Move the block holder code into a separate file as it is not in any way
related to the other block_dev.c code, and add a new selectable config
option for it so that we don't have to build it without any remapped
drivers selected.
The Kconfig symbol contains a _DEPRECATED suffix to match the comments
added in commit 49731baa41df
("block: restore multiple bd_link_disk_holder() support").
Signed-off-by: Christoph Hellwig <hch@xxxxxx>
Reviewed-by: Mike Snitzer <snitzer@xxxxxxxxxx>
---
block/Kconfig | 4 ++
block/Makefile | 1 +
block/holder.c | 139 ++++++++++++++++++++++++++++++++++++
drivers/md/Kconfig | 2 +
drivers/md/bcache/Kconfig | 1 +
fs/block_dev.c | 144 +-------------------------------------
include/linux/blk_types.h | 2 +-
include/linux/genhd.h | 4 +-
8 files changed, 151 insertions(+), 146 deletions(-)
create mode 100644 block/holder.c
diff --git a/block/Kconfig b/block/Kconfig
index 15dfb7660645..bac87d773c54 100644
--- a/block/Kconfig
+++ b/block/Kconfig
@@ -241,4 +241,8 @@ config BLK_MQ_RDMA
config BLK_PM
def_bool BLOCK && PM
+# do not use in new code
+config BLOCK_HOLDER_DEPRECATED
+ bool
+
source "block/Kconfig.iosched"
diff --git a/block/Makefile b/block/Makefile
index c72592b4cf31..0d951adce796 100644
--- a/block/Makefile
+++ b/block/Makefile
@@ -41,3 +41,4 @@ obj-$(CONFIG_BLK_SED_OPAL) += sed-opal.o
obj-$(CONFIG_BLK_PM) += blk-pm.o
obj-$(CONFIG_BLK_INLINE_ENCRYPTION) += keyslot-manager.o blk-crypto.o
obj-$(CONFIG_BLK_INLINE_ENCRYPTION_FALLBACK) += blk-crypto-fallback.o
+obj-$(CONFIG_BLOCK_HOLDER_DEPRECATED) += holder.o
diff --git a/block/holder.c b/block/holder.c
new file mode 100644
index 000000000000..904a1dcd5c12
--- /dev/null
+++ b/block/holder.c
@@ -0,0 +1,139 @@
+// SPDX-License-Identifier: GPL-2.0-only
+#include <linux/genhd.h>
+
+struct bd_holder_disk {
+ struct list_head list;
+ struct gendisk *disk;
+ int refcnt;
+};
+
+static struct bd_holder_disk *bd_find_holder_disk(struct block_device *bdev,
+ struct gendisk *disk)
+{
+ struct bd_holder_disk *holder;
+
+ list_for_each_entry(holder, &bdev->bd_holder_disks, list)
+ if (holder->disk == disk)
+ return holder;
+ return NULL;
+}
+
+static int add_symlink(struct kobject *from, struct kobject *to)
+{
+ return sysfs_create_link(from, to, kobject_name(to));
+}
+
+static void del_symlink(struct kobject *from, struct kobject *to)
+{
+ sysfs_remove_link(from, kobject_name(to));
+}
+
+/**
+ * bd_link_disk_holder - create symlinks between holding disk and slave bdev
+ * @bdev: the claimed slave bdev
+ * @disk: the holding disk
+ *
+ * DON'T USE THIS UNLESS YOU'RE ALREADY USING IT.
+ *
+ * This functions creates the following sysfs symlinks.
+ *
+ * - from "slaves" directory of the holder @disk to the claimed @bdev
+ * - from "holders" directory of the @bdev to the holder @disk
+ *
+ * For example, if /dev/dm-0 maps to /dev/sda and disk for dm-0 is
+ * passed to bd_link_disk_holder(), then:
+ *
+ * /sys/block/dm-0/slaves/sda --> /sys/block/sda
+ * /sys/block/sda/holders/dm-0 --> /sys/block/dm-0
+ *
+ * The caller must have claimed @bdev before calling this function and
+ * ensure that both @bdev and @disk are valid during the creation and
+ * lifetime of these symlinks.
+ *
+ * CONTEXT:
+ * Might sleep.
+ *
+ * RETURNS:
+ * 0 on success, -errno on failure.
+ */
+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);
+
+ WARN_ON_ONCE(!bdev->bd_holder);
+
+ /* FIXME: remove the following once add_disk() handles errors */
+ if (WARN_ON(!disk->slave_dir || !bdev->bd_holder_dir))
+ goto out_unlock;
+
+ holder = bd_find_holder_disk(bdev, disk);
+ if (holder) {
+ holder->refcnt++;
+ goto out_unlock;
+ }
+
+ holder = kzalloc(sizeof(*holder), GFP_KERNEL);
+ if (!holder) {
+ ret = -ENOMEM;
+ goto out_unlock;
+ }
+
+ INIT_LIST_HEAD(&holder->list);
+ holder->disk = disk;
+ holder->refcnt = 1;
+
+ ret = add_symlink(disk->slave_dir, bdev_kobj(bdev));
+ if (ret)
+ goto out_free;
+
+ ret = add_symlink(bdev->bd_holder_dir, &disk_to_dev(disk)->kobj);
+ if (ret)
+ goto out_del;
+ /*
+ * bdev could be deleted beneath us which would implicitly destroy
+ * the holder directory. Hold on to it.
