Allocate hd_struct together with struct block_device to pre-load
the lifetime rule changes in preparation of merging the two structures.

Note that part0 was previously embedded into struct gendisk, but is
a separate allocation now, and already points to the block_device instead
of the hd_struct.  The lifetime of struct gendisk is still controlled by
the struct device embedded in the part0 hd_struct.

Signed-off-by: Christoph Hellwig <h...@lst.de>
---
 block/blk-core.c                   | 16 ++++---
 block/blk-flush.c                  |  2 +-
 block/blk-merge.c                  |  2 -
 block/blk.h                        | 21 ----------
 block/genhd.c                      | 50 +++++++++-------------
 block/partitions/core.c            | 67 +++---------------------------
 drivers/block/drbd/drbd_receiver.c |  2 +-
 drivers/block/drbd/drbd_worker.c   |  3 +-
 drivers/block/zram/zram_drv.c      |  2 +-
 drivers/md/dm.c                    |  4 +-
 drivers/md/md.c                    |  2 +-
 fs/block_dev.c                     | 39 ++++++-----------
 include/linux/blk_types.h          |  2 +-
 include/linux/genhd.h              | 14 +++----
 include/linux/part_stat.h          |  4 +-
 15 files changed, 61 insertions(+), 169 deletions(-)

diff --git a/block/blk-core.c b/block/blk-core.c
index d64ffcb6f9ae5d..9ea70275fc1cfe 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -714,7 +714,8 @@ static inline bool bio_check_ro(struct bio *bio, struct 
hd_struct *part)
 
 static noinline int should_fail_bio(struct bio *bio)
 {
-       if (should_fail_request(&bio->bi_disk->part0, bio->bi_iter.bi_size))
+       if (should_fail_request(bio->bi_disk->part0->bd_part,
+                       bio->bi_iter.bi_size))
                return -EIO;
        return 0;
 }
@@ -831,7 +832,7 @@ static noinline_for_stack bool submit_bio_checks(struct bio 
*bio)
                if (unlikely(blk_partition_remap(bio)))
                        goto end_io;
        } else {
-               if (unlikely(bio_check_ro(bio, &bio->bi_disk->part0)))
+               if (unlikely(bio_check_ro(bio, bio->bi_disk->part0->bd_part)))
                        goto end_io;
                if (unlikely(bio_check_eod(bio, get_capacity(bio->bi_disk))))
                        goto end_io;
@@ -1203,7 +1204,7 @@ blk_status_t blk_insert_cloned_request(struct 
request_queue *q, struct request *
                return ret;
 
        if (rq->rq_disk &&
-           should_fail_request(&rq->rq_disk->part0, blk_rq_bytes(rq)))
+           should_fail_request(rq->rq_disk->part0->bd_part, blk_rq_bytes(rq)))
                return BLK_STS_IOERR;
 
        if (blk_crypto_insert_cloned_request(rq))
@@ -1272,7 +1273,7 @@ static void update_io_ticks(struct hd_struct *part, 
unsigned long now, bool end)
                        __part_stat_add(part, io_ticks, end ? now - stamp : 1);
        }
        if (part->partno) {
-               part = &part_to_disk(part)->part0;
+               part = part_to_disk(part)->part0->bd_part;
                goto again;
        }
 }
@@ -1309,8 +1310,6 @@ void blk_account_io_done(struct request *req, u64 now)
                part_stat_inc(part, ios[sgrp]);
                part_stat_add(part, nsecs[sgrp], now - req->start_time_ns);
                part_stat_unlock();
-
-               hd_struct_put(part);
        }
 }
 
@@ -1354,7 +1353,7 @@ EXPORT_SYMBOL_GPL(part_start_io_acct);
 unsigned long disk_start_io_acct(struct gendisk *disk, unsigned int sectors,
                                 unsigned int op)
 {
-       return __part_start_io_acct(&disk->part0, sectors, op);
+       return __part_start_io_acct(disk->part0->bd_part, sectors, op);
 }
 EXPORT_SYMBOL(disk_start_io_acct);
 
