[PATCH 31/45] block: move disk stat accounting to struct block_device

Christoph Hellwig
2020-11-28T22:10:31Z

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>
---
block/blk-cgroup.c | 2 +-
block/blk-core.c | 4 ++--
block/blk.h | 1 -
block/genhd.c | 14 ++++----------
block/partitions/core.c | 9 +--------
fs/block_dev.c | 10 ++++++++++
include/linux/blk_types.h | 2 ++
include/linux/genhd.h | 2 --
include/linux/part_stat.h | 38 +++++++++++++++++++-------------------
9 files changed, 39 insertions(+), 43 deletions(-)

diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c
index 19650eb42b9f00..5c0a9d588e6312 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 988f45094a387b..d2c9cb24e087f3 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 09cee7024fb43e..3f801f6e86f8a1 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 c6016fde4725b0..9eead2970cb3d4 100644
--- a/block/genhd.c
+++ b/block/genhd.c
@@ -104,7 +104,7 @@ 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++) {
@@ -883,7 +883,7 @@ 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);
@@ -1620,19 +1620,15 @@ 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);
@@ -1641,8 +1637,6 @@ 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 bcfa8215bd5ef3..8924e1ea8b2ad6 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 @@ static struct hd_struct *add_partition(struct gendisk *disk, int partno,
kfree(p->info);
out_bdput:
bdput(bdev);
-out_free_stats:
- free_percpu(p->dkstats);
out_free:
kfree(p);
return ERR_PTR(err);
diff --git a/fs/block_dev.c b/fs/block_dev.c
index 31ee5a857f7153..0832c7830f3a10 100644
--- a/fs/block_dev.c
+++ b/fs/block_dev.c
@@ -32,6 +32,7 @@
#include <linux/cleancache.h>
#include <linux/task_io_accounting_ops.h>
#include <linux/falloc.h>
+#include <linux/part_stat.h>
#include <linux/uaccess.h>
#include <linux/suspend.h>
#include "internal.h"
@@ -781,6 +782,10 @@ static struct inode *bdev_alloc_inode(struct super_block *sb)

static void bdev_free_inode(struct inode *inode)
{
+ struct block_device *bdev = I_BDEV(inode);
+
+ free_percpu(bdev->bd_stats);
+
kmem_cache_free(bdev_cachep, BDEV_I(inode));
}

@@ -875,6 +880,11 @@ struct block_device *bdev_alloc(struct gendisk *disk, u8 partno)
#ifdef CONFIG_SYSFS
INIT_LIST_HEAD(&bdev->bd_holder_disks);
#endif
+ bdev->bd_stats = alloc_percpu(struct disk_stats);
+ if (!bdev->bd_stats) {
+ iput(inode);
+ return NULL;
+ }
return bdev;
}

diff --git a/include/linux/blk_types.h b/include/linux/blk_types.h
index 2e0a9bd9688d28..520011b95276fb 100644
--- a/include/linux/blk_types.h
+++ b/include/linux/blk_types.h
@@ -20,6 +20,8 @@ typedef void (bio_end_io_t) (struct bio *);
struct bio_crypt_ctx;

struct block_device {
+ struct disk_stats __percpu *bd_stats;
+ unsigned long bd_stamp;
dev_t bd_dev;
int bd_openers;
struct inode * bd_inode; /* will die */
diff --git a/include/linux/genhd.h b/include/linux/genhd.h
index 30d4785b7df8bb..804ac45fbfbc53 100644
--- a/include/linux/genhd.h
+++ b/include/linux/genhd.h
@@ -52,8 +52,6 @@ struct partition_meta_info {

struct hd_struct {
sector_t start_sect;
- unsigned long stamp;
- struct disk_stats __percpu *dkstats;
struct percpu_ref ref;

struct block_device *bdev;
diff --git a/include/linux/part_stat.h b/include/linux/part_stat.h
index 24125778ef3ec7..87ad60106e1db0 100644
--- a/include/linux/part_stat.h
+++ b/include/linux/part_stat.h
@@ -25,17 +25,17 @@ struct disk_stats {
#define part_stat_unlock() preempt_enable()

#define part_stat_get_cpu(part, field, cpu) \
- (per_cpu_ptr((part)->dkstats, (cpu))->field)
+ (per_cpu_ptr((part)->bdev->bd_stats, (cpu))->field)

#define part_stat_get(part, field) \
part_stat_get_cpu(part, field, smp_processor_id())

#define part_stat_read(part, field) \
({ \
- typeof((part)->dkstats->field) res = 0; \
+ typeof((part)->bdev->bd_stats->field) res = 0; \
unsigned int _cpu; \
for_each_possible_cpu(_cpu) \
- res += per_cpu_ptr((part)->dkstats, _cpu)->field; \
+ res += per_cpu_ptr((part)->bdev->bd_stats, _cpu)->field; \
res; \
})

@@ -44,7 +44,7 @@ static inline void part_stat_set_all(struct hd_struct *part, int value)
int i;

for_each_possible_cpu(i)
- memset(per_cpu_ptr(part->dkstats, i), value,
+ memset(per_cpu_ptr(part->bdev->bd_stats, i), value,
sizeof(struct disk_stats));
}

@@ -54,7 +54,7 @@ static inline void part_stat_set_all(struct hd_struct *part, int value)
part_stat_read(part, field[STAT_DISCARD]))

#define __part_stat_add(part, field, addnd) \
- __this_cpu_add((part)->dkstats->field, addnd)
+ __this_cpu_add((part)->bdev->bd_stats->field, addnd)

#define part_stat_add(part, field, addnd) do { \
__part_stat_add((part), field, addnd); \
@@ -63,20 +63,20 @@ static inline void part_stat_set_all(struct hd_struct *part, int value)
field, addnd); \
} while (0)

-#define part_stat_dec(gendiskp, field) \
- part_stat_add(gendiskp, field, -1)
-#define part_stat_inc(gendiskp, field) \
- part_stat_add(gendiskp, field, 1)
-#define part_stat_sub(gendiskp, field, subnd) \
- part_stat_add(gendiskp, field, -subnd)
+#define part_stat_dec(part, field) \
+ part_stat_add(part, field, -1)
+#define part_stat_inc(part, field) \
+ part_stat_add(part, field, 1)
+#define part_stat_sub(part, field, subnd) \
+ part_stat_add(part, field, -subnd)

-#define part_stat_local_dec(gendiskp, field) \
- local_dec(&(part_stat_get(gendiskp, field)))
-#define part_stat_local_inc(gendiskp, field) \
- local_inc(&(part_stat_get(gendiskp, field)))
-#define part_stat_local_read(gendiskp, field) \
- local_read(&(part_stat_get(gendiskp, field)))
-#define part_stat_local_read_cpu(gendiskp, field, cpu) \
- local_read(&(part_stat_get_cpu(gendiskp, field, cpu)))
+#define part_stat_local_dec(part, field) \
+ local_dec(&(part_stat_get(part, field)))
+#define part_stat_local_inc(part, field) \
+ local_inc(&(part_stat_get(part, field)))
+#define part_stat_local_read(part, field) \
+ local_read(&(part_stat_get(part, field)))
+#define part_stat_local_read_cpu(part, field, cpu) \
+ local_read(&(part_stat_get_cpu(part, field, cpu)))

#endif /* _LINUX_PART_STAT_H */
--
2.29.2