Now that each hd_struct has a reference to the corresponding
block_device, there is no need for the bd_contains pointer. Add
a bdev_whole() helper to look up the whole device block_device
struture instead.
Signed-off-by: Christoph Hellwig <hch@xxxxxx>
---
drivers/scsi/scsicam.c | 2 +-
fs/block_dev.c | 46 ++++++++++++---------------------------
include/linux/blk_types.h | 4 +++-
3 files changed, 18 insertions(+), 34 deletions(-)
diff --git a/drivers/scsi/scsicam.c b/drivers/scsi/scsicam.c
index 682cf08ab04153..f1553a453616fd 100644
--- a/drivers/scsi/scsicam.c
+++ b/drivers/scsi/scsicam.c
@@ -32,7 +32,7 @@
*/
unsigned char *scsi_bios_ptable(struct block_device *dev)
{
- struct address_space *mapping = dev->bd_contains->bd_inode->i_mapping;
+ struct address_space *mapping = bdev_whole(dev)->bd_inode->i_mapping;
unsigned char *res = NULL;
struct page *page;
diff --git a/fs/block_dev.c b/fs/block_dev.c
index dd52dbd266cde7..258a1ced924483 100644
--- a/fs/block_dev.c
+++ b/fs/block_dev.c
@@ -879,7 +879,6 @@ struct block_device *bdev_alloc(struct gendisk *disk, u8 partno)
spin_lock_init(&bdev->bd_size_lock);
bdev->bd_disk = disk;
bdev->bd_partno = partno;
- bdev->bd_contains = NULL;
bdev->bd_super = NULL;
bdev->bd_inode = inode;
bdev->bd_part_count = 0;
@@ -1054,7 +1053,7 @@ static bool bd_may_claim(struct block_device *bdev, struct block_device *whole,
*/
int bd_prepare_to_claim(struct block_device *bdev, void *holder)
{
- struct block_device *whole = bdev->bd_contains;
+ struct block_device *whole = bdev_whole(bdev);
retry:
spin_lock(&bdev_lock);
@@ -1102,7 +1101,7 @@ static void bd_clear_claiming(struct block_device *whole, void *holder)
*/
static void bd_finish_claiming(struct block_device *bdev, void *holder)
{
- struct block_device *whole = bdev->bd_contains;
+ struct block_device *whole = bdev_whole(bdev);
spin_lock(&bdev_lock);
BUG_ON(!bd_may_claim(bdev, whole, holder));
@@ -1131,7 +1130,7 @@ static void bd_finish_claiming(struct block_device *bdev, void *holder)
void bd_abort_claiming(struct block_device *bdev, void *holder)
{
spin_lock(&bdev_lock);
- bd_clear_claiming(bdev->bd_contains, holder);
+ bd_clear_claiming(bdev_whole(bdev), holder);
spin_unlock(&bdev_lock);
}
EXPORT_SYMBOL(bd_abort_claiming);
@@ -1429,7 +1428,6 @@ static void put_disk_and_module(struct gendisk *disk)
static int __blkdev_get(struct block_device *bdev, fmode_t mode, void *holder,
int for_part)
{
- struct block_device *whole = NULL;
struct gendisk *disk = bdev->bd_disk;
int ret;
bool first_open = false, unblock_events = true, need_restart;
@@ -1447,26 +1445,17 @@ static int __blkdev_get(struct block_device *bdev, fmode_t mode, void *holder,
}
up_read(&disk->lookup_sem);
- if (bdev->bd_partno) {
- whole = bdget_disk(disk, 0);
- if (!whole) {
- ret = -ENOMEM;
- goto out_put_disk;
- }
- }
-
if (!for_part && (mode & FMODE_EXCL)) {
WARN_ON_ONCE(!holder);
ret = bd_prepare_to_claim(bdev, holder);
if (ret)
- goto out_put_whole;
+ goto out_put_disk;
}
disk_block_events(disk);
mutex_lock_nested(&bdev->bd_mutex, for_part);
if (!bdev->bd_openers) {
first_open = true;
- bdev->bd_contains = bdev;
if (!bdev->bd_partno) {
ret = -ENXIO;
