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authorHeinz Mauelshagen <hjm@redhat.com>2008-04-24 21:43:35 +0100
committerAlasdair G Kergon <agk@redhat.com>2008-04-25 13:26:46 +0100
commit416cd17b1982217bca3dc41b9f00b0b38fdaadad (patch)
treedcb73db9876f5b973ad26b47449083b98efad1b6
parenteb69aca5d3370b81450d68edeebc2bb9a3eb9689 (diff)
dm log: clean interface
Clean up the dm-log interface to prepare for publishing it in include/linux. Signed-off-by: Heinz Mauelshagen <hjm@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
-rw-r--r--drivers/md/dm-log.c89
-rw-r--r--drivers/md/dm-log.h84
-rw-r--r--drivers/md/dm-raid1.c36
-rw-r--r--drivers/md/dm.h6
-rw-r--r--include/linux/device-mapper.h2
5 files changed, 114 insertions, 103 deletions
diff --git a/drivers/md/dm-log.c b/drivers/md/dm-log.c
index 14f785fc308a..b776701cc8fa 100644
--- a/drivers/md/dm-log.c
+++ b/drivers/md/dm-log.c
@@ -12,13 +12,14 @@
#include "dm-log.h"
#include "dm-io.h"
+#include "dm.h"
#define DM_MSG_PREFIX "dirty region log"
static LIST_HEAD(_log_types);
static DEFINE_SPINLOCK(_lock);
-int dm_register_dirty_log_type(struct dirty_log_type *type)
+int dm_dirty_log_type_register(struct dm_dirty_log_type *type)
{
spin_lock(&_lock);
type->use_count = 0;
@@ -27,8 +28,9 @@ int dm_register_dirty_log_type(struct dirty_log_type *type)
return 0;
}
+EXPORT_SYMBOL(dm_dirty_log_type_register);
-int dm_unregister_dirty_log_type(struct dirty_log_type *type)
+int dm_dirty_log_type_unregister(struct dm_dirty_log_type *type)
{
spin_lock(&_lock);
@@ -41,10 +43,11 @@ int dm_unregister_dirty_log_type(struct dirty_log_type *type)
return 0;
}
+EXPORT_SYMBOL(dm_dirty_log_type_unregister);
-static struct dirty_log_type *_get_type(const char *type_name)
+static struct dm_dirty_log_type *_get_type(const char *type_name)
{
- struct dirty_log_type *type;
+ struct dm_dirty_log_type *type;
spin_lock(&_lock);
list_for_each_entry (type, &_log_types, list)
@@ -79,10 +82,10 @@ static struct dirty_log_type *_get_type(const char *type_name)
*
* Returns: dirty_log_type* on success, NULL on failure
*/
-static struct dirty_log_type *get_type(const char *type_name)
+static struct dm_dirty_log_type *get_type(const char *type_name)
{
char *p, *type_name_dup;
- struct dirty_log_type *type;
+ struct dm_dirty_log_type *type;
type = _get_type(type_name);
if (type)
@@ -111,7 +114,7 @@ static struct dirty_log_type *get_type(const char *type_name)
return type;
}
-static void put_type(struct dirty_log_type *type)
+static void put_type(struct dm_dirty_log_type *type)
{
spin_lock(&_lock);
if (!--type->use_count)
@@ -119,11 +122,12 @@ static void put_type(struct dirty_log_type *type)
spin_unlock(&_lock);
}
-struct dirty_log *dm_create_dirty_log(const char *type_name, struct dm_target *ti,
- unsigned int argc, char **argv)
+struct dm_dirty_log *dm_dirty_log_create(const char *type_name,
+ struct dm_target *ti,
+ unsigned int argc, char **argv)
{
- struct dirty_log_type *type;
- struct dirty_log *log;
+ struct dm_dirty_log_type *type;
+ struct dm_dirty_log *log;
log = kmalloc(sizeof(*log), GFP_KERNEL);
if (!log)
@@ -144,13 +148,15 @@ struct dirty_log *dm_create_dirty_log(const char *type_name, struct dm_target *t
return log;
}
+EXPORT_SYMBOL(dm_dirty_log_create);
-void dm_destroy_dirty_log(struct dirty_log *log)
+void dm_dirty_log_destroy(struct dm_dirty_log *log)
{
log->type->dtr(log);
put_type(log->type);
kfree(log);
}
+EXPORT_SYMBOL(dm_dirty_log_destroy);
/*-----------------------------------------------------------------
* Persistent and core logs share a lot of their implementation.
