new file mode 100644
index 0000000000000..e98b4b241020a
--- /dev/null
+++ b/include/linux/multipath.h
@@ -0,0 +1,28 @@
Please add an SPDX tag.
OK, will add
And possibly a copyright.
I think that just the c file is fine.
+
+#ifndef _LIBMULTIPATH_H
+#define _LIBMULTIPATH_H
+
+#include <linux/blkdev.h>
+#include <linux/srcu.h>
+
+struct mpath_device {
+ struct list_head siblings;
+ struct gendisk *disk;
+};
+
+struct mpath_head {
+ struct srcu_struct srcu;
+ struct list_head dev_list; /* list of all mpath_devs */
+ struct mutex lock;
+
+ refcount_t refcount;
+
+ struct mpath_device __rcu *current_path[MAX_NUMNODES];
+};
+
+int mpath_get_head(struct mpath_head *mpath_head);
+void mpath_put_head(struct mpath_head *mpath_head);
+int mpath_head_init(struct mpath_head *mpath_head);
+void mpath_head_uninit(struct mpath_head *mpath_head);
+
+#endif // _LIBMULTIPATH_H
diff --git a/lib/Kconfig b/lib/Kconfig
index 55748b68714e0..d0258bef374a1 100644
--- a/lib/Kconfig
+++ b/lib/Kconfig
@@ -636,3 +636,9 @@ config UNION_FIND
config MIN_HEAP
bool
+
+config LIBMULTIPATH
+ bool "MULTIPATH BLOCK DRIVER LIBRARY"
+ depends on BLOCK
+ help
+ If you say yes here then you get a multipath lib for block drivers
diff --git a/lib/Makefile b/lib/Makefile
index 7f75cc6edf94a..7ba5e13be4171 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -334,3 +334,5 @@ CONTEXT_ANALYSIS_test_context-analysis.o := y
obj-$(CONFIG_CONTEXT_ANALYSIS_TEST) += test_context-analysis.o
subdir-$(CONFIG_FORTIFY_SOURCE) += test_fortify
+
+obj-$(CONFIG_LIBMULTIPATH) += multipath.o
diff --git a/lib/multipath.c b/lib/multipath.c
new file mode 100644
index 0000000000000..9cc398d266adf
--- /dev/null
+++ b/lib/multipath.c
@@ -0,0 +1,66 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (c) 2017-2018 Christoph Hellwig.
A bit unusual, creating a new file and add a copyright
from _another_ person ...
This code is really just a refactoring of the NVMe multipath code. Since
Christoph copyrighted that, I think it only proper to add his copyright
here.
I'll remove it if Christoph wants.
Otherwise:
Reviewed-by: Hannes Reinecke <[email protected]>
Thanks
