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Diffstat (limited to 'include/linux/device-mapper.h')
-rw-r--r--include/linux/device-mapper.h55
1 files changed, 47 insertions, 8 deletions
diff --git a/include/linux/device-mapper.h b/include/linux/device-mapper.h
index 38d27a10aa5d..bf6afa2fc432 100644
--- a/include/linux/device-mapper.h
+++ b/include/linux/device-mapper.h
@@ -23,7 +23,6 @@ typedef enum { STATUSTYPE_INFO, STATUSTYPE_TABLE } status_type_t;
union map_info {
void *ptr;
unsigned long long ll;
- unsigned target_request_nr;
};
/*
@@ -46,8 +45,7 @@ typedef void (*dm_dtr_fn) (struct dm_target *ti);
* = 1: simple remap complete
* = 2: The target wants to push back the io
*/
-typedef int (*dm_map_fn) (struct dm_target *ti, struct bio *bio,
- union map_info *map_context);
+typedef int (*dm_map_fn) (struct dm_target *ti, struct bio *bio);
typedef int (*dm_map_request_fn) (struct dm_target *ti, struct request *clone,
union map_info *map_context);
@@ -60,8 +58,7 @@ typedef int (*dm_map_request_fn) (struct dm_target *ti, struct request *clone,
* 2 : The target wants to push back the io
*/
typedef int (*dm_endio_fn) (struct dm_target *ti,
- struct bio *bio, int error,
- union map_info *map_context);
+ struct bio *bio, int error);
typedef int (*dm_request_endio_fn) (struct dm_target *ti,
struct request *clone, int error,
union map_info *map_context);
@@ -193,18 +190,30 @@ struct dm_target {
* A number of zero-length barrier requests that will be submitted
* to the target for the purpose of flushing cache.
*
- * The request number will be placed in union map_info->target_request_nr.
+ * The request number can be accessed with dm_bio_get_target_request_nr.
* It is a responsibility of the target driver to remap these requests
* to the real underlying devices.
*/
unsigned num_flush_requests;
/*
- * The number of discard requests that will be submitted to the
- * target. map_info->request_nr is used just like num_flush_requests.
+ * The number of discard requests that will be submitted to the target.
+ * The request number can be accessed with dm_bio_get_target_request_nr.
*/
unsigned num_discard_requests;
+ /*
+ * The number of WRITE SAME requests that will be submitted to the target.
+ * The request number can be accessed with dm_bio_get_target_request_nr.
+ */
+ unsigned num_write_same_requests;
+
+ /*
+ * The minimum number of extra bytes allocated in each bio for the
+ * target to use. dm_per_bio_data returns the data location.
+ */
+ unsigned per_bio_data_size;
+
/* target specific data */
void *private;
@@ -241,6 +250,36 @@ struct dm_target_callbacks {
int (*congested_fn) (struct dm_target_callbacks *, int);
};
+/*
+ * For bio-based dm.
+ * One of these is allocated for each bio.
+ * This structure shouldn't be touched directly by target drivers.
+ * It is here so that we can inline dm_per_bio_data and
+ * dm_bio_from_per_bio_data
+ */
+struct dm_target_io {
+ struct dm_io *io;
+ struct dm_target *ti;
+ union map_info info;
+ unsigned target_request_nr;
+ struct bio clone;
+};
+
+static inline void *dm_per_bio_data(struct bio *bio, size_t data_size)
+{
+ return (char *)bio - offsetof(struct dm_target_io, clone) - data_size;
+}
+
+static inline struct bio *dm_bio_from_per_bio_data(void *data, size_t data_size)
+{
+ return (struct bio *)((char *)data + data_size + offsetof(struct dm_target_io, clone));
+}
+
+static inline unsigned dm_bio_get_target_request_nr(const struct bio *bio)
+{
+ return container_of(bio, struct dm_target_io, clone)->target_request_nr;
+}
+
int dm_register_target(struct target_type *t);
void dm_unregister_target(struct target_type *t);