@@ -1376,14 +1375,13 @@ void part_end_io_acct(struct hd_struct *part, struct 
bio *bio,
                      unsigned long start_time)
 {
        __part_end_io_acct(part, bio_op(bio), start_time);
-       hd_struct_put(part);
 }
 EXPORT_SYMBOL_GPL(part_end_io_acct);
 
 void disk_end_io_acct(struct gendisk *disk, unsigned int op,
                      unsigned long start_time)
 {
-       __part_end_io_acct(&disk->part0, op, start_time);
+       __part_end_io_acct(disk->part0->bd_part, op, start_time);
 }
 EXPORT_SYMBOL(disk_end_io_acct);
 
diff --git a/block/blk-flush.c b/block/blk-flush.c
index e32958f0b68750..fcd0a60574dff8 100644
--- a/block/blk-flush.c
+++ b/block/blk-flush.c
@@ -139,7 +139,7 @@ static void blk_flush_queue_rq(struct request *rq, bool 
add_front)
 
 static void blk_account_io_flush(struct request *rq)
 {
-       struct hd_struct *part = &rq->rq_disk->part0;
+       struct hd_struct *part = rq->rq_disk->part0->bd_part;
 
        part_stat_lock();
        part_stat_inc(part, ios[STAT_FLUSH]);
diff --git a/block/blk-merge.c b/block/blk-merge.c
index bcf5e458060337..cb351ab9b77dbd 100644
--- a/block/blk-merge.c
+++ b/block/blk-merge.c
@@ -683,8 +683,6 @@ static void blk_account_io_merge_request(struct request 
*req)
                part_stat_lock();
                part_stat_inc(req->part, merges[op_stat_group(req_op(req))]);
                part_stat_unlock();
-
-               hd_struct_put(req->part);
        }
 }
 
diff --git a/block/blk.h b/block/blk.h
index 0bd4b58bcbaf77..32ac41f7557fcc 100644
--- a/block/blk.h
+++ b/block/blk.h
@@ -363,27 +363,6 @@ int bdev_del_partition(struct block_device *bdev, int 
partno);
 int bdev_resize_partition(struct block_device *bdev, int partno,
                sector_t start, sector_t length);
 int disk_expand_part_tbl(struct gendisk *disk, int target);
-int hd_ref_init(struct hd_struct *part);
-
-/* no need to get/put refcount of part0 */
-static inline int hd_struct_try_get(struct hd_struct *part)
-{
-       if (part->partno)
-               return percpu_ref_tryget_live(&part->ref);
-       return 1;
-}
-
-static inline void hd_struct_put(struct hd_struct *part)
-{
-       if (part->partno)
-               percpu_ref_put(&part->ref);
-}
-
-static inline void hd_free_part(struct hd_struct *part)
-{
-       bdput(part->bdev);
-       percpu_ref_exit(&part->ref);
-}
 
 int bio_add_hw_page(struct request_queue *q, struct bio *bio,
                struct page *page, unsigned int len, unsigned int offset,
diff --git a/block/genhd.c b/block/genhd.c
index ae312ccc6dd7c0..eaa5d65ae826b8 100644
--- a/block/genhd.c
+++ b/block/genhd.c
@@ -42,7 +42,7 @@ static void disk_release_events(struct gendisk *disk);
 
 void set_capacity(struct gendisk *disk, sector_t sectors)
 {
-       struct block_device *bdev = disk->part0.bdev;
+       struct block_device *bdev = disk->part0;
 
        spin_lock(&bdev->bd_size_lock);
        i_size_write(bdev->bd_inode, (loff_t)sectors << SECTOR_SHIFT);
@@ -310,9 +310,7 @@ static inline int sector_in_part(struct hd_struct *part, 
sector_t sector)
  * primarily used for stats accounting.
  *
  * CONTEXT:
- * RCU read locked.  The returned partition pointer is always valid
- * because its refcount is grabbed except for part0, which lifetime
- * is same with the disk.
+ * RCU read locked.
  *
  * RETURNS:
  * Found partition on success, part0 is returned if no partition matches
@@ -328,26 +326,19 @@ struct hd_struct *disk_map_sector_rcu(struct gendisk 
*disk, sector_t sector)
        ptbl = rcu_dereference(disk->part_tbl);
 
        part = rcu_dereference(ptbl->last_lookup);
-       if (part && sector_in_part(part, sector) && hd_struct_try_get(part))
+       if (part && sector_in_part(part, sector))
                goto out_unlock;
 
        for (i = 1; i < ptbl->len; i++) {
                part = rcu_dereference(ptbl->part[i]);
 
                if (part && sector_in_part(part, sector)) {
-                       /*
-                        * only live partition can be cached for lookup,
-                        * so use-after-free on cached & deleting partition
-                        * can be avoided
-                        */
-                       if (!hd_struct_try_get(part))
-                               break;
                        rcu_assign_pointer(ptbl->last_lookup, part);
                        goto out_unlock;
                }
        }
 
