From: Christoph Hellwig <hch@xxxxxx>
commit 0dbcfe247f22a6d73302dfa691c48b3c14d31c4c upstream.
Invert they way the holder relations are tracked. This very
slightly reduces the memory overhead for partitioned devices.
Signed-off-by: Christoph Hellwig <hch@xxxxxx>
Signed-off-by: Yu Kuai <yukuai3@xxxxxxxxxx>
---
block/genhd.c | 3 +++
fs/block_dev.c | 31 +++++++++++++++++++------------
include/linux/blk_types.h | 3 ---
include/linux/genhd.h | 4 +++-
4 files changed, 25 insertions(+), 16 deletions(-)
diff --git a/block/genhd.c b/block/genhd.c
index 796baf761202..2b11a2735285 100644
--- a/block/genhd.c
+++ b/block/genhd.c
@@ -1760,6 +1760,9 @@ struct gendisk *__alloc_disk_node(int minors, int node_id)
disk_to_dev(disk)->class = &block_class;
disk_to_dev(disk)->type = &disk_type;
device_initialize(disk_to_dev(disk));
+#ifdef CONFIG_SYSFS
+ INIT_LIST_HEAD(&disk->slave_bdevs);
+#endif
return disk;
out_free_part0:
diff --git a/fs/block_dev.c b/fs/block_dev.c
index 29f020c4b2d0..a202c76fcf7f 100644
--- a/fs/block_dev.c
+++ b/fs/block_dev.c
@@ -823,9 +823,6 @@ static void init_once(void *foo)
memset(bdev, 0, sizeof(*bdev));
mutex_init(&bdev->bd_mutex);
-#ifdef CONFIG_SYSFS
- INIT_LIST_HEAD(&bdev->bd_holder_disks);
-#endif
bdev->bd_bdi = &noop_backing_dev_info;
inode_init_once(&ei->vfs_inode);
/* Initialize mutex for freeze. */
@@ -1188,7 +1185,7 @@ EXPORT_SYMBOL(bd_abort_claiming);
#ifdef CONFIG_SYSFS
struct bd_holder_disk {
struct list_head list;
- struct gendisk *disk;
+ struct block_device *bdev;
int refcnt;
};
@@ -1197,8 +1194,8 @@ static struct bd_holder_disk *bd_find_holder_disk(struct block_device *bdev,
{
struct bd_holder_disk *holder;
- list_for_each_entry(holder, &bdev->bd_holder_disks, list)
- if (holder->disk == disk)
+ list_for_each_entry(holder, &disk->slave_bdevs, list)
+ if (holder->bdev == bdev)
return holder;
return NULL;
}
@@ -1244,9 +1241,13 @@ static void del_symlink(struct kobject *from, struct kobject *to)
int bd_link_disk_holder(struct block_device *bdev, struct gendisk *disk)
{
struct bd_holder_disk *holder;
+ struct block_device *bdev_holder = bdget_disk(disk, 0);
int ret = 0;
- mutex_lock(&bdev->bd_mutex);
+ if (WARN_ON_ONCE(!bdev_holder))
+ return -ENOENT;
+
+ mutex_lock(&bdev_holder->bd_mutex);
WARN_ON_ONCE(!bdev->bd_holder);
@@ -1267,7 +1268,7 @@ int bd_link_disk_holder(struct block_device *bdev, struct gendisk *disk)
}
INIT_LIST_HEAD(&holder->list);
- holder->disk = disk;
+ holder->bdev = bdev;
holder->refcnt = 1;
ret = add_symlink(disk->slave_dir, &part_to_dev(bdev->bd_part)->kobj);
@@ -1283,7 +1284,7 @@ int bd_link_disk_holder(struct block_device *bdev, struct gendisk *disk)
*/
kobject_get(bdev->bd_part->holder_dir);
- list_add(&holder->list, &bdev->bd_holder_disks);
+ list_add(&holder->list, &disk->slave_bdevs);
goto out_unlock;
out_del:
@@ -1291,7 +1292,8 @@ int bd_link_disk_holder(struct block_device *bdev, struct gendisk *disk)
out_free:
kfree(holder);
out_unlock:
- mutex_unlock(&bdev->bd_mutex);
+ mutex_unlock(&bdev_holder->bd_mutex);
+ bdput(bdev_holder);
return ret;
}
EXPORT_SYMBOL_GPL(bd_link_disk_holder);
@@ -1309,8 +1311,12 @@ EXPORT_SYMBOL_GPL(bd_link_disk_holder);
void bd_unlink_disk_holder(struct block_device *bdev, struct gendisk *disk)
{
struct bd_holder_disk *holder;
+ struct block_device *bdev_holder = bdget_disk(disk, 0);
- mutex_lock(&bdev->bd_mutex);
+ if (WARN_ON_ONCE(!bdev_holder))
+ return;
+
+ mutex_lock(&bdev_holder->bd_mutex);
holder = bd_find_holder_disk(bdev, disk);
@@ -1323,7 +1329,8 @@ void bd_unlink_disk_holder(struct block_device *bdev, struct gendisk *disk)
kfree(holder);
}
- mutex_unlock(&bdev->bd_mutex);
+ mutex_unlock(&bdev_holder->bd_mutex);
+ bdput(bdev_holder);
}
EXPORT_SYMBOL_GPL(bd_unlink_disk_holder);
#endif
diff --git a/include/linux/blk_types.h b/include/linux/blk_types.h
index d9b69bbde5cc..1b84ecb34c18 100644
--- a/include/linux/blk_types.h
+++ b/include/linux/blk_types.h
@@ -29,9 +29,6 @@ struct block_device {
void * bd_holder;
int bd_holders;
bool bd_write_holder;
-#ifdef CONFIG_SYSFS
- struct list_head bd_holder_disks;
-#endif
struct block_device * bd_contains;
u8 bd_partno;
struct hd_struct * bd_part;
diff --git a/include/linux/genhd.h b/include/linux/genhd.h
index 03da3f603d30..3e5049a527e6 100644
--- a/include/linux/genhd.h
+++ b/include/linux/genhd.h
@@ -195,7 +195,9 @@ struct gendisk {
#define GD_NEED_PART_SCAN 0
struct rw_semaphore lookup_sem;
struct kobject *slave_dir;
-
+#ifdef CONFIG_SYSFS
+ struct list_head slave_bdevs;
+#endif
struct timer_rand_state *random;
atomic_t sync_io; /* RAID */
struct disk_events *ev;
--
2.31.1
