[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>

8 files changed, 26 insertions, 54 deletions

diff --git a/drivers/md/linear.c b/drivers/md/linear.c
index bb279fa..946efef 100644
--- a/drivers/md/linear.c
+++ b/drivers/md/linear.c
@@ -271,6 +271,7 @@ static int linear_stop (mddev_t *mddev)
 
 static int linear_make_request (request_queue_t *q, struct bio *bio)
 {
+	const int rw = bio_data_dir(bio);
 	mddev_t *mddev = q->queuedata;
 	dev_info_t *tmp_dev;
 	sector_t block;
@@ -280,13 +281,8 @@ static int linear_make_request (request_queue_t *q, struct bio *bio)
 		return 0;
 	}
 
-	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));
 
 	tmp_dev = which_dev(mddev, bio->bi_sector);
 	block = bio->bi_sector >> 1;
diff --git a/drivers/md/md.c b/drivers/md/md.c
index 2a8a569..9ecf51e 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -3466,8 +3466,8 @@ static int is_mddev_idle(mddev_t *mddev)
 	idle = 1;
 	ITERATE_RDEV(mddev,rdev,tmp) {
 		struct gendisk *disk = rdev->bdev->bd_contains->bd_disk;
-		curr_events = disk_stat_read(disk, read_sectors) + 
-				disk_stat_read(disk, write_sectors) - 
+		curr_events = disk_stat_read(disk, sectors[0]) + 
+				disk_stat_read(disk, sectors[1]) - 
 				atomic_read(&disk->sync_io);
 		/* Allow some slack between valud of curr_events and last_events,
 		 * as there are some uninteresting races.
diff --git a/drivers/md/multipath.c b/drivers/md/multipath.c
index 1151c3e..c06f447 100644
--- a/drivers/md/multipath.c
+++ b/drivers/md/multipath.c
@@ -168,6 +168,7 @@ static int multipath_make_request (request_queue_t *q, struct bio * bio)
 	multipath_conf_t *conf = mddev_to_conf(mddev);
 	struct multipath_bh * mp_bh;
 	struct multipath_info *multipath;
+	const int rw = bio_data_dir(bio);
 
 	if (unlikely(bio_barrier(bio))) {
 		bio_endio(bio, bio->bi_size, -EOPNOTSUPP);
@@ -179,13 +180,8 @@ static int multipath_make_request (request_queue_t *q, struct bio * bio)
 	mp_bh->master_bio = bio;
 	mp_bh->mddev = mddev;
 
-	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));
 
 	mp_bh->path = multipath_map(conf);
 	if (mp_bh->path < 0) {
diff --git a/drivers/md/raid0.c b/drivers/md/raid0.c
index f675725..fece327 100644
--- a/drivers/md/raid0.c
+++ b/drivers/md/raid0.c
@@ -403,19 +403,15 @@ static int raid0_make_request (request_queue_t *q, struct bio *bio)
 	mdk_rdev_t *tmp_dev;
 	unsigned long chunk;
 	sector_t block, rsect;
+	const int rw = bio_data_dir(bio);
 
 	if (unlikely(bio_barrier(bio))) {
 		bio_endio(bio, bio->bi_size, -EOPNOTSUPP);
 		return 0;
 	}
 
-	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));
 
 	chunk_size = mddev->chunk_size >> 10;
 	chunk_sects = mddev->chunk_size >> 9;
diff --git a/drivers/md/raid1.c b/drivers/md/raid1.c
index 0e1f148..e16f473 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:
 		 */
diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c
index 28dd028..bbe40e9 100644
--- a/drivers/md/raid10.c
+++ b/drivers/md/raid10.c
@@ -668,6 +668,7 @@ static int make_request(request_queue_t *q, struct bio * bio)
 	struct bio *read_bio;
 	int i;
 	int chunk_sects = conf->chunk_mask + 1;
+	const int rw = bio_data_dir(bio);
 
 	if (unlikely(bio_barrier(bio))) {
 		bio_endio(bio, bio->bi_size, -EOPNOTSUPP);
@@ -718,13 +719,8 @@ 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));
 
 	r10_bio = mempool_alloc(conf->r10bio_pool, GFP_NOIO);
 
@@ -734,7 +730,7 @@ static int make_request(request_queue_t *q, struct bio * bio)
 	r10_bio->mddev = mddev;
 	r10_bio->sector = bio->bi_sector;
 
-	if (bio_data_dir(bio) == READ) {
+	if (rw == READ) {
 		/*
 		 * read balancing logic:
 		 */
diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index 4683ca2..6497295 100644
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -1462,6 +1462,7 @@ 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);
@@ -1470,13 +1471,8 @@ 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);
diff --git a/drivers/md/raid6main.c b/drivers/md/raid6main.c
index 267eb14..6437a95 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);