-       part = &disk->part0;
+       part = disk->part0->bd_part;
 out_unlock:
        rcu_read_unlock();
        return part;
@@ -673,8 +664,8 @@ static void register_disk(struct device *parent, struct 
gendisk *disk,
         */
        pm_runtime_set_memalloc_noio(ddev, true);
 
-       disk->part0.bdev->bd_holder_dir =
-                       kobject_create_and_add("holders", &ddev->kobj);
+       disk->part0->bd_holder_dir =
+               kobject_create_and_add("holders", &ddev->kobj);
        disk->slave_dir = kobject_create_and_add("slaves", &ddev->kobj);
 
        if (disk->flags & GENHD_FL_HIDDEN) {
@@ -740,7 +731,7 @@ static void __device_add_disk(struct device *parent, struct 
gendisk *disk,
 
        disk->flags |= GENHD_FL_UP;
 
-       retval = blk_alloc_devt(&disk->part0, &devt);
+       retval = blk_alloc_devt(disk->part0->bd_part, &devt);
        if (retval) {
                WARN_ON(1);
                return;
@@ -767,7 +758,7 @@ static void __device_add_disk(struct device *parent, struct 
gendisk *disk,
                ret = bdi_register(bdi, "%u:%u", MAJOR(devt), MINOR(devt));
                WARN_ON(ret);
                bdi_set_owner(bdi, dev);
-               bdev_add(disk->part0.bdev, devt);
+               bdev_add(disk->part0, devt);
        }
        register_disk(parent, disk, groups);
        if (register_queue)
@@ -880,11 +871,11 @@ void del_gendisk(struct gendisk *disk)
 
        blk_unregister_queue(disk);
 
-       kobject_put(disk->part0.bdev->bd_holder_dir);
+       kobject_put(disk->part0->bd_holder_dir);
        kobject_put(disk->slave_dir);
 
-       part_stat_set_all(&disk->part0, 0);
-       disk->part0.bdev->bd_stamp = 0;
+       part_stat_set_all(disk->part0->bd_part, 0);
+       disk->part0->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);
@@ -997,7 +988,7 @@ void __init printk_all_partitions(void)
                 */
                disk_part_iter_init(&piter, disk, DISK_PITER_INCL_PART0);
                while ((part = disk_part_iter_next(&piter))) {
-                       bool is_part0 = part == &disk->part0;
+                       bool is_part0 = part == disk->part0->bd_part;
 
                        printk("%s%s %10llu %s %s", is_part0 ? "" : "  ",
                               bdevt_str(part_devt(part), devt_buf),
@@ -1452,7 +1443,7 @@ static void disk_release(struct device *dev)
        disk_release_events(disk);
        kfree(disk->random);
        disk_replace_part_tbl(disk, NULL);
-       hd_free_part(&disk->part0);
+       bdput(disk->part0);
        if (disk->queue)
                blk_put_queue(disk->queue);
        kfree(disk);
@@ -1618,8 +1609,8 @@ struct gendisk *__alloc_disk_node(int minors, int node_id)
        if (!disk)
                return NULL;
 
-       disk->part0.bdev = bdev_alloc(disk, 0);
-       if (!disk->part0.bdev)
+       disk->part0 = bdev_alloc(disk, 0);
+       if (!disk->part0)
                goto out_free_disk;
 
        disk->node_id = node_id;
@@ -1627,10 +1618,7 @@ struct gendisk *__alloc_disk_node(int minors, int 
node_id)
                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_bdput;
+       rcu_assign_pointer(ptbl->part[0], disk->part0->bd_part);
 
        disk->minors = minors;
        rand_initialize_disk(disk);
@@ -1640,7 +1628,7 @@ struct gendisk *__alloc_disk_node(int minors, int node_id)
        return disk;
 
 out_bdput:
-       bdput(disk->part0.bdev);
+       bdput(disk->part0);
 out_free_disk:
        kfree(disk);
        return NULL;
@@ -1679,9 +1667,9 @@ void set_disk_ro(struct gendisk *disk, int flag)
        struct disk_part_iter piter;
        struct hd_struct *part;
 
