[PATCH 8/9] block: remove DISK_PITER_REVERSE

Christoph Hellwig
2020-12-01T16:56:15Z

There is good reason to iterate backwards when deleting all partitions in
del_gendisk, just like we don't in blk_drop_partitions.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
block/genhd.c | 34 ++++------------------------------
include/linux/genhd.h | 1 -
2 files changed, 4 insertions(+), 31 deletions(-)

diff --git a/block/genhd.c b/block/genhd.c
index 65dba32df5474f..7730ddabebba92 100644
--- a/block/genhd.c
+++ b/block/genhd.c
@@ -182,24 +182,13 @@ static struct block_device *__disk_get_part(struct gendisk *disk, int partno)
void disk_part_iter_init(struct disk_part_iter *piter, struct gendisk *disk,
unsigned int flags)
{
- struct disk_part_tbl *ptbl;
-
- rcu_read_lock();
- ptbl = rcu_dereference(disk->part_tbl);
-
piter->disk = disk;
piter->part = NULL;
-
- if (flags & DISK_PITER_REVERSE)
- piter->idx = ptbl->len - 1;
- else if (flags & (DISK_PITER_INCL_PART0 | DISK_PITER_INCL_EMPTY_PART0))
+ if (flags & (DISK_PITER_INCL_PART0 | DISK_PITER_INCL_EMPTY_PART0))
piter->idx = 0;
else
piter->idx = 1;
-
piter->flags = flags;
-
- rcu_read_unlock();
}

/**
@@ -214,7 +203,6 @@ void disk_part_iter_init(struct disk_part_iter *piter, struct gendisk *disk,
struct block_device *disk_part_iter_next(struct disk_part_iter *piter)
{
struct disk_part_tbl *ptbl;
- int inc, end;

/* put the last partition */
disk_part_iter_exit(piter);
@@ -223,21 +211,8 @@ struct block_device *disk_part_iter_next(struct disk_part_iter *piter)
rcu_read_lock();
ptbl = rcu_dereference(piter->disk->part_tbl);

- /* determine iteration parameters */
- if (piter->flags & DISK_PITER_REVERSE) {
- inc = -1;
- if (piter->flags & (DISK_PITER_INCL_PART0 |
- DISK_PITER_INCL_EMPTY_PART0))
- end = -1;
- else
- end = 0;
- } else {
- inc = 1;
- end = ptbl->len;
- }
-
/* iterate to the next partition */
- for (; piter->idx != end; piter->idx += inc) {
+ for (; piter->idx != ptbl->len; piter->idx += 1) {
struct block_device *part;

part = rcu_dereference(ptbl->part[piter->idx]);
@@ -252,7 +227,7 @@ struct block_device *disk_part_iter_next(struct disk_part_iter *piter)
piter->part = bdgrab(part);
if (!piter->part)
continue;
- piter->idx += inc;
+ piter->idx += 1;
break;
}

@@ -776,8 +751,7 @@ void del_gendisk(struct gendisk *disk)
down_write(&bdev_lookup_sem);

/* invalidate stuff */
- disk_part_iter_init(&piter, disk,
- DISK_PITER_INCL_EMPTY | DISK_PITER_REVERSE);
+ disk_part_iter_init(&piter, disk, DISK_PITER_INCL_EMPTY);
while ((part = disk_part_iter_next(&piter))) {
invalidate_partition(part);
delete_partition(part);
diff --git a/include/linux/genhd.h b/include/linux/genhd.h
index 191f5e4ae4e93b..425956ac9315fa 100644
--- a/include/linux/genhd.h
+++ b/include/linux/genhd.h
@@ -217,7 +217,6 @@ void disk_uevent(struct gendisk *disk, enum kobject_action action);
/*
* Smarter partition iterator without context limits.
*/
-#define DISK_PITER_REVERSE (1 << 0) /* iterate in the reverse direction */
#define DISK_PITER_INCL_EMPTY (1 << 1) /* include 0-sized parts */
#define DISK_PITER_INCL_PART0 (1 << 2) /* include partition 0 */
#define DISK_PITER_INCL_EMPTY_PART0 (1 << 3) /* include empty partition 0 */
--
2.29.2