dm: rename bio cloning functions
Alasdair G Kergon [Fri, 1 Mar 2013 22:45:47 +0000 (22:45 +0000)]
Rename functions involved in splitting and cloning bios.

The sequence of functions is now:
  (1) __split_and_process* - entry point that selects the processing strategy
  (2) __send* - prepare the details for each bio needed and loop through them
  (3) __clone_and_map* - creates a clone and maps it

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

drivers/md/dm.c

index caef71b..02079cf 100644 (file)
@@ -1061,9 +1061,9 @@ static void clone_bio_integrity(struct bio *bio, struct bio *clone,
 /*
  * Creates a little bio that just does part of a bvec.
  */
-static void split_bvec(struct dm_target_io *tio, struct bio *bio,
-                      sector_t sector, unsigned short idx, unsigned int offset,
-                      unsigned int len)
+static void clone_split_bio(struct dm_target_io *tio, struct bio *bio,
+                           sector_t sector, unsigned short idx,
+                           unsigned offset, unsigned len)
 {
        struct bio *clone = &tio->clone;
        struct bio_vec *bv = bio->bi_io_vec + idx;
@@ -1119,8 +1119,9 @@ static struct dm_target_io *alloc_tio(struct clone_info *ci,
        return tio;
 }
 
-static void __issue_target_request(struct clone_info *ci, struct dm_target *ti,
-                                  unsigned target_bio_nr, sector_t len)
+static void __clone_and_map_simple_bio(struct clone_info *ci,
+                                      struct dm_target *ti,
+                                      unsigned target_bio_nr, sector_t len)
 {
        struct dm_target_io *tio = alloc_tio(ci, ti, ci->bio->bi_max_vecs, target_bio_nr);
        struct bio *clone = &tio->clone;
@@ -1137,31 +1138,29 @@ static void __issue_target_request(struct clone_info *ci, struct dm_target *ti,
        __map_bio(tio);
 }
 
-static void __issue_target_bios(struct clone_info *ci, struct dm_target *ti,
-                               unsigned num_bios, sector_t len)
+static void __send_duplicate_bios(struct clone_info *ci, struct dm_target *ti,
+                                 unsigned num_bios, sector_t len)
 {
        unsigned target_bio_nr;
 
        for (target_bio_nr = 0; target_bio_nr < num_bios; target_bio_nr++)
-               __issue_target_request(ci, ti, target_bio_nr, len);
+               __clone_and_map_simple_bio(ci, ti, target_bio_nr, len);
 }
 
-static int __clone_and_map_empty_flush(struct clone_info *ci)
+static int __send_empty_flush(struct clone_info *ci)
 {
        unsigned target_nr = 0;
        struct dm_target *ti;
 
        BUG_ON(bio_has_data(ci->bio));
        while ((ti = dm_table_get_target(ci->map, target_nr++)))
-               __issue_target_bios(ci, ti, ti->num_flush_bios, 0);
+               __send_duplicate_bios(ci, ti, ti->num_flush_bios, 0);
 
        return 0;
 }
 
-/*
- * Perform all io with a single clone.
- */
-static void __clone_and_map_simple(struct clone_info *ci, struct dm_target *ti)
+static void __clone_and_map_data_bio(struct clone_info *ci,
+                                    struct dm_target *ti)
 {
        struct bio *bio = ci->bio;
        struct dm_target_io *tio;
@@ -1192,9 +1191,9 @@ static bool is_split_required_for_discard(struct dm_target *ti)
        return ti->split_discard_bios;
 }
 
-static int __clone_and_map_changing_extent_only(struct clone_info *ci,
-                                               get_num_bios_fn get_num_bios,
-                                               is_split_required_fn is_split_required)
+static int __send_changing_extent_only(struct clone_info *ci,
+                                      get_num_bios_fn get_num_bios,
+                                      is_split_required_fn is_split_required)
 {
        struct dm_target *ti;
        sector_t len;
@@ -1220,7 +1219,7 @@ static int __clone_and_map_changing_extent_only(struct clone_info *ci,
                else
                        len = min(ci->sector_count, max_io_len(ci->sector, ti));
 
