dm: support non power of two target max_io_len

Remove the restriction that limits a target's specified maximum incoming
I/O size to be a power of 2.

Rename this setting from 'split_io' to the less-ambiguous 'max_io_len'.
Change it from sector_t to uint32_t, which is plenty big enough, and
introduce a wrapper function dm_set_target_max_io_len() to set it.
Use sector_div() to process it now that it is not necessarily a power of 2.

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

1 files changed, 5 insertions, 6 deletions

diff --git a/drivers/md/dm-raid.c b/drivers/md/dm-raid.c
index 017c34d78d61..858a8b70811c 100644
--- a/drivers/md/dm-raid.c
+++ b/drivers/md/dm-raid.c
@@ -353,6 +353,7 @@ static int parse_raid_params(struct raid_set *rs, char **argv,
 {
         unsigned i, rebuild_cnt = 0;
         unsigned long value, region_size = 0;
+        sector_t max_io_len;
         char *key;
 
         /*
@@ -522,14 +523,12 @@ static int parse_raid_params(struct raid_set *rs, char **argv,
                 return -EINVAL;
 
         if (rs->md.chunk_sectors)
-                rs->ti->split_io = rs->md.chunk_sectors;
+                max_io_len = rs->md.chunk_sectors;
         else
-                rs->ti->split_io = region_size;
+                max_io_len = region_size;
 
-        if (rs->md.chunk_sectors)
-                rs->ti->split_io = rs->md.chunk_sectors;
-        else
-                rs->ti->split_io = region_size;
+        if (dm_set_target_max_io_len(rs->ti, max_io_len))
+                return -EINVAL;
 
         /* Assume there are no metadata devices until the drives are parsed */
         rs->md.persistent = 0;