block: Fix potential overflow in blk_report_zones()

For large values of the number of zones reported and/or large zone
sizes, the sector increment calculated with

blk_queue_zone_sectors(q) * n

in blk_report_zones() loop can overflow the unsigned int type used for
the calculation as both "n" and blk_queue_zone_sectors() value are
unsigned int. E.g. for a device with 256 MB zones (524288 sectors),
overflow happens with 8192 or more zones reported.

Changing the return type of blk_queue_zone_sectors() to sector_t, fixes
this problem and avoids overflow problem for all other callers of this
helper too. The same change is also applied to the bdev_zone_sectors()
helper.

Fixes: e76239a3748c ("block: add a report_zones method")
Cc: stable@vger.kernel.org
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 ae7e91bd06187c6b410f81370b00a8ac9c21cd68..3249738242b4c2be4cf2b396f4666654d6776f94 100644 (file)
--- a/block/blk-zoned.c
+++ b/block/blk-zoned.c
@@ -70,7 +70,7 @@ EXPORT_SYMBOL_GPL(__blk_req_zone_write_unlock);
 static inline unsigned int __blkdev_nr_zones(struct request_queue *q,
                                             sector_t nr_sectors)
 {
-       unsigned long zone_sectors = blk_queue_zone_sectors(q);
+       sector_t zone_sectors = blk_queue_zone_sectors(q);
 
        return (nr_sectors + zone_sectors - 1) >> ilog2(zone_sectors);
 }

diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 0c482371c8b38212714f09792a5d166c8a7be365..259bd7ad8312ed8b26bf2447fc7e7270d2fdcd0c 100644 (file)
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -681,7 +681,7 @@ static inline bool blk_queue_is_zoned(struct request_queue *q)
        }
 }
 
-static inline unsigned int blk_queue_zone_sectors(struct request_queue *q)
+static inline sector_t blk_queue_zone_sectors(struct request_queue *q)
 {
        return blk_queue_is_zoned(q) ? q->limits.chunk_sectors : 0;
 }
@@ -1418,7 +1418,7 @@ static inline bool bdev_is_zoned(struct block_device *bdev)
        return false;
 }
 
-static inline unsigned int bdev_zone_sectors(struct block_device *bdev)
+static inline sector_t bdev_zone_sectors(struct block_device *bdev)
 {
        struct request_queue *q = bdev_get_queue(bdev);