@@ -216,7 +222,7 @@ struct log_c {
* The touched member needs to be updated every time we access
* one of the bitsets.
*/
-static inline int log_test_bit(uint32_t *bs, unsigned bit)
+static inline int log_test_bit(uint32_t *bs, unsigned bit)
{
return ext2_test_bit(bit, (unsigned long *) bs) ? 1 : 0;
}
@@ -303,7 +309,7 @@ static inline int write_header(struct log_c *log)
* argv contains region_size followed optionally by [no]sync
*--------------------------------------------------------------*/
#define BYTE_SHIFT 3
-static int create_log_context(struct dirty_log *log, struct dm_target *ti,
+static int create_log_context(struct dm_dirty_log *log, struct dm_target *ti,
unsigned int argc, char **argv,
struct dm_dev *dev)
{
@@ -435,7 +441,7 @@ static int create_log_context(struct dirty_log *log, struct dm_target *ti,
return 0;
}
-static int core_ctr(struct dirty_log *log, struct dm_target *ti,
+static int core_ctr(struct dm_dirty_log *log, struct dm_target *ti,
unsigned int argc, char **argv)
{
return create_log_context(log, ti, argc, argv, NULL);
@@ -448,7 +454,7 @@ static void destroy_log_context(struct log_c *lc)
kfree(lc);
}
-static void core_dtr(struct dirty_log *log)
+static void core_dtr(struct dm_dirty_log *log)
{
struct log_c *lc = (struct log_c *) log->context;
@@ -461,7 +467,7 @@ static void core_dtr(struct dirty_log *log)
*
* argv contains log_device region_size followed optionally by [no]sync
*--------------------------------------------------------------*/
-static int disk_ctr(struct dirty_log *log, struct dm_target *ti,
+static int disk_ctr(struct dm_dirty_log *log, struct dm_target *ti,
unsigned int argc, char **argv)
{
int r;
@@ -486,7 +492,7 @@ static int disk_ctr(struct dirty_log *log, struct dm_target *ti,
return 0;
}
-static void disk_dtr(struct dirty_log *log)
+static void disk_dtr(struct dm_dirty_log *log)
{
struct log_c *lc = (struct log_c *) log->context;
@@ -515,7 +521,7 @@ static void fail_log_device(struct log_c *lc)
dm_table_event(lc->ti->table);
}
-static int disk_resume(struct dirty_log *log)
+static int disk_resume(struct dm_dirty_log *log)
{
int r;
unsigned i;
@@ -571,38 +577,38 @@ static int disk_resume(struct dirty_log *log)
return r;
}
-static uint32_t core_get_region_size(struct dirty_log *log)
+static uint32_t core_get_region_size(struct dm_dirty_log *log)
{
struct log_c *lc = (struct log_c *) log->context;
return lc->region_size;
}
-static int core_resume(struct dirty_log *log)
+static int core_resume(struct dm_dirty_log *log)
{
struct log_c *lc = (struct log_c *) log->context;
lc->sync_search = 0;
return 0;
}
-static int core_is_clean(struct dirty_log *log, region_t region)
+static int core_is_clean(struct dm_dirty_log *log, region_t region)
{
struct log_c *lc = (struct log_c *) log->context;
return log_test_bit(lc->clean_bits, region);
}
-static int core_in_sync(struct dirty_log *log, region_t region, int block)
+static int core_in_sync(struct dm_dirty_log *log, region_t region, int block)
{
struct log_c *lc = (struct log_c *) log->context;
return log_test_bit(lc->sync_bits, region);
}
-static int core_flush(struct dirty_log *log)
+static int core_flush(struct dm_dirty_log *log)
{
/* no op */
return 0;
}
-static int disk_flush(struct dirty_log *log)
+static int disk_flush(struct dm_dirty_log *log)
{
int r;
struct log_c *lc = (struct log_c *) log->context;
@@ -620,19 +626,19 @@ static int disk_flush(struct dirty_log *log)
return r;
}
-static void core_mark_region(struct dirty_log *log, region_t region)
