block: move stats from disk to part0

Move stats related fields - stamp, in_flight, dkstats - from disk to
part0 and unify stat handling such that...

* part_stat_*() now updates part0 together if the specified partition
  is not part0.  ie. part_stat_*() are now essentially all_stat_*().

* {disk|all}_stat_*() are gone.

* part_round_stats() is updated similary.  It handles part0 stats
  automatically and disk_round_stats() is killed.

* part_{inc|dec}_in_fligh() is implemented which automatically updates
  part0 stats for parts other than part0.

* disk_map_sector_rcu() is updated to return part0 if no part matches.
  Combined with the above changes, this makes NULL special case
  handling in callers unnecessary.

* Separate stats show code paths for disk are collapsed into part
  stats show code paths.

* Rename disk_stat_lock/unlock() to part_stat_lock/unlock()

While at it, reposition stat handling macros a bit and add missing
parentheses around macro parameters.

Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

1 files changed, 2 insertions, 2 deletions

diff --git a/drivers/md/md.c b/drivers/md/md.c
index 2bd9cf416123..0a3a4bdcd4af 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -5546,8 +5546,8 @@ static int is_mddev_idle(mddev_t *mddev)
         rcu_read_lock();
         rdev_for_each_rcu(rdev, mddev) {
                 struct gendisk *disk = rdev->bdev->bd_contains->bd_disk;
-                curr_events = disk_stat_read(disk, sectors[0]) + 
-                                disk_stat_read(disk, sectors[1]) - 
+                curr_events = part_stat_read(&disk->part0, sectors[0]) +
+                                part_stat_read(&disk->part0, sectors[1]) -
                                 atomic_read(&disk->sync_io);
                 /* sync IO will cause sync_io to increase before the disk_stats
                  * as sync_io is counted when a request starts, and