diff options
Diffstat (limited to 'drivers/block/brd.c')
| -rw-r--r-- | drivers/block/brd.c | 22 |
1 files changed, 20 insertions, 2 deletions
diff --git a/drivers/block/brd.c b/drivers/block/brd.c index 0c76d4016eeb..7e35574a17df 100644 --- a/drivers/block/brd.c +++ b/drivers/block/brd.c @@ -581,6 +581,25 @@ static struct kobject *brd_probe(dev_t dev, int *part, void *data) return kobj; } +static inline void brd_check_and_reset_par(void) +{ + if (unlikely(!max_part)) + 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; + } +} + static int __init brd_init(void) { struct brd_device *brd, *next; @@ -604,8 +623,7 @@ static int __init brd_init(void) if (register_blkdev(RAMDISK_MAJOR, "ramdisk")) return -EIO; - if (unlikely(!max_part)) - max_part = 1; + brd_check_and_reset_par(); for (i = 0; i < rd_nr; i++) { brd = brd_alloc(i); |