+static void core_mark_region(struct dm_dirty_log *log, region_t region)
{
struct log_c *lc = (struct log_c *) log->context;
log_clear_bit(lc, lc->clean_bits, region);
}
-static void core_clear_region(struct dirty_log *log, region_t region)
+static void core_clear_region(struct dm_dirty_log *log, region_t region)
{
struct log_c *lc = (struct log_c *) log->context;
log_set_bit(lc, lc->clean_bits, region);
}
-static int core_get_resync_work(struct dirty_log *log, region_t *region)
+static int core_get_resync_work(struct dm_dirty_log *log, region_t *region)
{
struct log_c *lc = (struct log_c *) log->context;
@@ -655,7 +661,7 @@ static int core_get_resync_work(struct dirty_log *log, region_t *region)
return 1;
}
-static void core_set_region_sync(struct dirty_log *log, region_t region,
+static void core_set_region_sync(struct dm_dirty_log *log, region_t region,
int in_sync)
{
struct log_c *lc = (struct log_c *) log->context;
@@ -670,7 +676,7 @@ static void core_set_region_sync(struct dirty_log *log, region_t region,
}
}
-static region_t core_get_sync_count(struct dirty_log *log)
+static region_t core_get_sync_count(struct dm_dirty_log *log)
{
struct log_c *lc = (struct log_c *) log->context;
@@ -681,7 +687,7 @@ static region_t core_get_sync_count(struct dirty_log *log)
if (lc->sync != DEFAULTSYNC) \
DMEMIT("%ssync ", lc->sync == NOSYNC ? "no" : "")
-static int core_status(struct dirty_log *log, status_type_t status,
+static int core_status(struct dm_dirty_log *log, status_type_t status,
char *result, unsigned int maxlen)
{
int sz = 0;
@@ -701,7 +707,7 @@ static int core_status(struct dirty_log *log, status_type_t status,
return sz;
}
-static int disk_status(struct dirty_log *log, status_type_t status,
+static int disk_status(struct dm_dirty_log *log, status_type_t status,
char *result, unsigned int maxlen)
{
int sz = 0;
@@ -723,7 +729,7 @@ static int disk_status(struct dirty_log *log, status_type_t status,
return sz;
}
-static struct dirty_log_type _core_type = {
+static struct dm_dirty_log_type _core_type = {
.name = "core",
.module = THIS_MODULE,
.ctr = core_ctr,
@@ -741,7 +747,7 @@ static struct dirty_log_type _core_type = {
.status = core_status,
};
-static struct dirty_log_type _disk_type = {
+static struct dm_dirty_log_type _disk_type = {
.name = "disk",
.module = THIS_MODULE,
.ctr = disk_ctr,
@@ -764,14 +770,14 @@ int __init dm_dirty_log_init(void)
{
int r;
- r = dm_register_dirty_log_type(&_core_type);
+ r = dm_dirty_log_type_register(&_core_type);
if (r)
DMWARN("couldn't register core log");
- r = dm_register_dirty_log_type(&_disk_type);
+ r = dm_dirty_log_type_register(&_disk_type);
if (r) {
DMWARN("couldn't register disk type");
- dm_unregister_dirty_log_type(&_core_type);
+ dm_dirty_log_type_unregister(&_core_type);
}
return r;
@@ -779,15 +785,10 @@ int __init dm_dirty_log_init(void)
void __exit dm_dirty_log_exit(void)
{
- dm_unregister_dirty_log_type(&_disk_type);
- dm_unregister_dirty_log_type(&_core_type);
+ dm_dirty_log_type_unregister(&_disk_type);
+ dm_dirty_log_type_unregister(&_core_type);
}
-EXPORT_SYMBOL(dm_register_dirty_log_type);
-EXPORT_SYMBOL(dm_unregister_dirty_log_type);
-EXPORT_SYMBOL(dm_create_dirty_log);
-EXPORT_SYMBOL(dm_destroy_dirty_log);
-
module_init(dm_dirty_log_init);
module_exit(dm_dirty_log_exit);
diff --git a/drivers/md/dm-log.h b/drivers/md/dm-log.h
index 3fae87eb5963..2da48a857cb9 100644
--- a/drivers/md/dm-log.h
+++ b/drivers/md/dm-log.h
@@ -1,52 +1,58 @@
/*
* Copyright (C) 2003 Sistina Software
+ * Copyright (C) 2004-2008 Red Hat, Inc. All rights reserved.
