[PATCH v2 05/11] block: Limit allocation of zone descriptors for report zones

Damien Le Moal
2018-10-11T07:09:46Z

There is no point in allocating more zone descriptors than the number of
zones a block device has for doing a zone report. Avoid doing that in
blkdev_report_zones_ioctl() by limiting the number of zone decriptors
allocated internally to process the user request.

Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
---
block/blk-zoned.c | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/block/blk-zoned.c b/block/blk-zoned.c
index 32e377f755d8..bb4ed69f917f 100644
--- a/block/blk-zoned.c
+++ b/block/blk-zoned.c
@@ -355,8 +355,7 @@ int blkdev_report_zones_ioctl(struct block_device *bdev, fmode_t mode,
if (!rep.nr_zones)
return -EINVAL;

- if (rep.nr_zones > INT_MAX / sizeof(struct blk_zone))
- return -ERANGE;
+ rep.nr_zones = min(blkdev_nr_zones(bdev), rep.nr_zones);

zones = kvmalloc_array(rep.nr_zones, sizeof(struct blk_zone),
GFP_KERNEL | __GFP_ZERO);
--
2.17.1