[PATCH] dm: add exports

Move definitions of core device-mapper functions for manipulating mapped
devices and their tables to <linux/device-mapper.h> advertising their
availability for use elsewhere in the kernel.

Protect the contents of device-mapper.h with ifdef __KERNEL__. And throw
in a few formatting clean-ups and extra comments.

Signed-off-by: Alasdair G Kergon <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>
Signed-off-by: Linus Torvalds <[e-mail]>

drivers/md/dm.c

···
 
 union map_info *dm_get_mapinfo(struct bio *bio)
 {
-        if (bio && bio->bi_private)
-                return &((struct target_io *)bio->bi_private)->info;
-        return NULL;
+	if (bio && bio->bi_private)
+		return &((struct target_io *)bio->bi_private)->info;
+	return NULL;
 }
 
 #define MINOR_ALLOCED ((void *)-1)
···
 	if (r > 0) {
 		/* the bio has been remapped so dispatch it */
 
-		blk_add_trace_remap(bdev_get_queue(clone->bi_bdev), clone, 
-				    tio->io->bio->bi_bdev->bd_dev, sector, 
+		blk_add_trace_remap(bdev_get_queue(clone->bi_bdev), clone,
+				    tio->io->bio->bi_bdev->bd_dev, sector,
 				    clone->bi_sector);
 
 		generic_make_request(clone);
···
 	md = idr_find(&_minor_idr, minor);
 	if (md && (md == MINOR_ALLOCED ||
 		   (dm_disk(md)->first_minor != minor) ||
-	           test_bit(DMF_FREEING, &md->flags))) {
+		   test_bit(DMF_FREEING, &md->flags))) {
 		md = NULL;
 		goto out;
 	}

drivers/md/dm.h

···
 };
 
 struct dm_table;
-struct mapped_device;
 
 /*-----------------------------------------------------------------
- * Functions for manipulating a struct mapped_device.
- * Drop the reference with dm_put when you finish with the object.
+ * Internal table functions.
  *---------------------------------------------------------------*/
-
-/*
- * DM_ANY_MINOR allocates any available minor number.
- */
-#define DM_ANY_MINOR (-1)
-int dm_create(int minor, struct mapped_device **md);
-
-void dm_set_mdptr(struct mapped_device *md, void *ptr);
-void *dm_get_mdptr(struct mapped_device *md);
-
-/*
- * Reference counting for md.
- */
-void dm_get(struct mapped_device *md);
-struct mapped_device *dm_get_md(dev_t dev);
-void dm_put(struct mapped_device *md);
-
-/*
- * A device can still be used while suspended, but I/O is deferred.
- */
-int dm_suspend(struct mapped_device *md, int with_lockfs);
-int dm_resume(struct mapped_device *md);
-
-/*
- * The device must be suspended before calling this method.
- */
-int dm_swap_table(struct mapped_device *md, struct dm_table *t);
-
-/*
- * Drop a reference on the table when you've finished with the
- * result.
- */
-struct dm_table *dm_get_table(struct mapped_device *md);
-
-/*
- * Event functions.
- */
-uint32_t dm_get_event_nr(struct mapped_device *md);
-int dm_wait_event(struct mapped_device *md, int event_nr);
-
-/*
- * Info functions.
- */
-struct gendisk *dm_disk(struct mapped_device *md);
-int dm_suspended(struct mapped_device *md);
-
-/*
- * Geometry functions.
- */
-int dm_get_geometry(struct mapped_device *md, struct hd_geometry *geo);
-int dm_set_geometry(struct mapped_device *md, struct hd_geometry *geo);
-
-/*-----------------------------------------------------------------
- * Functions for manipulating a table.  Tables are also reference
- * counted.
- *---------------------------------------------------------------*/
-int dm_table_create(struct dm_table **result, int mode,
-		    unsigned num_targets, struct mapped_device *md);
-
-void dm_table_get(struct dm_table *t);
-void dm_table_put(struct dm_table *t);
-
-int dm_table_add_target(struct dm_table *t, const char *type,
-			sector_t start,	sector_t len, char *params);
-int dm_table_complete(struct dm_table *t);
 void dm_table_event_callback(struct dm_table *t,
 			     void (*fn)(void *), void *context);
-void dm_table_event(struct dm_table *t);
-sector_t dm_table_get_size(struct dm_table *t);
 struct dm_target *dm_table_get_target(struct dm_table *t, unsigned int index);
 struct dm_target *dm_table_find_target(struct dm_table *t, sector_t sector);
 void dm_table_set_restrictions(struct dm_table *t, struct request_queue *q);
-unsigned int dm_table_get_num_targets(struct dm_table *t);
 struct list_head *dm_table_get_devices(struct dm_table *t);
-int dm_table_get_mode(struct dm_table *t);
-struct mapped_device *dm_table_get_md(struct dm_table *t);
 void dm_table_presuspend_targets(struct dm_table *t);
 void dm_table_postsuspend_targets(struct dm_table *t);
 void dm_table_resume_targets(struct dm_table *t);
···
 void dm_put_target_type(struct target_type *t);
 int dm_target_iterate(void (*iter_func)(struct target_type *tt,
 					void *param), void *param);
-
 
