dm: move target request nr to dm_target_io

This patch moves target_request_nr from map_info to dm_target_io and
makes it accessible with dm_bio_get_target_request_nr.

This patch is a preparation for the next patch that removes map_info.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>

1 files changed, 10 insertions, 4 deletions

diff --git a/include/linux/device-mapper.h b/include/linux/device-mapper.h
index 6f0e73b4a80d..eb96ef6fd8b7 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;
 };
 
 /*
@@ -193,20 +192,21 @@ 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;
 
@@ -263,6 +263,7 @@ struct dm_target_io {
         struct dm_io *io;
         struct dm_target *ti;
         union map_info info;
+        unsigned target_request_nr;
         struct bio clone;
 };
 
@@ -276,6 +277,11 @@ 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);