[PATCH RFC v2 14/14] md/md-llbitmap: add Kconfig

[Yu Kuai]

From: Yu Kuai <yukuai3@xxxxxxxxxx>

A new config MD_LLBITMAP is added, user can now using llbitmap to
replace the old bitmap.

Signed-off-by: Yu Kuai <yukuai3@xxxxxxxxxx>
---
 drivers/md/Kconfig       | 12 ++++++++++++
 drivers/md/Makefile      |  1 +
 drivers/md/md-bitmap.h   | 13 +++++++++++++
 drivers/md/md-llbitmap.c | 27 +++++++++++++++++++++++++++
 drivers/md/md.c          |  7 +++++++
 5 files changed, 60 insertions(+)

diff --git a/drivers/md/Kconfig b/drivers/md/Kconfig
index 0da07182494c..e5dc893ad09a 100644
--- a/drivers/md/Kconfig
+++ b/drivers/md/Kconfig
@@ -52,6 +52,18 @@ config MD_BITMAP
 
 	  If unsure, say Y.
 
+config MD_LLBITMAP
+	bool "MD RAID lockless bitmap support"
+	default n
+	depends on BLK_DEV_MD
+	help
+	  If you say Y here, support for the lockless write intent bitmap will
+	  be enabled.
+
+	  Note, this is an experimental feature.
+
+	  If unsure, say N.
+
 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 811731840a5c..e70e4d3cbe29 100644
--- a/drivers/md/Makefile
+++ b/drivers/md/Makefile
@@ -39,6 +39,7 @@ linear-y       += md-linear.o
 obj-$(CONFIG_MD_LINEAR)		+= linear.o
 obj-$(CONFIG_MD_RAID0)		+= raid0.o
 obj-$(CONFIG_MD_BITMAP)		+= md-bitmap.o
+obj-$(CONFIG_MD_LLBITMAP)	+= md-llbitmap.o
 obj-$(CONFIG_MD_RAID1)		+= raid1.o
 obj-$(CONFIG_MD_RAID10)		+= raid10.o
 obj-$(CONFIG_MD_RAID456)	+= raid456.o
diff --git a/drivers/md/md-bitmap.h b/drivers/md/md-bitmap.h
index 7a3cd2f70772..ee0c65e87dba 100644
--- a/drivers/md/md-bitmap.h
+++ b/drivers/md/md-bitmap.h
@@ -171,4 +171,17 @@ static inline void md_bitmap_exit(void)
 }
 #endif
 
+#ifdef CONFIG_MD_LLBITMAP
+int md_llbitmap_init(void);
+void md_llbitmap_exit(void);
+#else
+static inline int md_llbitmap_init(void)
+{
+	return 0;
+}
+static inline void md_llbitmap_exit(void)
+{
+}
+#endif
+
 #endif
diff --git a/drivers/md/md-llbitmap.c b/drivers/md/md-llbitmap.c
index 88ba29111e13..5e2f89137feb 100644
--- a/drivers/md/md-llbitmap.c
+++ b/drivers/md/md-llbitmap.c
@@ -1381,3 +1381,30 @@ static struct bitmap_operations llbitmap_ops = {
 
 	.group			= &md_llbitmap_group,
 };
+
+int md_llbitmap_init(void)
+{
+	md_llbitmap_io_wq = alloc_workqueue("md_llbitmap_io",
+					 WQ_MEM_RECLAIM | WQ_UNBOUND, 0);
+	if (!md_llbitmap_io_wq)
+		return -ENOMEM;
+
+	md_llbitmap_unplug_wq = alloc_workqueue("md_llbitmap_unplug",
+					 WQ_MEM_RECLAIM | WQ_UNBOUND, 0);
+	if (!md_llbitmap_unplug_wq) {
+		destroy_workqueue(md_llbitmap_io_wq);
+		md_llbitmap_io_wq = NULL;
+		return -ENOMEM;
+	}
+
+	return register_md_submodule(&llbitmap_ops.head);
+}
+
+void md_llbitmap_exit(void)
+{
+	destroy_workqueue(md_llbitmap_io_wq);
+	md_llbitmap_io_wq = NULL;
+	destroy_workqueue(md_llbitmap_unplug_wq);
+	md_llbitmap_unplug_wq = NULL;
+	unregister_md_submodule(&llbitmap_ops.head);
+}
diff --git a/drivers/md/md.c b/drivers/md/md.c
index c1f13288069a..4d05eae69795 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -10104,6 +10104,10 @@ static int __init md_init(void)
 	if (ret)
 		return ret;
 
+	ret = md_llbitmap_init();
+	if (ret)
+		goto err_bitmap;
+
 	ret = -ENOMEM;
 	md_wq = alloc_workqueue("md", WQ_MEM_RECLAIM, 0);
 	if (!md_wq)
@@ -10135,6 +10139,8 @@ static int __init md_init(void)
 err_misc_wq:
 	destroy_workqueue(md_wq);
 err_wq:
+	md_llbitmap_exit();
+err_bitmap:
 	md_bitmap_exit();
 	return ret;
 }
@@ -10439,6 +10445,7 @@ static __exit void md_exit(void)
 
 	destroy_workqueue(md_misc_wq);
 	destroy_workqueue(md_wq);
+	md_llbitmap_exit();
 	md_bitmap_exit();
 }
 
-- 
2.39.2