@@ -1504,10 +1493,10 @@ static int __blkdev_get(struct block_device *bdev, fmode_t mode, void *holder,
goto out_clear;
} else {
BUG_ON(for_part);
- ret = __blkdev_get(whole, mode, NULL, 1);
+ ret = __blkdev_get(bdev_whole(bdev), mode, NULL, 1);
if (ret)
goto out_clear;
- bdev->bd_contains = bdgrab(whole);
+ bdgrab(bdev_whole(bdev));
bdev->bd_part = disk_get_part(disk, bdev->bd_partno);
if (!(disk->flags & GENHD_FL_UP) ||
!bdev->bd_part || !bdev->bd_part->nr_sects) {
@@ -1521,7 +1510,7 @@ static int __blkdev_get(struct block_device *bdev, fmode_t mode, void *holder,
if (bdev->bd_bdi == &noop_backing_dev_info)
bdev->bd_bdi = bdi_get(disk->queue->backing_dev_info);
} else {
- if (bdev->bd_contains == bdev) {
+ if (!bdev->bd_partno) {
ret = 0;
if (bdev->bd_disk->fops->open)
ret = bdev->bd_disk->fops->open(bdev, mode);
@@ -1560,24 +1549,18 @@ static int __blkdev_get(struct block_device *bdev, fmode_t mode, void *holder,
/* only one opener holds refs to the module and disk */
if (!first_open)
put_disk_and_module(disk);
- if (whole)
- bdput(whole);
return 0;
out_clear:
disk_put_part(bdev->bd_part);
bdev->bd_part = NULL;
- if (bdev != bdev->bd_contains)
- __blkdev_put(bdev->bd_contains, mode, 1);
- bdev->bd_contains = NULL;
+ if (bdev_is_partition(bdev))
+ __blkdev_put(bdev_whole(bdev), mode, 1);
out_unlock_bdev:
if (!for_part && (mode & FMODE_EXCL))
bd_abort_claiming(bdev, holder);
mutex_unlock(&bdev->bd_mutex);
disk_unblock_events(disk);
- out_put_whole:
- if (whole)
- bdput(whole);
out_put_disk:
put_disk_and_module(disk);
if (need_restart)
@@ -1768,8 +1751,7 @@ static void __blkdev_put(struct block_device *bdev, fmode_t mode, int for_part)
disk_put_part(bdev->bd_part);
bdev->bd_part = NULL;
if (bdev_is_partition(bdev))
- victim = bdev->bd_contains;
- bdev->bd_contains = NULL;
+ victim = bdev_whole(bdev);
put_disk_and_module(disk);
} else {
@@ -1787,6 +1769,7 @@ void blkdev_put(struct block_device *bdev, fmode_t mode)
mutex_lock(&bdev->bd_mutex);
if (mode & FMODE_EXCL) {
+ struct block_device *whole = bdev_whole(bdev);
bool bdev_free;
/*
@@ -1797,13 +1780,12 @@ void blkdev_put(struct block_device *bdev, fmode_t mode)
spin_lock(&bdev_lock);
WARN_ON_ONCE(--bdev->bd_holders < 0);
- WARN_ON_ONCE(--bdev->bd_contains->bd_holders < 0);
+ WARN_ON_ONCE(--whole->bd_holders < 0);
- /* bd_contains might point to self, check in a separate step */
if ((bdev_free = !bdev->bd_holders))
bdev->bd_holder = NULL;
- if (!bdev->bd_contains->bd_holders)
- bdev->bd_contains->bd_holder = NULL;
+ if (!whole->bd_holders)
+ whole->bd_holder = NULL;
spin_unlock(&bdev_lock);
diff --git a/include/linux/blk_types.h b/include/linux/blk_types.h
index 0069bee992063e..453b940b87d8e9 100644
--- a/include/linux/blk_types.h
+++ b/include/linux/blk_types.h
@@ -32,7 +32,6 @@ struct block_device {
#ifdef CONFIG_SYSFS
struct list_head bd_holder_disks;
#endif
- struct block_device * bd_contains;
u8 bd_partno;
struct hd_struct * bd_part;
/* number of times partitions within this device have been opened. */
@@ -48,6 +47,9 @@ struct block_device {
struct mutex bd_fsfreeze_mutex;
} __randomize_layout;
+#define bdev_whole(_bdev) \
+ ((_bdev)->bd_disk->part0.bdev)
+
#define bdev_kobj(_bdev) \
(&part_to_dev((_bdev)->bd_part)->kobj)
--
2.29.2
