[PATCH 4.14 013/115] s390/dasd: Fix capacity calculation for large volumes

Greg Kroah-Hartman
2019-05-15T11:17:59Z

[ Upstream commit 2cc9637ce825f3a9f51f8f78af7474e9e85bfa5f ]

The DASD driver incorrectly limits the maximum number of blocks of ECKD
DASD volumes to 32 bit numbers. Volumes with a capacity greater than
2^32-1 blocks are incorrectly recognized as smaller volumes.

This results in the following volume capacity limits depending on the
formatted block size:

BLKSIZE MAX_GB MAX_CYL
512 2047 5843492
1024 4095 8676701
2048 8191 13634816
4096 16383 23860929

The same problem occurs when a volume with more than 17895697 cylinders
is accessed in raw-track-access mode.

Fix this problem by adding an explicit type cast when calculating the
maximum number of blocks.

Signed-off-by: Peter Oberparleiter <oberpar@linux.ibm.com>
Reviewed-by: Stefan Haberland <sth@linux.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/s390/block/dasd_eckd.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/s390/block/dasd_eckd.c b/drivers/s390/block/dasd_eckd.c
index 0a1e7f9b5239d..0d5e2d92e05bc 100644
--- a/drivers/s390/block/dasd_eckd.c
+++ b/drivers/s390/block/dasd_eckd.c
@@ -2001,14 +2001,14 @@ static int dasd_eckd_end_analysis(struct dasd_block *block)
blk_per_trk = recs_per_track(&private->rdc_data, 0, block->bp_block);

raw:
- block->blocks = (private->real_cyl *
+ block->blocks = ((unsigned long) private->real_cyl *
private->rdc_data.trk_per_cyl *
blk_per_trk);

dev_info(&device->cdev->dev,
- "DASD with %d KB/block, %d KB total size, %d KB/track, "
+ "DASD with %u KB/block, %lu KB total size, %u KB/track, "
"%s\n", (block->bp_block >> 10),
- ((private->real_cyl *
+ (((unsigned long) private->real_cyl *
private->rdc_data.trk_per_cyl *
blk_per_trk * (block->bp_block >> 9)) >> 1),
((blk_per_trk * block->bp_block) >> 10),
--
2.20.1