-       if (disk->part0.bdev->bd_read_only != flag) {
+       if (disk->part0->bd_read_only != flag) {
                set_disk_ro_uevent(disk, flag);
-               disk->part0.bdev->bd_read_only = flag;
+               disk->part0->bd_read_only = flag;
        }
 
        disk_part_iter_init(&piter, disk, DISK_PITER_INCL_EMPTY);
diff --git a/block/partitions/core.c b/block/partitions/core.c
index 060c1be13cd8da..6d1fca193cbd6f 100644
--- a/block/partitions/core.c
+++ b/block/partitions/core.c
@@ -265,9 +265,9 @@ static const struct attribute_group *part_attr_groups[] = {
 static void part_release(struct device *dev)
 {
        struct hd_struct *p = dev_to_part(dev);
+
        blk_free_devt(dev->devt);
-       hd_free_part(p);
-       kfree(p);
+       bdput(p->bdev);
 }
 
 static int part_uevent(struct device *dev, struct kobj_uevent_env *env)
@@ -288,46 +288,6 @@ struct device_type part_type = {
        .uevent         = part_uevent,
 };
 
-static void hd_struct_free_work(struct work_struct *work)
-{
-       struct hd_struct *part =
-               container_of(to_rcu_work(work), struct hd_struct, rcu_work);
-       struct gendisk *disk = part_to_disk(part);
-
-       /*
-        * Release the disk reference acquired in delete_partition here.
-        * We can't release it in hd_struct_free because the final put_device
-        * needs process context and thus can't be run directly from a
-        * percpu_ref ->release handler.
-        */
-       put_device(disk_to_dev(disk));
-
-       part->bdev->bd_start_sect = 0;
-       bdev_set_nr_sectors(part->bdev, 0);
-       part_stat_set_all(part, 0);
-       put_device(part_to_dev(part));
-}
-
-static void hd_struct_free(struct percpu_ref *ref)
-{
-       struct hd_struct *part = container_of(ref, struct hd_struct, ref);
-       struct gendisk *disk = part_to_disk(part);
-       struct disk_part_tbl *ptbl =
-               rcu_dereference_protected(disk->part_tbl, 1);
-
-       rcu_assign_pointer(ptbl->last_lookup, NULL);
-
-       INIT_RCU_WORK(&part->rcu_work, hd_struct_free_work);
-       queue_rcu_work(system_wq, &part->rcu_work);
-}
-
-int hd_ref_init(struct hd_struct *part)
-{
-       if (percpu_ref_init(&part->ref, hd_struct_free, 0, GFP_KERNEL))
-               return -ENOMEM;
-       return 0;
-}
-
 /*
  * Must be called either with bd_mutex held, before a disk can be opened or
  * after all disk users are gone.
@@ -342,8 +302,8 @@ void delete_partition(struct hd_struct *part)
         * ->part_tbl is referenced in this part's release handler, so
         *  we have to hold the disk device
         */
-       get_device(disk_to_dev(disk));
        rcu_assign_pointer(ptbl->part[part->partno], NULL);
+       rcu_assign_pointer(ptbl->last_lookup, NULL);
        kobject_put(part->bdev->bd_holder_dir);
        device_del(part_to_dev(part));
 
@@ -353,7 +313,7 @@ void delete_partition(struct hd_struct *part)
         */
        remove_inode_hash(part->bdev->bd_inode);
 
-       percpu_ref_kill(&part->ref);
+       put_device(part_to_dev(part));
 }
 
 static ssize_t whole_disk_show(struct device *dev,
@@ -406,15 +366,11 @@ static struct hd_struct *add_partition(struct gendisk 
*disk, int partno,
        if (ptbl->part[partno])
                return ERR_PTR(-EBUSY);
 
-       p = kzalloc(sizeof(*p), GFP_KERNEL);
-       if (!p)
-               return ERR_PTR(-EBUSY);
-
        bdev = bdev_alloc(disk, partno);
        if (!bdev)
-               goto out_free;
-       p->bdev = bdev;
+               return ERR_PTR(-ENOMEM);
 
