dm bufio: move dm-bufio.h to include/linux/

Move dm-bufio.h to include/linux/ so that external GPL'd DM target
modules can use it.

It is better to allow the use of dm-bufio than force external modules
to implement the equivalent buffered IO mechanism in some new way. The
hope is this will encourage the use of dm-bufio; which will then make it
easier for a GPL'd external DM target module to be included upstream.

A couple dm-bufio EXPORT_SYMBOL exports have also been updated to use
EXPORT_SYMBOL_GPL.

Signed-off-by: Mikulas Patocka <[e-mail]>
Signed-off-by: Mike Snitzer <[e-mail]>

drivers/md/dm-bufio.c

···
  * This file is released under the GPL.
  */
 
-#include "dm-bufio.h"
+#include <linux/dm-bufio.h>
 
 #include <linux/device-mapper.h>
 #include <linux/dm-io.h>
···
 
 	dm_bufio_unlock(c);
 }
-EXPORT_SYMBOL(dm_bufio_forget);
+EXPORT_SYMBOL_GPL(dm_bufio_forget);
 
 void dm_bufio_set_minimum_buffers(struct dm_bufio_client *c, unsigned n)
 {
 	c->minimum_buffers = n;
 }
-EXPORT_SYMBOL(dm_bufio_set_minimum_buffers);
+EXPORT_SYMBOL_GPL(dm_bufio_set_minimum_buffers);
 
 unsigned dm_bufio_get_block_size(struct dm_bufio_client *c)
 {
···
 	INIT_LIST_HEAD(&c->reserved_buffers);
 	c->need_reserved_buffers = reserved_buffers;
 
-	c->minimum_buffers = DM_BUFIO_MIN_BUFFERS;
+	dm_bufio_set_minimum_buffers(c, DM_BUFIO_MIN_BUFFERS);
 
 	init_waitqueue_head(&c->free_buffer_wait);
 	c->async_write_error = 0;

drivers/md/dm-bufio.h include/linux/dm-bufio.h

···
  * This file is released under the GPL.
  */
 
-#ifndef DM_BUFIO_H
-#define DM_BUFIO_H
+#ifndef _LINUX_DM_BUFIO_H
+#define _LINUX_DM_BUFIO_H
 
 #include <linux/blkdev.h>
 #include <linux/types.h>

drivers/md/dm-integrity.c

···
 #include <crypto/hash.h>
 #include <crypto/skcipher.h>
 #include <linux/async_tx.h>
-#include "dm-bufio.h"
+#include <linux/dm-bufio.h>
 
 #define DM_MSG_PREFIX "integrity"
 

drivers/md/dm-snap-persistent.c

···
 #include <linux/export.h>
 #include <linux/slab.h>
 #include <linux/dm-io.h>
-#include "dm-bufio.h"
+#include <linux/dm-bufio.h>
 
 #define DM_MSG_PREFIX "persistent snapshot"
 #define DM_CHUNK_SIZE_DEFAULT_SECTORS 32	/* 16KB */

drivers/md/dm-verity.h

···
 #ifndef DM_VERITY_H
 #define DM_VERITY_H
 
-#include "dm-bufio.h"
+#include <linux/dm-bufio.h>
 #include <linux/device-mapper.h>
 #include <crypto/hash.h>
 

drivers/md/persistent-data/dm-block-manager.c

···
  */
 #include "dm-block-manager.h"
 #include "dm-persistent-data-internal.h"
-#include "../dm-bufio.h"
 
+#include <linux/dm-bufio.h>
 #include <linux/crc32c.h>
 #include <linux/module.h>
 #include <linux/slab.h>