+ */
+ kobject_get(bdev->bd_holder_dir);
+
+ list_add(&holder->list, &bdev->bd_holder_disks);
+ goto out_unlock;
+
+out_del:
+ del_symlink(disk->slave_dir, bdev_kobj(bdev));
+out_free:
+ kfree(holder);
+out_unlock:
+ mutex_unlock(&bdev->bd_disk->open_mutex);
+ return ret;
+}
+EXPORT_SYMBOL_GPL(bd_link_disk_holder);
+
+/**
+ * bd_unlink_disk_holder - destroy symlinks created by bd_link_disk_holder()
+ * @bdev: the calimed slave bdev
+ * @disk: the holding disk
+ *
+ * DON'T USE THIS UNLESS YOU'RE ALREADY USING IT.
+ *
+ * CONTEXT:
+ * Might sleep.
+ */
+void bd_unlink_disk_holder(struct block_device *bdev, struct gendisk *disk)
+{
+ struct bd_holder_disk *holder;
+
+ mutex_lock(&bdev->bd_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));
+ del_symlink(bdev->bd_holder_dir, &disk_to_dev(disk)->kobj);
+ kobject_put(bdev->bd_holder_dir);
+ list_del_init(&holder->list);
+ kfree(holder);
+ }
+ mutex_unlock(&bdev->bd_disk->open_mutex);
+}
+EXPORT_SYMBOL_GPL(bd_unlink_disk_holder);
diff --git a/drivers/md/Kconfig b/drivers/md/Kconfig
index 0602e82a9516..f821dae101a9 100644
--- a/drivers/md/Kconfig
+++ b/drivers/md/Kconfig
@@ -15,6 +15,7 @@ if MD
config BLK_DEV_MD
tristate "RAID support"
+ select BLOCK_HOLDER_DEPRECATED if SYSFS
help
This driver lets you combine several hard disk partitions into one
logical block device. This can be used to simply append one
@@ -201,6 +202,7 @@ config BLK_DEV_DM_BUILTIN
config BLK_DEV_DM
tristate "Device mapper support"
+ select BLOCK_HOLDER_DEPRECATED if SYSFS
select BLK_DEV_DM_BUILTIN
depends on DAX || DAX=n
help
diff --git a/drivers/md/bcache/Kconfig b/drivers/md/bcache/Kconfig
index d1ca4d059c20..cf3e8096942a 100644
--- a/drivers/md/bcache/Kconfig
+++ b/drivers/md/bcache/Kconfig
@@ -2,6 +2,7 @@
config BCACHE
tristate "Block device as cache"
+ select BLOCK_HOLDER_DEPRECATED if SYSFS
select CRC64
help
Allows a block device to be used as cache for other devices; uses
diff --git a/fs/block_dev.c b/fs/block_dev.c
index 6658f40ae492..ae9651cad923 100644
--- a/fs/block_dev.c
+++ b/fs/block_dev.c
@@ -902,7 +902,7 @@ struct block_device *bdev_alloc(struct gendisk *disk, u8 partno)
bdev->bd_disk = disk;
bdev->bd_partno = partno;
bdev->bd_inode = inode;
-#ifdef CONFIG_SYSFS
+#ifdef CONFIG_BLOCK_HOLDER_DEPRECATED
INIT_LIST_HEAD(&bdev->bd_holder_disks);
#endif
bdev->bd_stats = alloc_percpu(struct disk_stats);
@@ -1063,148 +1063,6 @@ void bd_abort_claiming(struct block_device *bdev, void *holder)
}
EXPORT_SYMBOL(bd_abort_claiming);
-#ifdef CONFIG_SYSFS
-struct bd_holder_disk {
- struct list_head list;
- struct gendisk *disk;
- int refcnt;
-};
-
-static struct bd_holder_disk *bd_find_holder_disk(struct block_device *bdev,
- struct gendisk *disk)
-{
- struct bd_holder_disk *holder;
-
- list_for_each_entry(holder, &bdev->bd_holder_disks, list)
- if (holder->disk == disk)
- return holder;
- return NULL;
-}
-
-static int add_symlink(struct kobject *from, struct kobject *to)
-{
- return sysfs_create_link(from, to, kobject_name(to));
-}
-
-static void del_symlink(struct kobject *from, struct kobject *to)
-{
- sysfs_remove_link(from, kobject_name(to));
-}
-
-/**
- * bd_link_disk_holder - create symlinks between holding disk and slave bdev
- * @bdev: the claimed slave bdev
- * @disk: the holding disk
- *
- * DON'T USE THIS UNLESS YOU'RE ALREADY USING IT.
- *
- * This functions creates the following sysfs symlinks.
