[dm-devel] [PATCH 3/8] block: look up holders by bdev
Christoph Hellwig
hch at lst.de
Sun Jul 25 05:54:53 UTC 2021
Invert they way the holder relations are tracked. This very
slightly reduces the memory overhead for partitioned devices.
Signed-off-by: Christoph Hellwig <hch at lst.de>
---
block/genhd.c | 3 +++
block/holder.c | 18 +++++++++---------
fs/block_dev.c | 3 ---
include/linux/blk_types.h | 3 ---
include/linux/genhd.h | 4 +++-
5 files changed, 15 insertions(+), 16 deletions(-)
diff --git a/block/genhd.c b/block/genhd.c
index af4d2ab4a633..e2708a4a7a47 100644
--- a/block/genhd.c
+++ b/block/genhd.c
@@ -1263,6 +1263,9 @@ 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_BLOCK_HOLDER_DEPRECATED
+ INIT_LIST_HEAD(&disk->slave_bdevs);
+#endif
return disk;
out_destroy_part_tbl:
diff --git a/block/holder.c b/block/holder.c
index 960654a71342..11e65d99a9fb 100644
--- a/block/holder.c
+++ b/block/holder.c
@@ -3,7 +3,7 @@
struct bd_holder_disk {
struct list_head list;
- struct gendisk *disk;
+ struct block_device *bdev;
int refcnt;
};
@@ -12,8 +12,8 @@ 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;
}
@@ -61,7 +61,7 @@ int bd_link_disk_holder(struct block_device *bdev, struct gendisk *disk)
struct bd_holder_disk *holder;
int ret = 0;
- mutex_lock(&bdev->bd_disk->open_mutex);
+ mutex_lock(&disk->open_mutex);
WARN_ON_ONCE(!bdev->bd_holder);
@@ -82,7 +82,7 @@ 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, bdev_kobj(bdev));
@@ -93,7 +93,7 @@ int bd_link_disk_holder(struct block_device *bdev, struct gendisk *disk)
if (ret)
goto out_del;
- list_add(&holder->list, &bdev->bd_holder_disks);
+ list_add(&holder->list, &disk->slave_bdevs);
goto out_unlock;
out_del:
@@ -101,7 +101,7 @@ int bd_link_disk_holder(struct block_device *bdev, struct gendisk *disk)
out_free:
kfree(holder);
out_unlock:
- mutex_unlock(&bdev->bd_disk->open_mutex);
+ mutex_unlock(&disk->open_mutex);
return ret;
}
EXPORT_SYMBOL_GPL(bd_link_disk_holder);
@@ -120,7 +120,7 @@ void bd_unlink_disk_holder(struct block_device *bdev, struct gendisk *disk)
{
struct bd_holder_disk *holder;
- mutex_lock(&bdev->bd_disk->open_mutex);
+ mutex_lock(&disk->open_mutex);
holder = bd_find_holder_disk(bdev, disk);
if (!WARN_ON_ONCE(holder == NULL) && !--holder->refcnt) {
del_symlink(disk->slave_dir, bdev_kobj(bdev));
@@ -128,6 +128,6 @@ void bd_unlink_disk_holder(struct block_device *bdev, struct gendisk *disk)
list_del_init(&holder->list);
kfree(holder);
}
- mutex_unlock(&bdev->bd_disk->open_mutex);
+ mutex_unlock(&disk->open_mutex);
}
EXPORT_SYMBOL_GPL(bd_unlink_disk_holder);
diff --git a/fs/block_dev.c b/fs/block_dev.c
index 7825d152634e..22646906ddaa 100644
--- a/fs/block_dev.c
+++ b/fs/block_dev.c
@@ -900,9 +900,6 @@ struct block_device *bdev_alloc(struct gendisk *disk, u8 partno)
bdev->bd_disk = disk;
bdev->bd_partno = partno;
bdev->bd_inode = inode;
-#ifdef CONFIG_BLOCK_HOLDER_DEPRECATED
- INIT_LIST_HEAD(&bdev->bd_holder_disks);
-#endif
bdev->bd_stats = alloc_percpu(struct disk_stats);
if (!bdev->bd_stats) {
iput(inode);
diff --git a/include/linux/blk_types.h b/include/linux/blk_types.h
index 7a4e139d24ef..e92735655684 100644
--- a/include/linux/blk_types.h
+++ b/include/linux/blk_types.h
@@ -34,9 +34,6 @@ struct block_device {
void * bd_holder;
int bd_holders;
bool bd_write_holder;
-#ifdef CONFIG_BLOCK_HOLDER_DEPRECATED
- struct list_head bd_holder_disks;
-#endif
struct kobject *bd_holder_dir;
u8 bd_partno;
spinlock_t bd_size_lock; /* for bd_inode->i_size updates */
diff --git a/include/linux/genhd.h b/include/linux/genhd.h
index 6831d74f2002..26c8557e2714 100644
--- a/include/linux/genhd.h
+++ b/include/linux/genhd.h
@@ -159,7 +159,9 @@ struct gendisk {
unsigned open_partitions; /* number of open partitions */
struct kobject *slave_dir;
-
+#ifdef CONFIG_BLOCK_HOLDER_DEPRECATED
+ struct list_head slave_bdevs;
+#endif
struct timer_rand_state *random;
atomic_t sync_io; /* RAID */
struct disk_events *ev;
--
2.30.2
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