+ *
+ * Device-Mapper dirty region log.
*
* This file is released under the LGPL.
*/
-#ifndef DM_DIRTY_LOG
-#define DM_DIRTY_LOG
+#ifndef _LINUX_DM_DIRTY_LOG
+#define _LINUX_DM_DIRTY_LOG
+
+#ifdef __KERNEL__
-#include "dm.h"
+#include <linux/types.h>
+#include <linux/device-mapper.h>
typedef sector_t region_t;
-struct dirty_log_type;
+struct dm_dirty_log_type;
-struct dirty_log {
- struct dirty_log_type *type;
+struct dm_dirty_log {
+ struct dm_dirty_log_type *type;
void *context;
};
-struct dirty_log_type {
+struct dm_dirty_log_type {
struct list_head list;
const char *name;
struct module *module;
- unsigned int use_count;
+ unsigned use_count;
- int (*ctr)(struct dirty_log *log, struct dm_target *ti,
- unsigned int argc, char **argv);
- void (*dtr)(struct dirty_log *log);
+ int (*ctr)(struct dm_dirty_log *log, struct dm_target *ti,
+ unsigned argc, char **argv);
+ void (*dtr)(struct dm_dirty_log *log);
/*
* There are times when we don't want the log to touch
* the disk.
*/
- int (*presuspend)(struct dirty_log *log);
- int (*postsuspend)(struct dirty_log *log);
- int (*resume)(struct dirty_log *log);
+ int (*presuspend)(struct dm_dirty_log *log);
+ int (*postsuspend)(struct dm_dirty_log *log);
+ int (*resume)(struct dm_dirty_log *log);
/*
* Retrieves the smallest size of region that the log can
* deal with.
*/
- uint32_t (*get_region_size)(struct dirty_log *log);
+ uint32_t (*get_region_size)(struct dm_dirty_log *log);
- /*
+ /*
* A predicate to say whether a region is clean or not.
* May block.
*/
- int (*is_clean)(struct dirty_log *log, region_t region);
+ int (*is_clean)(struct dm_dirty_log *log, region_t region);
/*
* Returns: 0, 1, -EWOULDBLOCK, < 0
@@ -59,13 +65,14 @@ struct dirty_log_type {
* passed to a daemon to deal with, since a daemon is
* allowed to block.
*/
- int (*in_sync)(struct dirty_log *log, region_t region, int can_block);
+ int (*in_sync)(struct dm_dirty_log *log, region_t region,
+ int can_block);
/*
* Flush the current log state (eg, to disk). This
* function may block.
*/
- int (*flush)(struct dirty_log *log);
+ int (*flush)(struct dm_dirty_log *log);
/*
* Mark an area as clean or dirty. These functions may
@@ -73,8 +80,8 @@ struct dirty_log_type {
* be extremely rare (eg, allocating another chunk of
* memory for some reason).
*/
- void (*mark_region)(struct dirty_log *log, region_t region);
- void (*clear_region)(struct dirty_log *log, region_t region);
+ void (*mark_region)(struct dm_dirty_log *log, region_t region);
+ void (*clear_region)(struct dm_dirty_log *log, region_t region);
/*
* Returns: <0 (error), 0 (no region), 1 (region)
@@ -88,44 +95,39 @@ struct dirty_log_type {
* tells you if an area is synchronised, the other
* assigns recovery work.
*/
- int (*get_resync_work)(struct dirty_log *log, region_t *region);
+ int (*get_resync_work)(struct dm_dirty_log *log, region_t *region);
/*
* This notifies the log that the resync status of a region
* has changed. It also clears the region from the recovering
* list (if present).
*/
- void (*set_region_sync)(struct dirty_log *log,
+ void (*set_region_sync)(struct dm_dirty_log *log,
region_t region, int in_sync);
- /*
+ /*
* Returns the number of regions that are in sync.
- */
- region_t (*get_sync_count)(struct dirty_log *log);
+ */
+ region_t (*get_sync_count)(struct dm_dirty_log *log);
/*
* Support function for mirror status requests.