- *
- * - from "slaves" directory of the holder @disk to the claimed @bdev
- * - from "holders" directory of the @bdev to the holder @disk
- *
- * For example, if /dev/dm-0 maps to /dev/sda and disk for dm-0 is
- * passed to bd_link_disk_holder(), then:
- *
- * /sys/block/dm-0/slaves/sda --> /sys/block/sda
- * /sys/block/sda/holders/dm-0 --> /sys/block/dm-0
- *
- * The caller must have claimed @bdev before calling this function and
- * ensure that both @bdev and @disk are valid during the creation and
- * lifetime of these symlinks.
- *
- * CONTEXT:
- * Might sleep.
- *
- * RETURNS:
- * 0 on success, -errno on failure.
- */
-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);
-
- WARN_ON_ONCE(!bdev->bd_holder);
-
- /* FIXME: remove the following once add_disk() handles errors */
- if (WARN_ON(!disk->slave_dir || !bdev->bd_holder_dir))
- goto out_unlock;
-
- holder = bd_find_holder_disk(bdev, disk);
- if (holder) {
- holder->refcnt++;
- goto out_unlock;
- }
-
- holder = kzalloc(sizeof(*holder), GFP_KERNEL);
- if (!holder) {
- ret = -ENOMEM;
- goto out_unlock;
- }
-
- INIT_LIST_HEAD(&holder->list);
- holder->disk = disk;
- holder->refcnt = 1;
-
- ret = add_symlink(disk->slave_dir, bdev_kobj(bdev));
- if (ret)
- goto out_free;
-
- ret = add_symlink(bdev->bd_holder_dir, &disk_to_dev(disk)->kobj);
- if (ret)
- goto out_del;
- /*
- * bdev could be deleted beneath us which would implicitly destroy
- * the holder directory. Hold on to it.
- */
- kobject_get(bdev->bd_holder_dir);
-
- list_add(&holder->list, &bdev->bd_holder_disks);
- goto out_unlock;
-
-out_del:
- del_symlink(disk->slave_dir, bdev_kobj(bdev));
-out_free:
- kfree(holder);
-out_unlock:
- mutex_unlock(&bdev->bd_disk->open_mutex);
- return ret;
-}
-EXPORT_SYMBOL_GPL(bd_link_disk_holder);
-
-/**
- * bd_unlink_disk_holder - destroy symlinks created by bd_link_disk_holder()
- * @bdev: the calimed slave bdev
- * @disk: the holding disk
- *
- * DON'T USE THIS UNLESS YOU'RE ALREADY USING IT.
- *
- * CONTEXT:
- * Might sleep.
- */
-void bd_unlink_disk_holder(struct block_device *bdev, struct gendisk *disk)
-{
- struct bd_holder_disk *holder;
-
- mutex_lock(&bdev->bd_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));
- del_symlink(bdev->bd_holder_dir, &disk_to_dev(disk)->kobj);
- kobject_put(bdev->bd_holder_dir);
- list_del_init(&holder->list);
- kfree(holder);
- }
-
- mutex_unlock(&bdev->bd_disk->open_mutex);
-}
-EXPORT_SYMBOL_GPL(bd_unlink_disk_holder);
-#endif
-
static void blkdev_flush_mapping(struct block_device *bdev)
{
WARN_ON_ONCE(bdev->bd_holders);
diff --git a/include/linux/blk_types.h b/include/linux/blk_types.h
index 290f9061b29a..7a4e139d24ef 100644
--- a/include/linux/blk_types.h
+++ b/include/linux/blk_types.h
@@ -34,7 +34,7 @@ struct block_device {
void * bd_holder;
int bd_holders;
bool bd_write_holder;
-#ifdef CONFIG_SYSFS
+#ifdef CONFIG_BLOCK_HOLDER_DEPRECATED
struct list_head bd_holder_disks;
#endif
struct kobject *bd_holder_dir;
diff --git a/include/linux/genhd.h b/include/linux/genhd.h
index 849486de81c6..e21a91c16a79 100644
--- a/include/linux/genhd.h
+++ b/include/linux/genhd.h
@@ -318,7 +318,7 @@ void set_capacity(struct gendisk *disk, sector_t size);
int blkdev_ioctl(struct block_device *, fmode_t, unsigned, unsigned long);
long compat_blkdev_ioctl(struct file *, unsigned, unsigned long);
-#ifdef CONFIG_SYSFS
+#ifdef CONFIG_BLOCK_HOLDER_DEPRECATED
int bd_link_disk_holder(struct block_device *bdev, struct gendisk *disk);
void bd_unlink_disk_holder(struct block_device *bdev, struct gendisk *disk);
#else
@@ -331,7 +331,7 @@ static inline void bd_unlink_disk_holder(struct block_device *bdev,
struct gendisk *disk)
{
}
-#endif /* CONFIG_SYSFS */
+#endif /* CONFIG_BLOCK_HOLDER_DEPRECATED */
dev_t part_devt(struct gendisk *disk, u8 partno);
void inc_diskseq(struct gendisk *disk);
--
2.30.2
