block: Limit allocation of zone descriptors for report zones

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.

Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/block/blk-zoned.c b/block/blk-zoned.c
index 32e377f..bb4ed69 100644 (file)
--- 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);