[BLOCK] Unify the seperate read/write io stat fields into arrays

Instead of having ->read_sectors and ->write_sectors, combine the two
into ->sectors[2] and similar for the other fields. This saves a branch
several places in the io path, since we don't have to care for what the
actual io direction is. On my x86-64 box, that's 200 bytes less text in
just the core (not counting the various drivers).

Signed-off-by: Jens Axboe <axboe@suse.de>

1 files changed, 4 insertions, 8 deletions

diff --git a/drivers/md/raid6main.c b/drivers/md/raid6main.c
index 267eb1430c83..6437a95ffc1c 100644
--- a/drivers/md/raid6main.c
+++ b/drivers/md/raid6main.c
@@ -1621,6 +1621,7 @@ static int make_request (request_queue_t *q, struct bio * bi)
         sector_t new_sector;
         sector_t logical_sector, last_sector;
         struct stripe_head *sh;
+        const int rw = bio_data_dir(bi);
 
         if (unlikely(bio_barrier(bi))) {
                 bio_endio(bi, bi->bi_size, -EOPNOTSUPP);
@@ -1629,13 +1630,8 @@ static int make_request (request_queue_t *q, struct bio * bi)
 
         md_write_start(mddev, bi);
 
-        if (bio_data_dir(bi)==WRITE) {
-                disk_stat_inc(mddev->gendisk, writes);
-                disk_stat_add(mddev->gendisk, write_sectors, bio_sectors(bi));
-        } else {
-                disk_stat_inc(mddev->gendisk, reads);
-                disk_stat_add(mddev->gendisk, read_sectors, bio_sectors(bi));
-        }
+        disk_stat_inc(mddev->gendisk, ios[rw]);
+        disk_stat_add(mddev->gendisk, sectors[rw], bio_sectors(bi));
 
         logical_sector = bi->bi_sector & ~((sector_t)STRIPE_SECTORS-1);
         last_sector = bi->bi_sector + (bi->bi_size>>9);
@@ -1682,7 +1678,7 @@ static int make_request (request_queue_t *q, struct bio * bi)
         if (--bi->bi_phys_segments == 0) {
                 int bytes = bi->bi_size;
 
-                if ( bio_data_dir(bi) == WRITE )
+                if (rw == WRITE )
                         md_write_end(mddev);
                 bi->bi_size = 0;
                 bi->bi_end_io(bi, bytes, 0);