+       p = bdev->bd_part;
        pdev = part_to_dev(p);
 
        bdev->bd_start_sect = start;
@@ -463,13 +419,6 @@ static struct hd_struct *add_partition(struct gendisk 
*disk, int partno,
                        goto out_del;
        }
 
-       err = hd_ref_init(p);
-       if (err) {
-               if (flags & ADDPART_FLAG_WHOLEDISK)
-                       goto out_remove_file;
-               goto out_del;
-       }
-
        /* everything is up and running, commence */
        bdev_add(bdev, devt);
        rcu_assign_pointer(ptbl->part[partno], p);
@@ -481,11 +430,7 @@ static struct hd_struct *add_partition(struct gendisk 
*disk, int partno,
 
 out_bdput:
        bdput(bdev);
-out_free:
-       kfree(p);
        return ERR_PTR(err);
-out_remove_file:
-       device_remove_file(pdev, &dev_attr_whole_disk);
 out_del:
        kobject_put(bdev->bd_holder_dir);
        device_del(pdev);
diff --git a/drivers/block/drbd/drbd_receiver.c 
b/drivers/block/drbd/drbd_receiver.c
index dc333dbe523281..9e5c2fdfda3629 100644
--- a/drivers/block/drbd/drbd_receiver.c
+++ b/drivers/block/drbd/drbd_receiver.c
@@ -2802,7 +2802,7 @@ bool drbd_rs_c_min_rate_throttle(struct drbd_device 
*device)
        if (c_min_rate == 0)
                return false;
 
-       curr_events = (int)part_stat_read_accum(&disk->part0, sectors) -
+       curr_events = (int)part_stat_read_accum(disk->part0->bd_part, sectors) -
                        atomic_read(&device->rs_sect_ev);
 
        if (atomic_read(&device->ap_actlog_cnt)
diff --git a/drivers/block/drbd/drbd_worker.c b/drivers/block/drbd/drbd_worker.c
index ba56f3f05312f0..343f56b86bb766 100644
--- a/drivers/block/drbd/drbd_worker.c
+++ b/drivers/block/drbd/drbd_worker.c
@@ -1678,7 +1678,8 @@ void drbd_rs_controller_reset(struct drbd_device *device)
        atomic_set(&device->rs_sect_in, 0);
        atomic_set(&device->rs_sect_ev, 0);
        device->rs_in_flight = 0;
-       device->rs_last_events = (int)part_stat_read_accum(&disk->part0, 
sectors);
+       device->rs_last_events =
+               (int)part_stat_read_accum(disk->part0->bd_part, sectors);
 
        /* Updating the RCU protected object in place is necessary since
           this function gets called from atomic context.
diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c
index b5f68951c9d280..6d84876a9cd0ae 100644
--- a/drivers/block/zram/zram_drv.c
+++ b/drivers/block/zram/zram_drv.c
@@ -1687,7 +1687,7 @@ static void zram_reset_device(struct zram *zram)
        zram->disksize = 0;
 
        set_capacity_and_notify(zram->disk, 0);
-       part_stat_set_all(&zram->disk->part0, 0);
+       part_stat_set_all(zram->disk->part0->bd_part, 0);
 
        up_write(&zram->init_lock);
        /* I/O operation under all of CPU are done so let's free */
diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index 48051db006f30c..1b2db4d530ea71 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -1607,7 +1607,7 @@ static blk_qc_t __split_and_process_bio(struct 
mapped_device *md,
                                 * (by eliminating DM's splitting and just 
using bio_split)
                                 */
                                part_stat_lock();
-                               __dm_part_stat_sub(&dm_disk(md)->part0,
+                               __dm_part_stat_sub(dm_disk(md)->part0->bd_part,
                                                   
sectors[op_stat_group(bio_op(bio))], ci.sector_count);
                                part_stat_unlock();
 