*/
- int (*status)(struct dirty_log *log, status_type_t status_type,
- char *result, unsigned int maxlen);
+ int (*status)(struct dm_dirty_log *log, status_type_t status_type,
+ char *result, unsigned maxlen);
};
-int dm_register_dirty_log_type(struct dirty_log_type *type);
-int dm_unregister_dirty_log_type(struct dirty_log_type *type);
-
+int dm_dirty_log_type_register(struct dm_dirty_log_type *type);
+int dm_dirty_log_type_unregister(struct dm_dirty_log_type *type);
/*
* Make sure you use these two functions, rather than calling
* type->constructor/destructor() directly.
*/
-struct dirty_log *dm_create_dirty_log(const char *type_name, struct dm_target *ti,
- unsigned int argc, char **argv);
-void dm_destroy_dirty_log(struct dirty_log *log);
-
-/*
- * init/exit functions.
- */
-int dm_dirty_log_init(void);
-void dm_dirty_log_exit(void);
+struct dm_dirty_log *dm_dirty_log_create(const char *type_name,
+ struct dm_target *ti,
+ unsigned argc, char **argv);
+void dm_dirty_log_destroy(struct dm_dirty_log *log);
-#endif
+#endif /* __KERNEL__ */
+#endif /* _LINUX_DM_DIRTY_LOG_H */
diff --git a/drivers/md/dm-raid1.c b/drivers/md/dm-raid1.c
index 32c7c6d10939..5beeced4e522 100644
--- a/drivers/md/dm-raid1.c
+++ b/drivers/md/dm-raid1.c
@@ -74,7 +74,7 @@ struct region_hash {
unsigned region_shift;
/* holds persistent region state */
- struct dirty_log *log;
+ struct dm_dirty_log *log;
/* hash table */
rwlock_t hash_lock;
@@ -184,7 +184,7 @@ static void queue_bio(struct mirror_set *ms, struct bio *bio, int rw);
#define MIN_REGIONS 64
#define MAX_RECOVERY 1
static int rh_init(struct region_hash *rh, struct mirror_set *ms,
- struct dirty_log *log, uint32_t region_size,
+ struct dm_dirty_log *log, uint32_t region_size,
region_t nr_regions)
{
unsigned int nr_buckets, max_buckets;
@@ -249,7 +249,7 @@ static void rh_exit(struct region_hash *rh)
}
if (rh->log)
- dm_destroy_dirty_log(rh->log);
+ dm_dirty_log_destroy(rh->log);
if (rh->region_pool)
mempool_destroy(rh->region_pool);
vfree(rh->buckets);
@@ -831,7 +831,7 @@ static void do_recovery(struct mirror_set *ms)
{
int r;
struct region *reg;
- struct dirty_log *log = ms->rh.log;
+ struct dm_dirty_log *log = ms->rh.log;
/*
* Start quiescing some regions.
@@ -1017,7 +1017,7 @@ static void __bio_mark_nosync(struct mirror_set *ms,
{
unsigned long flags;
struct region_hash *rh = &ms->rh;
- struct dirty_log *log = ms->rh.log;
+ struct dm_dirty_log *log = ms->rh.log;
struct region *reg;
region_t region = bio_to_region(rh, bio);
int recovering = 0;
@@ -1301,7 +1301,7 @@ static void do_mirror(struct work_struct *work)
static struct mirror_set *alloc_context(unsigned int nr_mirrors,
uint32_t region_size,
struct dm_target *ti,
- struct dirty_log *dl)
+ struct dm_dirty_log *dl)
{
size_t len;
struct mirror_set *ms = NULL;
@@ -1401,12 +1401,12 @@ static int get_mirror(struct mirror_set *ms, struct dm_target *ti,
/*
* Create dirty log: log_type #log_params <log_params>
*/
-static struct dirty_log *create_dirty_log(struct dm_target *ti,
+static struct dm_dirty_log *create_dirty_log(struct dm_target *ti,
unsigned int argc, char **argv,
unsigned int *args_used)
{
unsigned int param_count;
- struct dirty_log *dl;
+ struct dm_dirty_log *dl;
if (argc < 2) {
ti->error = "Insufficient mirror log arguments";
@@ -1425,7 +1425,7 @@ static struct dirty_log *create_dirty_log(struct dm_target *ti,
