);
+
+ if (!op)
+ return -ENODEV;
+
+ mddev->bitmap_ops = op;
+ return 0;
+}
+
+static void mddev_clear_bitmap_ops(struct mddev *mddev)
+{
+ module_put(mddev->bitmap_ops->owner);
+ mddev->bitmap_ops = NULL;
+}
+
int mddev_init(struct mddev *mddev)
{
+ int ret = mddev_set_bitmap_ops(mddev);
+
+ if (ret)
+ return ret;
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;
}
@@ -666,7 +749,6 @@ 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);
@@ -677,6 +759,7 @@ 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);
}
@@ -9898,11 +9981,6 @@ 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;
@@ -9921,8 +9999,6 @@ 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);
@@ -10229,7 +10305,6 @@ 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 5eaac1d84523..28347fb3af18 100644
--- a/drivers/md/md.h
+++ b/drivers/md/md.h
@@ -972,7 +972,6 @@ 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);
--
2.39.2
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