1 files changed, 88 insertions, 0 deletions

diff --git a/kernel/include/linux/dm-kcopyd.h b/kernel/include/linux/dm-kcopyd.h
new file mode 100644
index 000000000..f486d636b
--- /dev/null
+++ b/kernel/include/linux/dm-kcopyd.h
@@ -0,0 +1,88 @@
+/*
+ * Copyright (C) 2001 - 2003 Sistina Software
+ * Copyright (C) 2004 - 2008 Red Hat, Inc. All rights reserved.
+ *
+ * kcopyd provides a simple interface for copying an area of one
+ * block-device to one or more other block-devices, either synchronous
+ * or with an asynchronous completion notification.
+ *
+ * This file is released under the GPL.
+ */
+
+#ifndef _LINUX_DM_KCOPYD_H
+#define _LINUX_DM_KCOPYD_H
+
+#ifdef __KERNEL__
+
+#include <linux/dm-io.h>
+
+/* FIXME: make this configurable */
+#define DM_KCOPYD_MAX_REGIONS 8
+
+#define DM_KCOPYD_IGNORE_ERROR 1
+
+struct dm_kcopyd_throttle {
+	unsigned throttle;
+	unsigned num_io_jobs;
+	unsigned io_period;
+	unsigned total_period;
+	unsigned last_jiffies;
+};
+
+/*
+ * kcopyd clients that want to support throttling must pass an initialised
+ * dm_kcopyd_throttle struct into dm_kcopyd_client_create().
+ * Two or more clients may share the same instance of this struct between
+ * them if they wish to be throttled as a group.
+ *
+ * This macro also creates a corresponding module parameter to configure
+ * the amount of throttling.
+ */
+#define DECLARE_DM_KCOPYD_THROTTLE_WITH_MODULE_PARM(name, description)	\
+static struct dm_kcopyd_throttle dm_kcopyd_throttle = { 100, 0, 0, 0, 0 }; \
+module_param_named(name, dm_kcopyd_throttle.throttle, uint, 0644); \
+MODULE_PARM_DESC(name, description)
+
+/*
+ * To use kcopyd you must first create a dm_kcopyd_client object.
+ * throttle can be NULL if you don't want any throttling.
+ */
+struct dm_kcopyd_client;
+struct dm_kcopyd_client *dm_kcopyd_client_create(struct dm_kcopyd_throttle *throttle);
+void dm_kcopyd_client_destroy(struct dm_kcopyd_client *kc);
+
+/*
+ * Submit a copy job to kcopyd.  This is built on top of the
+ * previous three fns.
+ *
+ * read_err is a boolean,
+ * write_err is a bitset, with 1 bit for each destination region
+ */
+typedef void (*dm_kcopyd_notify_fn)(int read_err, unsigned long write_err,
+				    void *context);
+
+int dm_kcopyd_copy(struct dm_kcopyd_client *kc, struct dm_io_region *from,
+		   unsigned num_dests, struct dm_io_region *dests,
+		   unsigned flags, dm_kcopyd_notify_fn fn, void *context);
+
+/*
+ * Prepare a callback and submit it via the kcopyd thread.
+ *
+ * dm_kcopyd_prepare_callback allocates a callback structure and returns it.
+ * It must not be called from interrupt context.
+ * The returned value should be passed into dm_kcopyd_do_callback.
+ *
+ * dm_kcopyd_do_callback submits the callback.
+ * It may be called from interrupt context.
+ * The callback is issued from the kcopyd thread.
+ */
+void *dm_kcopyd_prepare_callback(struct dm_kcopyd_client *kc,
+				 dm_kcopyd_notify_fn fn, void *context);
+void dm_kcopyd_do_callback(void *job, int read_err, unsigned long write_err);
+
+int dm_kcopyd_zero(struct dm_kcopyd_client *kc,
+		   unsigned num_dests, struct dm_io_region *dests,
+		   unsigned flags, dm_kcopyd_notify_fn fn, void *context);
+
+#endif	/* __KERNEL__ */
+#endif	/* _LINUX_DM_KCOPYD_H */