The max_part may overflow. For example,
modprobe brd rd_nr=3 rd_size=102400 max_part=1073741824(2^30)
Expected result
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
ram0 1:0 0 100M 0 disk
ram1 1:256 0 100M 0 disk
ram2 1:512 0 100M 0 disk
Actual result
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
ram0 259:0 0 100M 0 disk
ram1 259:1 0 100M 0 disk
ram2 259:2 0 100M 0 disk
Fix it.
Signed-off-by: Lixiaokeng <lixiaokeng@xxxxxxxxxx>
Signed-off-by: Zhiqiang Liu <liuzhiqiang26@xxxxxxxxxx>
---
drivers/block/brd.c | 8 +++-----
1 file changed, 3 insertions(+), 5 deletions(-)
diff --git a/drivers/block/brd.c b/drivers/block/brd.c
index c43a6ab4b1f3..c91831cd5d2a 100644
--- a/drivers/block/brd.c
+++ b/drivers/block/brd.c
@@ -457,21 +457,19 @@ static void brd_del_one(struct brd_device *brd)
static inline void brd_check_and_reset_par(void)
{
- if (unlikely(!max_part))
+ if (unlikely(max_part <= 0))
max_part = 1;
/*
* make sure 'max_part' can be divided exactly by (1U << MINORBITS),
* otherwise, it is possiable to get same dev_t when adding partitions.
*/
- if ((1U << MINORBITS) % max_part != 0)
- max_part = 1UL << fls(max_part);
-
if (max_part > DISK_MAX_PARTS) {
pr_info("brd: max_part can't be larger than %d, reset max_part = %d.\n",
DISK_MAX_PARTS, DISK_MAX_PARTS);
max_part = DISK_MAX_PARTS;
- }
+ } else if ((1U << MINORBITS) % max_part != 0)
+ max_part = 1UL << fls(max_part);
}
static int __init brd_init(void)
--
