[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>

12 files changed, 61 insertions, 105 deletions

diff --git a/drivers/block/genhd.c b/drivers/block/genhd.c
index 486ce1fdeb8c..54aec4a1ae13 100644
--- a/drivers/block/genhd.c
+++ b/drivers/block/genhd.c
@@ -391,13 +391,12 @@ static ssize_t disk_stats_read(struct gendisk * disk, char *page)
                 "%8u %8u %8llu %8u "
                 "%8u %8u %8u"
                 "\n",
-                disk_stat_read(disk, reads), disk_stat_read(disk, read_merges),
-                (unsigned long long)disk_stat_read(disk, read_sectors),
-                jiffies_to_msecs(disk_stat_read(disk, read_ticks)),
-                disk_stat_read(disk, writes), 
-                disk_stat_read(disk, write_merges),
-                (unsigned long long)disk_stat_read(disk, write_sectors),
-                jiffies_to_msecs(disk_stat_read(disk, write_ticks)),
+                disk_stat_read(disk, ios[0]), disk_stat_read(disk, merges[0]),
+                (unsigned long long)disk_stat_read(disk, sectors[0]),
+                jiffies_to_msecs(disk_stat_read(disk, ticks[0])),
+                disk_stat_read(disk, ios[1]), disk_stat_read(disk, merges[1]),
+                (unsigned long long)disk_stat_read(disk, sectors[1]),
+                jiffies_to_msecs(disk_stat_read(disk, ticks[1])),
                 disk->in_flight,
                 jiffies_to_msecs(disk_stat_read(disk, io_ticks)),
                 jiffies_to_msecs(disk_stat_read(disk, time_in_queue)));
@@ -583,12 +582,12 @@ static int diskstats_show(struct seq_file *s, void *v)
         preempt_enable();
         seq_printf(s, "%4d %4d %s %u %u %llu %u %u %u %llu %u %u %u %u\n",
                 gp->major, n + gp->first_minor, disk_name(gp, n, buf),
-                disk_stat_read(gp, reads), disk_stat_read(gp, read_merges),
-                (unsigned long long)disk_stat_read(gp, read_sectors),
-                jiffies_to_msecs(disk_stat_read(gp, read_ticks)),
-                disk_stat_read(gp, writes), disk_stat_read(gp, write_merges),
-                (unsigned long long)disk_stat_read(gp, write_sectors),
-                jiffies_to_msecs(disk_stat_read(gp, write_ticks)),
+                disk_stat_read(gp, ios[0]), disk_stat_read(gp, merges[0]),
+                (unsigned long long)disk_stat_read(gp, sectors[0]),
+                jiffies_to_msecs(disk_stat_read(gp, ticks[0])),
+                disk_stat_read(gp, ios[1]), disk_stat_read(gp, merges[1]),
+                (unsigned long long)disk_stat_read(gp, sectors[1]),
+                jiffies_to_msecs(disk_stat_read(gp, ticks[1])),
                 gp->in_flight,
                 jiffies_to_msecs(disk_stat_read(gp, io_ticks)),
                 jiffies_to_msecs(disk_stat_read(gp, time_in_queue)));
@@ -601,8 +600,8 @@ static int diskstats_show(struct seq_file *s, void *v)
                         seq_printf(s, "%4d %4d %s %u %u %u %u\n",
                                 gp->major, n + gp->first_minor + 1,
                                 disk_name(gp, n + 1, buf),
-                                hd->reads, hd->read_sectors,
-                                hd->writes, hd->write_sectors);
+                                hd->ios[0], hd->sectors[0],
+                                hd->ios[1], hd->sectors[1]);
         }
  
         return 0;
diff --git a/drivers/block/ll_rw_blk.c b/drivers/block/ll_rw_blk.c
index 1b272883aadf..2747741677fb 100644
--- a/drivers/block/ll_rw_blk.c
+++ b/drivers/block/ll_rw_blk.c
@@ -2388,10 +2388,7 @@ static void drive_stat_acct(struct request *rq, int nr_sectors, int new_io)
                 return;
 
         if (!new_io) {
-                if (rw == READ)
-                        __disk_stat_inc(rq->rq_disk, read_merges);
-                else
-                        __disk_stat_inc(rq->rq_disk, write_merges);
+                __disk_stat_inc(rq->rq_disk, merges[rw]);
         } else {
                 disk_round_stats(rq->rq_disk);
                 rq->rq_disk->in_flight++;
@@ -2787,17 +2784,11 @@ static inline void blk_partition_remap(struct bio *bio)
 
         if (bdev != bdev->bd_contains) {
                 struct hd_struct *p = bdev->bd_part;
+                const int rw = bio_data_dir(bio);
+
+                p->sectors[rw] += bio_sectors(bio);
+                p->ios[rw]++;
 