 /*-----------------------------------------------------------------
  * Useful inlines.

include/linux/device-mapper.h

···
 #ifndef _LINUX_DEVICE_MAPPER_H
 #define _LINUX_DEVICE_MAPPER_H
 
+#ifdef __KERNEL__
+
 struct dm_target;
 struct dm_table;
 struct dm_dev;
+struct mapped_device;
 
 typedef enum { STATUSTYPE_INFO, STATUSTYPE_TABLE } status_type_t;
 
···
 struct target_type {
 	const char *name;
 	struct module *module;
-        unsigned version[3];
+	unsigned version[3];
 	dm_ctr_fn ctr;
 	dm_dtr_fn dtr;
 	dm_map_fn map;
···
 int dm_register_target(struct target_type *t);
 int dm_unregister_target(struct target_type *t);
 
-#endif				/* _LINUX_DEVICE_MAPPER_H */
+
+/*-----------------------------------------------------------------
+ * Functions for creating and manipulating mapped devices.
+ * Drop the reference with dm_put when you finish with the object.
+ *---------------------------------------------------------------*/
+
+/*
+ * DM_ANY_MINOR chooses the next available minor number.
+ */
+#define DM_ANY_MINOR (-1)
+int dm_create(int minor, struct mapped_device **md);
+
+/*
+ * Reference counting for md.
+ */
+struct mapped_device *dm_get_md(dev_t dev);
+void dm_get(struct mapped_device *md);
+void dm_put(struct mapped_device *md);
+
+/*
+ * An arbitrary pointer may be stored alongside a mapped device.
+ */
+void dm_set_mdptr(struct mapped_device *md, void *ptr);
+void *dm_get_mdptr(struct mapped_device *md);
+
+/*
+ * A device can still be used while suspended, but I/O is deferred.
+ */
+int dm_suspend(struct mapped_device *md, int with_lockfs);
+int dm_resume(struct mapped_device *md);
+
+/*
+ * Event functions.
+ */
+uint32_t dm_get_event_nr(struct mapped_device *md);
+int dm_wait_event(struct mapped_device *md, int event_nr);
+
+/*
+ * Info functions.
+ */
+struct gendisk *dm_disk(struct mapped_device *md);
+int dm_suspended(struct mapped_device *md);
+
+/*
+ * Geometry functions.
+ */
+int dm_get_geometry(struct mapped_device *md, struct hd_geometry *geo);
+int dm_set_geometry(struct mapped_device *md, struct hd_geometry *geo);
+
+
+/*-----------------------------------------------------------------
+ * Functions for manipulating device-mapper tables.
+ *---------------------------------------------------------------*/
+
+/*
+ * First create an empty table.
+ */
+int dm_table_create(struct dm_table **result, int mode,
+		    unsigned num_targets, struct mapped_device *md);
+
+/*
+ * Then call this once for each target.
+ */
+int dm_table_add_target(struct dm_table *t, const char *type,
+			sector_t start, sector_t len, char *params);
+
+/*
+ * Finally call this to make the table ready for use.
+ */
+int dm_table_complete(struct dm_table *t);
+
+/*
+ * Table reference counting.
+ */
+struct dm_table *dm_get_table(struct mapped_device *md);
+void dm_table_get(struct dm_table *t);
+void dm_table_put(struct dm_table *t);
+
+/*
+ * Queries
+ */
+sector_t dm_table_get_size(struct dm_table *t);
+unsigned int dm_table_get_num_targets(struct dm_table *t);
+int dm_table_get_mode(struct dm_table *t);
+struct mapped_device *dm_table_get_md(struct dm_table *t);
+
+/*
+ * Trigger an event.
+ */
+void dm_table_event(struct dm_table *t);
+
+/*
+ * The device must be suspended before calling this method.
+ */
+int dm_swap_table(struct mapped_device *md, struct dm_table *t);
+
+#endif	/* __KERNEL__ */
+#endif	/* _LINUX_DEVICE_MAPPER_H */