@@ -2242,7 +2242,7 @@ EXPORT_SYMBOL_GPL(dm_put);
 static bool md_in_flight_bios(struct mapped_device *md)
 {
        int cpu;
-       struct hd_struct *part = &dm_disk(md)->part0;
+       struct hd_struct *part = dm_disk(md)->part0->bd_part;
        long sum = 0;
 
        for_each_possible_cpu(cpu) {
diff --git a/drivers/md/md.c b/drivers/md/md.c
index 7ce6047c856ea2..3696c2d77a4dd7 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -8441,7 +8441,7 @@ static int is_mddev_idle(struct mddev *mddev, int init)
        rcu_read_lock();
        rdev_for_each_rcu(rdev, mddev) {
                struct gendisk *disk = rdev->bdev->bd_disk;
-               curr_events = (int)part_stat_read_accum(&disk->part0, sectors) -
+               curr_events = (int)part_stat_read_accum(disk->part0->bd_part, 
sectors) -
                              atomic_read(&disk->sync_io);
                /* sync IO will cause sync_io to increase before the disk_stats
                 * as sync_io is counted when a request starts, and
diff --git a/fs/block_dev.c b/fs/block_dev.c
index 381c22426f435b..61cf33b6284feb 100644
--- a/fs/block_dev.c
+++ b/fs/block_dev.c
@@ -39,6 +39,7 @@
 
 struct bdev_inode {
        struct block_device bdev;
+       struct hd_struct hd;
        struct inode vfs_inode;
 };
 
@@ -886,6 +887,9 @@ struct block_device *bdev_alloc(struct gendisk *disk, u8 
partno)
                iput(inode);
                return NULL;
        }
+       bdev->bd_part = &BDEV_I(inode)->hd;
+       memset(bdev->bd_part, 0, sizeof(*bdev->bd_part));
+       bdev->bd_part->bdev = bdev;
        return bdev;
 }
 
@@ -1280,15 +1284,10 @@ EXPORT_SYMBOL_GPL(bdev_disk_changed);
 static int __blkdev_get(struct block_device *bdev, fmode_t mode)
 {
        struct gendisk *disk = bdev->bd_disk;
-       int ret;
+       int ret = 0;
 
        if (!bdev->bd_openers) {
                if (!bdev_is_partition(bdev)) {
-                       ret = -ENXIO;
-                       bdev->bd_part = disk_get_part(disk, 0);
-                       if (!bdev->bd_part)
-                               goto out_clear;
-
                        ret = 0;
                        if (disk->fops->open)
                                ret = disk->fops->open(bdev, mode);
@@ -1307,7 +1306,7 @@ static int __blkdev_get(struct block_device *bdev, 
fmode_t mode)
                                bdev_disk_changed(bdev, ret == -ENOMEDIUM);
 
                        if (ret)
-                               goto out_clear;
+                               return ret;
                } else {
                        struct block_device *whole = bdget_disk(disk, 0);
 
@@ -1316,18 +1315,16 @@ static int __blkdev_get(struct block_device *bdev, 
fmode_t mode)
                        if (ret) {
                                mutex_unlock(&whole->bd_mutex);
                                bdput(whole);
-                               goto out_clear;
+                               return ret;
                        }
                        whole->bd_part_count++;
                        mutex_unlock(&whole->bd_mutex);
 
-                       bdev->bd_part = disk_get_part(disk, bdev->bd_partno);
                        if (!(disk->flags & GENHD_FL_UP) ||
-                           !bdev->bd_part || !bdev_nr_sectors(bdev)) {
+                           !bdev_nr_sectors(bdev)) {
                                __blkdev_put(whole, mode, 1);
                                bdput(whole);
-                               ret = -ENXIO;
-                               goto out_clear;
+                               return -ENXIO;
                        }
                        set_init_blocksize(bdev);
                }
@@ -1336,7 +1333,6 @@ static int __blkdev_get(struct block_device *bdev, 
fmode_t mode)
                        bdev->bd_bdi = bdi_get(disk->queue->backing_dev_info);
        } else {
                if (!bdev_is_partition(bdev)) {
-                       ret = 0;
                        if (bdev->bd_disk->fops->open)
                                ret = bdev->bd_disk->fops->open(bdev, mode);
                        /* the same as first opener case, read comment there */
@@ -1349,11 +1345,6 @@ static int __blkdev_get(struct block_device *bdev, 
fmode_t mode)
        }
        bdev->bd_openers++;
        return 0;
-
- out_clear:
-       disk_put_part(bdev->bd_part);
-       bdev->bd_part = NULL;
-       return ret;
 }
 
