[PATCH 06/10] dasd: use blk_drop_partitions instead of badly reimplementing it

Christoph Hellwig
2020-04-14T07:29:25Z

Use the blk_drop_partitions function instead of messing around with
ioctls that get kernel pointers. For this blk_drop_partitions needs
to be exported, which it normally shouldn't - make an exception for
s390 only.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
block/partitions/core.c | 4 ++++
drivers/s390/block/dasd_genhd.c | 20 ++++----------------
2 files changed, 8 insertions(+), 16 deletions(-)

diff --git a/block/partitions/core.c b/block/partitions/core.c
index deccc3fbcd37..8c5295ca8ea6 100644
--- a/block/partitions/core.c
+++ b/block/partitions/core.c
@@ -624,6 +624,10 @@ int blk_drop_partitions(struct block_device *bdev)

return 0;
}
+#ifdef CONFIG_S390
+/* for historic reasons in the DASD driver */
+EXPORT_SYMBOL_GPL(blk_drop_partitions);
+#endif

static bool blk_add_partition(struct gendisk *disk, struct block_device *bdev,
struct parsed_partitions *state, int p)
diff --git a/drivers/s390/block/dasd_genhd.c b/drivers/s390/block/dasd_genhd.c
index 7d079154f849..af5b0ecb8f89 100644
--- a/drivers/s390/block/dasd_genhd.c
+++ b/drivers/s390/block/dasd_genhd.c
@@ -143,9 +143,6 @@ int dasd_scan_partitions(struct dasd_block *block)
*/
void dasd_destroy_partitions(struct dasd_block *block)
{
- /* The two structs have 168/176 byte on 31/64 bit. */
- struct blkpg_partition bpart;
- struct blkpg_ioctl_arg barg;
struct block_device *bdev;

/*
@@ -155,19 +152,10 @@ void dasd_destroy_partitions(struct dasd_block *block)
bdev = block->bdev;
block->bdev = NULL;

- /*
- * See fs/partition/check.c:delete_partition
- * Can't call delete_partitions directly. Use ioctl.
- * The ioctl also does locking and invalidation.
- */
- memset(&bpart, 0, sizeof(struct blkpg_partition));
- memset(&barg, 0, sizeof(struct blkpg_ioctl_arg));
- barg.data = (void __force __user *) &bpart;
- barg.op = BLKPG_DEL_PARTITION;
- for (bpart.pno = block->gdp->minors - 1; bpart.pno > 0; bpart.pno--)
- ioctl_by_bdev(bdev, BLKPG, (unsigned long) &barg);
-
- invalidate_partition(block->gdp, 0);
+ mutex_lock(&bdev->bd_mutex);
+ blk_drop_partitions(bdev);
+ mutex_unlock(&bdev->bd_mutex);
+
/* Matching blkdev_put to the blkdev_get in dasd_scan_partitions. */
blkdev_put(bdev, FMODE_READ);
set_capacity(block->gdp, 0);
--
2.25.1