[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/raid1.c b/drivers/md/raid1.c
index 0e1f148dd41d..e16f473bcf46 100644
--- a/drivers/md/raid1.c
+++ b/drivers/md/raid1.c
@@ -647,6 +647,7 @@ static int make_request(request_queue_t *q, struct bio * bio)
         unsigned long flags;
         struct bio_list bl;
         struct page **behind_pages = NULL;
+        const int rw = bio_data_dir(bio);
 
         if (unlikely(bio_barrier(bio))) {
                 bio_endio(bio, bio->bi_size, -EOPNOTSUPP);
@@ -665,13 +666,8 @@ static int make_request(request_queue_t *q, struct bio * bio)
         conf->nr_pending++;
         spin_unlock_irq(&conf->resync_lock);
 
-        if (bio_data_dir(bio)==WRITE) {
-                disk_stat_inc(mddev->gendisk, writes);
-                disk_stat_add(mddev->gendisk, write_sectors, bio_sectors(bio));
-        } else {
-                disk_stat_inc(mddev->gendisk, reads);
-                disk_stat_add(mddev->gendisk, read_sectors, bio_sectors(bio));
-        }
+        disk_stat_inc(mddev->gendisk, ios[rw]);
+        disk_stat_add(mddev->gendisk, sectors[rw], bio_sectors(bio));
 
         /*
          * make_request() can abort the operation when READA is being
@@ -686,7 +682,7 @@ static int make_request(request_queue_t *q, struct bio * bio)
         r1_bio->mddev = mddev;
         r1_bio->sector = bio->bi_sector;
 
-        if (bio_data_dir(bio) == READ) {
+        if (rw == READ) {
                 /*
                  * read balancing logic:
                  */