diff options
Diffstat (limited to 'include/linux/device-mapper.h')
| -rw-r--r-- | include/linux/device-mapper.h | 86 |
1 files changed, 70 insertions, 16 deletions
diff --git a/include/linux/device-mapper.h b/include/linux/device-mapper.h index 38d27a10aa5d..1e483fa7afb4 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); @@ -71,8 +68,8 @@ typedef void (*dm_postsuspend_fn) (struct dm_target *ti); typedef int (*dm_preresume_fn) (struct dm_target *ti); typedef void (*dm_resume_fn) (struct dm_target *ti); -typedef int (*dm_status_fn) (struct dm_target *ti, status_type_t status_type, - unsigned status_flags, char *result, unsigned maxlen); +typedef void (*dm_status_fn) (struct dm_target *ti, status_type_t status_type, + unsigned status_flags, char *result, unsigned maxlen); typedef int (*dm_message_fn) (struct dm_target *ti, unsigned argc, char **argv); @@ -178,6 +175,14 @@ struct target_type { #define DM_TARGET_IMMUTABLE 0x00000004 #define dm_target_is_immutable(type) ((type)->features & DM_TARGET_IMMUTABLE) +/* + * Some targets need to be sent the same WRITE bio severals times so + * that they can send copies of it to different devices. This function + * examines any supplied bio and returns the number of copies of it the + * target requires. + */ +typedef unsigned (*dm_num_write_bios_fn) (struct dm_target *ti, struct bio *bio); + struct dm_target { struct dm_table *table; struct target_type *type; @@ -190,20 +195,39 @@ struct dm_target { uint32_t max_io_len; /* - * A number of zero-length barrier requests that will be submitted + * A number of zero-length barrier bios 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. - * It is a responsibility of the target driver to remap these requests + * The bio number can be accessed with dm_bio_get_target_bio_nr. + * It is a responsibility of the target driver to remap these bios * to the real underlying devices. */ - unsigned num_flush_requests; + unsigned num_flush_bios; /* - * 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 bios that will be submitted to the target. + * The bio number can be accessed with dm_bio_get_target_bio_nr. */ - unsigned num_discard_requests; + unsigned num_discard_bios; + + /* + * The number of WRITE SAME bios that will be submitted to the target. + * The bio number can be accessed with dm_bio_get_target_bio_nr. + */ + unsigned num_write_same_bios; + + /* + * 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; + + /* + * If defined, this function is called to find out how many + * duplicate bios should be sent to the target when writing + * data. + */ + dm_num_write_bios_fn num_write_bios; /* target specific data */ void *private; @@ -224,10 +248,10 @@ struct dm_target { bool discards_supported:1; /* - * Set if the target required discard request to be split + * Set if the target required discard bios to be split * on max_io_len boundary. */ - bool split_discard_requests:1; + bool split_discard_bios:1; /* * Set if this target does not return zeroes on discarded blocks. @@ -241,6 +265,36 @@ 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_bio_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_bio_nr(const struct bio *bio) +{ + return container_of(bio, struct dm_target_io, clone)->target_bio_nr; +} + int dm_register_target(struct target_type *t); void dm_unregister_target(struct target_type *t); |