This patch defines new methods for targets which uses
request-based device-mapper:
- prep_map : Decide a destination device for the request
and return the information to dm core.
Also, allocate target internal data if needed.
- free_context : Free target internal data.
Called when error occurs before dispatching.
- map_rq : Map the clone to the device decided in prep_map
- rq_end_io_first : Check errors of the clone and store internal
information in target internal data to pass
rq_end_io if needed.
- rq_end_io : Free target internal data.
Also, struct dm_map_info is added to pass information between
dm_prep_map_fn() and dm_map_request_fn().
Signed-off-by: Kiyoshi Ueda <[email protected]>
Signed-off-by: Jun'ichi Nomura <[email protected]>
diff -rupN 5-core-init/drivers/md/dm.h 6-add-target-func/drivers/md/dm.h
--- 5-core-init/drivers/md/dm.h 2006-12-15 10:26:43.000000000 -0500
+++ 6-add-target-func/drivers/md/dm.h 2006-12-15 10:42:49.000000000 -0500
@@ -49,6 +49,16 @@ struct dm_dev {
char name[16];
};
+/*
+ * Device vector to specify mapping destinations.
+ * Target make this vector in prep_map function.
+ */
+struct dm_map_info {
+// unsigned num_devs;
+ struct block_device *devs;
+ union map_info map_context;
+};
+
struct dm_table;
/*-----------------------------------------------------------------
diff -rupN 5-core-init/include/linux/device-mapper.h 6-add-target-func/include/linux/device-mapper.h
--- 5-core-init/include/linux/device-mapper.h 2006-12-15 10:24:52.000000000 -0500
+++ 6-add-target-func/include/linux/device-mapper.h 2006-12-15 10:42:49.000000000 -0500
@@ -10,6 +10,9 @@
#ifdef __KERNEL__
+struct request;
+struct request_queue;
+struct dm_map_info;
struct dm_target;
struct dm_table;
struct dm_dev;
@@ -44,6 +47,15 @@ typedef void (*dm_dtr_fn) (struct dm_tar
typedef int (*dm_map_fn) (struct dm_target *ti, struct bio *bio,
union map_info *map_context);
+typedef int (*dm_prep_map_fn) (struct dm_target *ti, struct request *rq,
+ struct request_queue *q);
+
+typedef int (*dm_map_request_fn) (struct dm_target *ti, struct request *clone,
+ union map_info *map_context,
+ struct dm_map_info *mi);
+
+typedef void (*dm_free_context_fn) (struct dm_target *ti, struct request *rq);
+
/*
* Returns:
* < 0 : error (currently ignored)
@@ -55,6 +67,14 @@ typedef int (*dm_endio_fn) (struct dm_ta
struct bio *bio, int error,
union map_info *map_context);
+typedef int (*dm_request_endio_first_fn) (struct dm_target *ti,
+ struct request *clone, int uptodate,
+ union map_info *map_context);
+
+typedef int (*dm_request_endio_fn) (struct dm_target *ti,
+ struct request *clone, int error,
+ union map_info *map_context);
+
typedef void (*dm_flush_fn) (struct dm_target *ti);
typedef void (*dm_presuspend_fn) (struct dm_target *ti);
typedef void (*dm_postsuspend_fn) (struct dm_target *ti);
@@ -96,7 +116,12 @@ struct target_type {
dm_ctr_fn ctr;
dm_dtr_fn dtr;
dm_map_fn map;
+ dm_prep_map_fn prep_map;
+ dm_map_request_fn map_rq;
+ dm_free_context_fn free_context;
dm_endio_fn end_io;
+ dm_request_endio_first_fn rq_end_io_first;
+ dm_request_endio_fn rq_end_io;
dm_flush_fn flush;
dm_presuspend_fn presuspend;
dm_postsuspend_fn postsuspend;