block: move disk stat accounting to struct block_device

Move the dkstats and stamp field to struct block_device in preparation
of killing struct hd_struct.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

5 files changed, 8 insertions, 22 deletions

diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c
index ad02289a4f7f..79aa96240cec 100644
--- a/block/blk-cgroup.c
+++ b/block/blk-cgroup.c
@@ -830,7 +830,7 @@ static void blkcg_fill_root_iostats(void)
 		for_each_possible_cpu(cpu) {
 			struct disk_stats *cpu_dkstats;
 
-			cpu_dkstats = per_cpu_ptr(part->dkstats, cpu);
+			cpu_dkstats = per_cpu_ptr(part->bdev->bd_stats, cpu);
 			tmp.ios[BLKG_IOSTAT_READ] +=
 				cpu_dkstats->ios[STAT_READ];
 			tmp.ios[BLKG_IOSTAT_WRITE] +=
diff --git a/block/blk-core.c b/block/blk-core.c
index 988f45094a38..d2c9cb24e087 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -1264,9 +1264,9 @@ static void update_io_ticks(struct hd_struct *part, unsigned long now, bool end)
 {
 	unsigned long stamp;
 again:
-	stamp = READ_ONCE(part->stamp);
+	stamp = READ_ONCE(part->bdev->bd_stamp);
 	if (unlikely(stamp != now)) {
-		if (likely(cmpxchg(&part->stamp, stamp, now) == stamp))
+		if (likely(cmpxchg(&part->bdev->bd_stamp, stamp, now) == stamp))
 			__part_stat_add(part, io_ticks, end ? now - stamp : 1);
 	}
 	if (part->partno) {
diff --git a/block/blk.h b/block/blk.h
index 09cee7024fb4..3f801f6e86f8 100644
--- a/block/blk.h
+++ b/block/blk.h
@@ -381,7 +381,6 @@ static inline void hd_struct_put(struct hd_struct *part)
 
 static inline void hd_free_part(struct hd_struct *part)
 {
-	free_percpu(part->dkstats);
 	kfree(part->info);
 	bdput(part->bdev);
 	percpu_ref_exit(&part->ref);
diff --git a/block/genhd.c b/block/genhd.c
index c65f485b9db5..2cbda8139556 100644
--- a/block/genhd.c
+++ b/block/genhd.c
@@ -112,7 +112,7 @@ static void part_stat_read_all(struct hd_struct *part, struct disk_stats *stat)
 
 	memset(stat, 0, sizeof(struct disk_stats));
 	for_each_possible_cpu(cpu) {
-		struct disk_stats *ptr = per_cpu_ptr(part->dkstats, cpu);
+		struct disk_stats *ptr = per_cpu_ptr(part->bdev->bd_stats, cpu);
 		int group;
 
 		for (group = 0; group < NR_STAT_GROUPS; group++) {
@@ -891,7 +891,7 @@ void del_gendisk(struct gendisk *disk)
 	kobject_put(disk->slave_dir);
 
 	part_stat_set_all(&disk->part0, 0);
-	disk->part0.stamp = 0;
+	disk->part0.bdev->bd_stamp = 0;
 	if (!sysfs_deprecated)
 		sysfs_remove_link(block_depr, dev_name(disk_to_dev(disk)));
 	pm_runtime_set_memalloc_noio(disk_to_dev(disk), false);
@@ -1628,19 +1628,15 @@ struct gendisk *__alloc_disk_node(int minors, int node_id)
 	if (!disk->part0.bdev)
 		goto out_free_disk;
 
-	disk->part0.dkstats = alloc_percpu(struct disk_stats);
-	if (!disk->part0.dkstats)
-		goto out_bdput;
-
 	disk->node_id = node_id;
 	if (disk_expand_part_tbl(disk, 0))
-		goto out_free_bdstats;
+		goto out_bdput;
 
 	ptbl = rcu_dereference_protected(disk->part_tbl, 1);
 	rcu_assign_pointer(ptbl->part[0], &disk->part0);
 
 	if (hd_ref_init(&disk->part0))
-		goto out_free_bdstats;
+		goto out_bdput;
 
 	disk->minors = minors;
 	rand_initialize_disk(disk);
@@ -1649,8 +1645,6 @@ struct gendisk *__alloc_disk_node(int minors, int node_id)
 	device_initialize(disk_to_dev(disk));
 	return disk;
 
-out_free_bdstats:
-	free_percpu(disk->part0.dkstats);
 out_bdput:
 	bdput(disk->part0.bdev);
 out_free_disk:
diff --git a/block/partitions/core.c b/block/partitions/core.c
index bcfa8215bd5e..8924e1ea8b2a 100644
--- a/block/partitions/core.c
+++ b/block/partitions/core.c
@@ -409,14 +409,9 @@ static struct hd_struct *add_partition(struct gendisk *disk, int partno,
 	if (!p)
 		return ERR_PTR(-EBUSY);
 
-	err = -ENOMEM;
-	p->dkstats = alloc_percpu(struct disk_stats);
-	if (!p->dkstats)
-		goto out_free;
-
 	bdev = bdev_alloc(disk, partno);
 	if (!bdev)
-		goto out_free_stats;
+		goto out_free;
 	p->bdev = bdev;
 
 	pdev = part_to_dev(p);
@@ -490,8 +485,6 @@ out_free_info:
 	kfree(p->info);
 out_bdput:
 	bdput(bdev);
-out_free_stats:
-	free_percpu(p->dkstats);
 out_free:
 	kfree(p);
 	return ERR_PTR(err);