-               __issue_target_bios(ci, ti, num_bios, len);
+               __send_duplicate_bios(ci, ti, num_bios, len);
 
                ci->sector += len;
        } while (ci->sector_count -= len);
@@ -1228,18 +1227,18 @@ static int __clone_and_map_changing_extent_only(struct clone_info *ci,
        return 0;
 }
 
-static int __clone_and_map_discard(struct clone_info *ci)
+static int __send_discard(struct clone_info *ci)
 {
-       return __clone_and_map_changing_extent_only(ci, get_num_discard_bios,
-                                                   is_split_required_for_discard);
+       return __send_changing_extent_only(ci, get_num_discard_bios,
+                                          is_split_required_for_discard);
 }
 
-static int __clone_and_map_write_same(struct clone_info *ci)
+static int __send_write_same(struct clone_info *ci)
 {
-       return __clone_and_map_changing_extent_only(ci, get_num_write_same_bios, NULL);
+       return __send_changing_extent_only(ci, get_num_write_same_bios, NULL);
 }
 
-static int __clone_and_map(struct clone_info *ci)
+static int __split_and_process_non_flush(struct clone_info *ci)
 {
        struct bio *bio = ci->bio;
        struct dm_target *ti;
@@ -1247,9 +1246,9 @@ static int __clone_and_map(struct clone_info *ci)
        struct dm_target_io *tio;
 
        if (unlikely(bio->bi_rw & REQ_DISCARD))
-               return __clone_and_map_discard(ci);
+               return __send_discard(ci);
        else if (unlikely(bio->bi_rw & REQ_WRITE_SAME))
-               return __clone_and_map_write_same(ci);
+               return __send_write_same(ci);
 
        ti = dm_table_find_target(ci->map, ci->sector);
        if (!dm_target_is_valid(ti))
@@ -1262,7 +1261,7 @@ static int __clone_and_map(struct clone_info *ci)
                 * Optimise for the simple case where we can do all of
                 * the remaining io with a single clone.
                 */
-               __clone_and_map_simple(ci, ti);
+               __clone_and_map_data_bio(ci, ti);
 
        } else if (to_sector(bio->bi_io_vec[ci->idx].bv_len) <= max) {
                /*
@@ -1311,8 +1310,8 @@ static int __clone_and_map(struct clone_info *ci)
                        len = min(remaining, max);
 
                        tio = alloc_tio(ci, ti, 1, 0);
-                       split_bvec(tio, bio, ci->sector, ci->idx,
-                                  bv->bv_offset + offset, len);
+                       clone_split_bio(tio, bio, ci->sector, ci->idx,
+                                       bv->bv_offset + offset, len);
 
                        __map_bio(tio);
 
@@ -1328,7 +1327,7 @@ static int __clone_and_map(struct clone_info *ci)
 }
 
 /*
- * Split the bio into several clones and submit it to targets.
+ * Entry point to split a bio into clones and submit them to the targets.
  */
 static void __split_and_process_bio(struct mapped_device *md, struct bio *bio)
 {
@@ -1356,13 +1355,13 @@ static void __split_and_process_bio(struct mapped_device *md, struct bio *bio)
        if (bio->bi_rw & REQ_FLUSH) {
                ci.bio = &ci.md->flush_bio;
                ci.sector_count = 0;
-               error = __clone_and_map_empty_flush(&ci);
+               error = __send_empty_flush(&ci);
                /* dec_pending submits any data associated with flush */
        } else {
                ci.bio = bio;
                ci.sector_count = bio_sectors(bio);
                while (ci.sector_count && !error)
-                       error = __clone_and_map(&ci);
+                       error = __split_and_process_non_flush(&ci);
        }
 
        /* drop the extra reference count */