return NULL;
}
- dl = dm_create_dirty_log(argv[0], ti, param_count, argv + 2);
+ dl = dm_dirty_log_create(argv[0], ti, param_count, argv + 2);
if (!dl) {
ti->error = "Error creating mirror dirty log";
return NULL;
@@ -1433,7 +1433,7 @@ static struct dirty_log *create_dirty_log(struct dm_target *ti,
if (!_check_region_size(ti, dl->type->get_region_size(dl))) {
ti->error = "Invalid region size";
- dm_destroy_dirty_log(dl);
+ dm_dirty_log_destroy(dl);
return NULL;
}
@@ -1494,7 +1494,7 @@ static int mirror_ctr(struct dm_target *ti, unsigned int argc, char **argv)
int r;
unsigned int nr_mirrors, m, args_used;
struct mirror_set *ms;
- struct dirty_log *dl;
+ struct dm_dirty_log *dl;
dl = create_dirty_log(ti, argc, argv, &args_used);
if (!dl)
@@ -1506,7 +1506,7 @@ static int mirror_ctr(struct dm_target *ti, unsigned int argc, char **argv)
if (!argc || sscanf(argv[0], "%u", &nr_mirrors) != 1 ||
nr_mirrors < 2 || nr_mirrors > DM_KCOPYD_MAX_REGIONS + 1) {
ti->error = "Invalid number of mirrors";
- dm_destroy_dirty_log(dl);
+ dm_dirty_log_destroy(dl);
return -EINVAL;
}
@@ -1514,13 +1514,13 @@ static int mirror_ctr(struct dm_target *ti, unsigned int argc, char **argv)
if (argc < nr_mirrors * 2) {
ti->error = "Too few mirror arguments";
- dm_destroy_dirty_log(dl);
+ dm_dirty_log_destroy(dl);
return -EINVAL;
}
ms = alloc_context(nr_mirrors, dl->type->get_region_size(dl), ti, dl);
if (!ms) {
- dm_destroy_dirty_log(dl);
+ dm_dirty_log_destroy(dl);
return -ENOMEM;
}
@@ -1732,7 +1732,7 @@ out:
static void mirror_presuspend(struct dm_target *ti)
{
struct mirror_set *ms = (struct mirror_set *) ti->private;
- struct dirty_log *log = ms->rh.log;
+ struct dm_dirty_log *log = ms->rh.log;
atomic_set(&ms->suspend, 1);
@@ -1761,7 +1761,7 @@ static void mirror_presuspend(struct dm_target *ti)
static void mirror_postsuspend(struct dm_target *ti)
{
struct mirror_set *ms = ti->private;
- struct dirty_log *log = ms->rh.log;
+ struct dm_dirty_log *log = ms->rh.log;
if (log->type->postsuspend && log->type->postsuspend(log))
/* FIXME: need better error handling */
@@ -1771,7 +1771,7 @@ static void mirror_postsuspend(struct dm_target *ti)
static void mirror_resume(struct dm_target *ti)
{
struct mirror_set *ms = ti->private;
- struct dirty_log *log = ms->rh.log;
+ struct dm_dirty_log *log = ms->rh.log;
atomic_set(&ms->suspend, 0);
if (log->type->resume && log->type->resume(log))
@@ -1809,7 +1809,7 @@ static int mirror_status(struct dm_target *ti, status_type_t type,
{
unsigned int m, sz = 0;
struct mirror_set *ms = (struct mirror_set *) ti->private;
- struct dirty_log *log = ms->rh.log;
+ struct dm_dirty_log *log = ms->rh.log;
char buffer[ms->nr_mirrors + 1];
switch (type) {
diff --git a/drivers/md/dm.h b/drivers/md/dm.h
index b4584a39383b..17f2d6a8b124 100644
--- a/drivers/md/dm.h
+++ b/drivers/md/dm.h
@@ -189,4 +189,10 @@ int dm_lock_for_deletion(struct mapped_device *md);
void dm_kobject_uevent(struct mapped_device *md);
+/*
+ * Dirty log
+ */
+int dm_dirty_log_init(void);
+void dm_dirty_log_exit(void);
+
#endif
diff --git a/include/linux/device-mapper.h b/include/linux/device-mapper.h
index cb784579956b..4db23378cfb1 100644
--- a/include/linux/device-mapper.h
+++ b/include/linux/device-mapper.h
@@ -10,6 +10,8 @@
#ifdef __KERNEL__
+#include <linux/bio.h>
+
struct dm_target;
struct dm_table;
struct dm_dev;