-                switch (bio_data_dir(bio)) {
-                case READ:
-                        p->read_sectors += bio_sectors(bio);
-                        p->reads++;
-                        break;
-                case WRITE:
-                        p->write_sectors += bio_sectors(bio);
-                        p->writes++;
-                        break;
-                }
                 bio->bi_sector += p->start_sect;
                 bio->bi_bdev = bdev->bd_contains;
         }
@@ -3045,10 +3036,9 @@ static int __end_that_request_first(struct request *req, int uptodate,
         }
 
         if (blk_fs_request(req) && req->rq_disk) {
-                if (rq_data_dir(req) == READ)
-                        __disk_stat_add(req->rq_disk, read_sectors, nr_bytes >> 9);
-                else
-                        __disk_stat_add(req->rq_disk, write_sectors, nr_bytes >> 9);
+                const int rw = rq_data_dir(req);
+
+                __disk_stat_add(req->rq_disk, sectors[rw], nr_bytes >> 9);
         }
 
         total_bytes = bio_nbytes = 0;
@@ -3179,16 +3169,10 @@ void end_that_request_last(struct request *req)
 
         if (disk && blk_fs_request(req)) {
                 unsigned long duration = jiffies - req->start_time;
-                switch (rq_data_dir(req)) {
-                    case WRITE:
-                        __disk_stat_inc(disk, writes);
-                        __disk_stat_add(disk, write_ticks, duration);
-                        break;
-                    case READ:
-                        __disk_stat_inc(disk, reads);
-                        __disk_stat_add(disk, read_ticks, duration);
-                        break;
-                }
+                const int rw = rq_data_dir(req);
+
+                __disk_stat_inc(disk, ios[rw]);
+                __disk_stat_add(disk, ticks[rw], duration);
                 disk_round_stats(disk);
                 disk->in_flight--;
         }
diff --git a/drivers/md/linear.c b/drivers/md/linear.c
index bb279fad2fd2..946efef3a8f5 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 2a8a5696bf8a..9ecf51ee596f 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 1151c3ed3006..c06f4474192b 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 f6757259ce7f..fece3277c2a5 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 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:
                  */
diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c
index 28dd028415e4..bbe40e9cf923 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 4683ca24c046..6497295ebfb9 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 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);
diff --git a/fs/partitions/check.c b/fs/partitions/check.c
index 9c06c5434ec4..8dc1822a7022 100644
--- a/fs/partitions/check.c
+++ b/fs/partitions/check.c
@@ -246,8 +246,8 @@ static ssize_t part_size_read(struct hd_struct * p, char *page)
 static ssize_t part_stat_read(struct hd_struct * p, char *page)
 {
         return sprintf(page, "%8u %8llu %8u %8llu\n",
-                       p->reads, (unsigned long long)p->read_sectors,
-                       p->writes, (unsigned long long)p->write_sectors);
+                       p->ios[0], (unsigned long long)p->sectors[0],
+                       p->ios[1], (unsigned long long)p->sectors[1]);
 }
 static struct part_attribute part_attr_uevent = {
         .attr = {.name = "uevent", .mode = S_IWUSR },
@@ -303,7 +303,8 @@ void delete_partition(struct gendisk *disk, int part)
         disk->part[part-1] = NULL;
         p->start_sect = 0;
         p->nr_sects = 0;
-        p->reads = p->writes = p->read_sectors = p->write_sectors = 0;
+        p->ios[0] = p->ios[1] = 0;
+        p->sectors[0] = p->sectors[1] = 0;
         devfs_remove("%s/part%d", disk->devfs_name, part);
         kobject_unregister(&p->kobj);
 }
diff --git a/include/linux/genhd.h b/include/linux/genhd.h
index eabdb5cce357..8eeaa53a68c9 100644
--- a/include/linux/genhd.h
+++ b/include/linux/genhd.h
@@ -78,7 +78,7 @@ struct hd_struct {
         sector_t start_sect;
         sector_t nr_sects;
         struct kobject kobj;
-        unsigned reads, read_sectors, writes, write_sectors;
+        unsigned ios[2], sectors[2];
         int policy, partno;
 };
 
@@ -89,10 +89,10 @@ struct hd_struct {
 #define GENHD_FL_SUPPRESS_PARTITION_INFO        32
 
 struct disk_stats {
-        unsigned read_sectors, write_sectors;
-        unsigned reads, writes;
-        unsigned read_merges, write_merges;
-        unsigned read_ticks, write_ticks;
+        unsigned sectors[2];
+        unsigned ios[2];
+        unsigned merges[2];
+        unsigned ticks[2];
         unsigned io_ticks;
         unsigned time_in_queue;
 };