md/md-bitmap: introduce CONFIG_MD_BITMAP

Now that all implementations are internal, it's sensible to add a config
option for md-bitmap, and it's a good way for isolation.

Link: https://lore.kernel.org/linux-raid/20250707012711.376844-16-yukuai1@huaweicloud.com
Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Reviewed-by: Xiao Ni <xni@redhat.com>

diff --git a/drivers/md/Kconfig b/drivers/md/Kconfig
index ddb37f6670de887c8a9bae897df7220e661dd3ae..f913579e731cb240e347096771be45a73477edcd 100644 (file)
--- a/drivers/md/Kconfig
+++ b/drivers/md/Kconfig
@@ -37,6 +37,21 @@ config BLK_DEV_MD
 
          If unsure, say N.
 
+config MD_BITMAP
+       bool "MD 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 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
@@ -174,6 +190,7 @@ config MD_RAID456
 
 config MD_CLUSTER
        tristate "Cluster Support for MD"
+       select MD_BITMAP
        depends on BLK_DEV_MD
        depends on DLM
        default n
@@ -393,6 +410,7 @@ 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 87bdfc9fe14c559aed4f3ef408ba3d2b0a055973..2e18147a9c405f86a04db29fc7853324eca37d16 100644 (file)
--- a/drivers/md/Makefile
+++ b/drivers/md/Makefile
@@ -27,7 +27,8 @@ 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
+md-mod-$(CONFIG_MD_BITMAP)     += md-bitmap.o
 raid456-y      += raid5.o raid5-cache.o raid5-ppl.o
 linear-y       += md-linear.o
 

diff --git a/drivers/md/md-bitmap.c b/drivers/md/md-bitmap.c
index 29de99e0de3e11cce2ce9ec4b1a6a6e81caf2eda..5f62f2fd8f3f3bd51f4cff264c0971fee92db59d 100644 (file)
--- a/drivers/md/md-bitmap.c
+++ b/drivers/md/md-bitmap.c
@@ -224,6 +224,8 @@ 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);
 
@@ -2979,6 +2981,12 @@ static struct attribute_group md_bitmap_group = {
 };
 
 static struct bitmap_operations bitmap_ops = {
+       .head = {
+               .type   = MD_BITMAP,
+               .id     = ID_BITMAP,
+               .name   = "bitmap",
+       },
+
        .enabled                = bitmap_enabled,
        .create                 = bitmap_create,
        .resize                 = bitmap_resize,
@@ -3013,7 +3021,18 @@ static struct bitmap_operations bitmap_ops = {
        .group                  = &md_bitmap_group,
 };
 
-void mddev_set_bitmap_ops(struct mddev *mddev)
+int md_bitmap_init(void)
+{
+       md_bitmap_wq = alloc_workqueue("md_bitmap", WQ_MEM_RECLAIM | WQ_UNBOUND,
+                                      0);
+       if (!md_bitmap_wq)
+               return -ENOMEM;
+
+       return register_md_submodule(&bitmap_ops.head);
+}
+
+void md_bitmap_exit(void)
 {
-       mddev->bitmap_ops = &bitmap_ops;
+       destroy_workqueue(md_bitmap_wq);
+       unregister_md_submodule(&bitmap_ops.head);
 }

diff --git a/drivers/md/md-bitmap.h b/drivers/md/md-bitmap.h
index 61cfc650c69cf27d473cb5df2972168a621d079b..42f91755a341967845cb9e393adc564566e3c2ed 100644 (file)
--- a/drivers/md/md-bitmap.h
+++ b/drivers/md/md-bitmap.h
@@ -62,6 +62,8 @@ struct md_bitmap_stats {
 };
 
 struct bitmap_operations {
+       struct md_submodule_head head;
+
        bool (*enabled)(void *data, bool flush);
        int (*create)(struct mddev *mddev);
        int (*resize)(struct mddev *mddev, sector_t blocks, int chunksize);
@@ -105,8 +107,6 @@ struct bitmap_operations {
 };
 
 /* the bitmap API */
-void mddev_set_bitmap_ops(struct mddev *mddev);
-
 static inline bool md_bitmap_registered(struct mddev *mddev)
 {
        return mddev->bitmap_ops != NULL;
@@ -147,4 +147,17 @@ static inline void md_bitmap_end_sync(struct mddev *mddev, sector_t offset,
        mddev->bitmap_ops->end_sync(mddev, offset, blocks);
 }
 
+#ifdef CONFIG_MD_BITMAP
+int md_bitmap_init(void);
+void md_bitmap_exit(void);
+#else
+static inline int md_bitmap_init(void)
+{
+       return 0;
+}
+static inline void md_bitmap_exit(void)
+{
+}
+#endif
+
 #endif

diff --git a/drivers/md/md.c b/drivers/md/md.c
index e750ae4883e62c2f65584c9790519ff8846f9862..fbc107b52819aa226a7a87358ca8b75ea2bffe68 100644 (file)
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -94,7 +94,6 @@ 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);
@@ -677,15 +676,34 @@ static void active_io_release(struct percpu_ref *ref)
 
 static void no_op(struct percpu_ref *r) {}
 
+static void mddev_set_bitmap_ops(struct mddev *mddev, enum md_submodule_id id)
+{
+       xa_lock(&md_submodule);
+       mddev->bitmap_ops = xa_load(&md_submodule, id);
+       xa_unlock(&md_submodule);
+       if (!mddev->bitmap_ops)
+               pr_warn_once("md: can't find bitmap id %d\n", id);
+}
+
+static void mddev_clear_bitmap_ops(struct mddev *mddev)
+{
+       mddev->bitmap_ops = NULL;
+}
+
 int mddev_init(struct mddev *mddev)
 {
+       /* TODO: support more versions */
+       mddev_set_bitmap_ops(mddev, ID_BITMAP);
 
        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;
        }
@@ -713,7 +731,6 @@ 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);
@@ -724,6 +741,7 @@ 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);
 }
@@ -10121,8 +10139,12 @@ static void md_geninit(void)
 
 static int __init md_init(void)
 {
-       int ret = -ENOMEM;
+       int ret = md_bitmap_init();
 
+       if (ret)
+               return ret;
+
+       ret = -ENOMEM;
        md_wq = alloc_workqueue("md", WQ_MEM_RECLAIM, 0);
        if (!md_wq)
                goto err_wq;
@@ -10131,11 +10153,6 @@ 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;
@@ -10154,12 +10171,11 @@ 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);
 err_wq:
+       md_bitmap_exit();
        return ret;
 }
 
@@ -10465,8 +10481,8 @@ 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);
+       md_bitmap_exit();
 }
 
 subsys_initcall(md_init);

diff --git a/drivers/md/md.h b/drivers/md/md.h
index 06364e15e8d16a9a956732b61d30a037ad058de7..081152c8de1fd638bf8e35ff69fcf8ccbdc360e1 100644 (file)
--- a/drivers/md/md.h
+++ b/drivers/md/md.h
@@ -38,7 +38,7 @@ enum md_submodule_id {
        ID_RAID6        = 6,
        ID_RAID10       = 10,
        ID_CLUSTER,
-       ID_BITMAP,      /* TODO */
+       ID_BITMAP,
        ID_LLBITMAP,    /* TODO */
 };
 
@@ -1012,7 +1012,6 @@ 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);