 struct block_device *blkdev_get_no_open(dev_t dev)
@@ -1580,18 +1571,12 @@ static void __blkdev_put(struct block_device *bdev, 
fmode_t mode, int for_part)
                sync_blockdev(bdev);
                kill_bdev(bdev);
                bdev_write_inode(bdev);
-
-               if (!bdev_is_partition(bdev) && disk->fops->release)
-                       disk->fops->release(disk, mode);
-
-               disk_put_part(bdev->bd_part);
-               bdev->bd_part = NULL;
                if (bdev_is_partition(bdev))
                        victim = bdev_whole(bdev);
-       } else {
-               if (!bdev_is_partition(bdev) && disk->fops->release)
-                       disk->fops->release(disk, mode);
        }
+
+       if (!bdev_is_partition(bdev) && disk->fops->release)
+               disk->fops->release(disk, mode);
        mutex_unlock(&bdev->bd_mutex);
        if (victim) {
                __blkdev_put(victim, mode, 1);
diff --git a/include/linux/blk_types.h b/include/linux/blk_types.h
index 758cf71c9aa2a6..6edea5c1625909 100644
--- a/include/linux/blk_types.h
+++ b/include/linux/blk_types.h
@@ -59,7 +59,7 @@ struct block_device {
 } __randomize_layout;
 
 #define bdev_whole(_bdev) \
-       ((_bdev)->bd_disk->part0.bdev)
+       ((_bdev)->bd_disk->part0)
 
 #define bdev_kobj(_bdev) \
        (&part_to_dev((_bdev)->bd_part)->kobj)
diff --git a/include/linux/genhd.h b/include/linux/genhd.h
index dcbf9ef7610ea6..df7319da013ccf 100644
--- a/include/linux/genhd.h
+++ b/include/linux/genhd.h
@@ -19,11 +19,12 @@
 #include <linux/blk_types.h>
 #include <asm/local.h>
 
-#define dev_to_disk(device)    container_of((device), struct gendisk, 
part0.__dev)
 #define dev_to_part(device)    container_of((device), struct hd_struct, __dev)
-#define disk_to_dev(disk)      (&(disk)->part0.__dev)
 #define part_to_dev(part)      (&((part)->__dev))
 
+#define dev_to_disk(device)    (dev_to_part(device)->bdev->bd_disk)
+#define disk_to_dev(disk)      (part_to_dev((disk)->part0->bd_part))
+
 extern const struct device_type disk_type;
 extern struct device_type part_type;
 extern struct class block_class;
@@ -51,12 +52,9 @@ struct partition_meta_info {
 };
 
 struct hd_struct {
-       struct percpu_ref ref;
-
        struct block_device *bdev;
        struct device __dev;
        int partno;
-       struct rcu_work rcu_work;
 };
 
 /**
@@ -168,7 +166,7 @@ struct gendisk {
         * helpers.
         */
        struct disk_part_tbl __rcu *part_tbl;
-       struct hd_struct part0;
+       struct block_device *part0;
 
        const struct block_device_operations *fops;
        struct request_queue *queue;
@@ -278,7 +276,7 @@ extern void set_disk_ro(struct gendisk *disk, int flag);
 
 static inline int get_disk_ro(struct gendisk *disk)
 {
-       return disk->part0.bdev->bd_read_only;
+       return disk->part0->bd_read_only;
 }
 
 extern void disk_block_events(struct gendisk *disk);
@@ -302,7 +300,7 @@ static inline sector_t bdev_nr_sectors(struct block_device 
*bdev)
 
 static inline sector_t get_capacity(struct gendisk *disk)
 {
-       return bdev_nr_sectors(disk->part0.bdev);
+       return bdev_nr_sectors(disk->part0);
 }
 
 int bdev_disk_changed(struct block_device *bdev, bool invalidate);
diff --git a/include/linux/part_stat.h b/include/linux/part_stat.h
index 87ad60106e1db0..680de036691ef9 100644
--- a/include/linux/part_stat.h
+++ b/include/linux/part_stat.h
@@ -59,8 +59,8 @@ static inline void part_stat_set_all(struct hd_struct *part, 
int value)
 #define part_stat_add(part, field, addnd)      do {                    \
        __part_stat_add((part), field, addnd);                          \
        if ((part)->partno)                                             \
-               __part_stat_add(&part_to_disk((part))->part0,           \
-                               field, addnd);                          \
+               __part_stat_add(part_to_disk((part))->part0->bd_part,   \
+                       field, addnd); \
 } while (0)
 
 #define part_stat_dec(part, field)                                     \
-- 
2.29.2

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