Hi! > commit 0ebcdd702f49aeb0ad2e2d894f8c124a0acc6e23 upstream. > > For a null_blk device with zoned mode enabled is currently initialized > with a number of zones equal to the device capacity divided by the zone > size, without considering if the device capacity is a multiple of the > zone size. If the zone size is not a divisor of the capacity, the zones > end up not covering the entire capacity, potentially resulting is out > of bounds accesses to the zone array. > > Fix this by adding one last smaller zone with a size equal to the > remainder of the disk capacity divided by the zone size if the capacity > is not a multiple of the zone size. For such smaller last zone, the zone > capacity is also checked so that it does not exceed the smaller zone > size. > --- a/drivers/block/null_blk_zoned.c > +++ b/drivers/block/null_blk_zoned.c > @@ -1,9 +1,9 @@ > // SPDX-License-Identifier: GPL-2.0 > #include <linux/vmalloc.h> > +#include <linux/sizes.h> > #include "null_blk.h" > > -/* zone_size in MBs to sectors. */ > -#define ZONE_SIZE_SHIFT 11 > +#define MB_TO_SECTS(mb) (((sector_t)mb * SZ_1M) >> SECTOR_SHIFT) This macro is quite dangerous. (mb) would help, but inline function would be better. > + dev->nr_zones = dev_capacity_sects >> ilog2(dev->zone_size_sects); > + if (dev_capacity_sects & (dev->zone_size_sects - 1)) > + dev->nr_zones++; Is this same as nr_zones = DIV_ROUND_UP(dev_capacity_sects, dev->zone_size_sects)? Would that be faster, more readable and robust against weird dev->zone_size_sects sizes? Best regards, Pavel -- http://www.livejournal.com/~pavelmachek
Attachment:
signature.asc
Description: PGP signature
