mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-08-25 02:09:42 +00:00
![Christoph Hellwig](/assets/img/avatar_default.png)
Drop various include not actually used in genhd.h itself, and move the remaning includes closer together. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Link: https://lore.kernel.org/r/20210920123328.1399408-15-hch@lst.de Signed-off-by: Jens Axboe <axboe@kernel.dk>
175 lines
4.2 KiB
C
175 lines
4.2 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
|
|
#include <linux/genhd.h>
|
|
#include <linux/slab.h>
|
|
|
|
struct bd_holder_disk {
|
|
struct list_head list;
|
|
struct block_device *bdev;
|
|
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, &disk->slave_bdevs, list)
|
|
if (holder->bdev == bdev)
|
|
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));
|
|
}
|
|
|
|
static int __link_disk_holder(struct block_device *bdev, struct gendisk *disk)
|
|
{
|
|
int ret;
|
|
|
|
ret = add_symlink(disk->slave_dir, bdev_kobj(bdev));
|
|
if (ret)
|
|
return ret;
|
|
ret = add_symlink(bdev->bd_holder_dir, &disk_to_dev(disk)->kobj);
|
|
if (ret)
|
|
del_symlink(disk->slave_dir, bdev_kobj(bdev));
|
|
return ret;
|
|
}
|
|
|
|
/**
|
|
* 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(&disk->open_mutex);
|
|
|
|
WARN_ON_ONCE(!bdev->bd_holder);
|
|
|
|
/* FIXME: remove the following once add_disk() handles errors */
|
|
if (WARN_ON(!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->bdev = bdev;
|
|
holder->refcnt = 1;
|
|
if (disk->slave_dir) {
|
|
ret = __link_disk_holder(bdev, disk);
|
|
if (ret) {
|
|
kfree(holder);
|
|
goto out_unlock;
|
|
}
|
|
}
|
|
|
|
list_add(&holder->list, &disk->slave_bdevs);
|
|
/*
|
|
* del_gendisk drops the initial reference to bd_holder_dir, so we need
|
|
* to keep our own here to allow for cleanup past that point.
|
|
*/
|
|
kobject_get(bdev->bd_holder_dir);
|
|
|
|
out_unlock:
|
|
mutex_unlock(&disk->open_mutex);
|
|
return ret;
|
|
}
|
|
EXPORT_SYMBOL_GPL(bd_link_disk_holder);
|
|
|
|
static void __unlink_disk_holder(struct block_device *bdev,
|
|
struct gendisk *disk)
|
|
{
|
|
del_symlink(disk->slave_dir, bdev_kobj(bdev));
|
|
del_symlink(bdev->bd_holder_dir, &disk_to_dev(disk)->kobj);
|
|
}
|
|
|
|
/**
|
|
* 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(&disk->open_mutex);
|
|
holder = bd_find_holder_disk(bdev, disk);
|
|
if (!WARN_ON_ONCE(holder == NULL) && !--holder->refcnt) {
|
|
if (disk->slave_dir)
|
|
__unlink_disk_holder(bdev, disk);
|
|
kobject_put(bdev->bd_holder_dir);
|
|
list_del_init(&holder->list);
|
|
kfree(holder);
|
|
}
|
|
mutex_unlock(&disk->open_mutex);
|
|
}
|
|
EXPORT_SYMBOL_GPL(bd_unlink_disk_holder);
|
|
|
|
int bd_register_pending_holders(struct gendisk *disk)
|
|
{
|
|
struct bd_holder_disk *holder;
|
|
int ret;
|
|
|
|
mutex_lock(&disk->open_mutex);
|
|
list_for_each_entry(holder, &disk->slave_bdevs, list) {
|
|
ret = __link_disk_holder(holder->bdev, disk);
|
|
if (ret)
|
|
goto out_undo;
|
|
}
|
|
mutex_unlock(&disk->open_mutex);
|
|
return 0;
|
|
|
|
out_undo:
|
|
list_for_each_entry_continue_reverse(holder, &disk->slave_bdevs, list)
|
|
__unlink_disk_holder(holder->bdev, disk);
|
|
mutex_unlock(&disk->open_mutex);
|
|
return ret;
|
|
}
|