Dan Carpenter found a possible divide by 0 issue in the smartpqi driver in functions pci_get_aio_common_raid_map_values and pqi_calc_aio_r5_or_r6. The variable rmd->blocks_per_row is used as a divisor and could be 0. Link: https://lore.kernel.org/linux-scsi/YG%2F5kWHHAr7w5dU5@mwanda/ Fixes: 6702d2c40f31 ("scsi: smartpqi: Add support for RAID5 and RAID6 writes") Using rmd->blocks_per_row as a divisor without checking it for 0 first. Correct these possible divide by 0 conditions by insuring that rmd->blocks_per_row is not zero before usage. The check for non-0 was too late to prevent a divide by 0 condition. Add in a comment to explain why the check for non-zero is necessary. If the member is 0, return PQI_RAID_BYPASS_INELIGIBLE before any division is performed. Reported-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx> Reported-by: kernel test robot <lkp@xxxxxxxxx> Reviewed-by: Scott Benesh <scott.benesh@xxxxxxxxxxxxx> Reviewed-by: Scott Teel <scott.teel@xxxxxxxxxxxxx> Reviewed-by: Mike McGowen <mike.mcgowen@xxxxxxxxxxxxx> Reviewed-by: Kevin Barnett <kevin.barnett@xxxxxxxxxxxxx> Signed-off-by: Don Brace <don.brace@xxxxxxxxxxxxx> --- drivers/scsi/smartpqi/smartpqi_init.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/drivers/scsi/smartpqi/smartpqi_init.c b/drivers/scsi/smartpqi/smartpqi_init.c index 3b0f281daa2b..797ac699b7ff 100644 --- a/drivers/scsi/smartpqi/smartpqi_init.c +++ b/drivers/scsi/smartpqi/smartpqi_init.c @@ -2510,6 +2510,8 @@ static int pci_get_aio_common_raid_map_values(struct pqi_ctrl_info *ctrl_info, /* Calculate stripe information for the request. */ rmd->blocks_per_row = rmd->data_disks_per_row * rmd->strip_size; + if (rmd->blocks_per_row == 0) /* Used as a divisor in many calculations */ + return PQI_RAID_BYPASS_INELIGIBLE; #if BITS_PER_LONG == 32 tmpdiv = rmd->first_block; do_div(tmpdiv, rmd->blocks_per_row); @@ -2559,6 +2561,10 @@ static int pqi_calc_aio_r5_or_r6(struct pqi_scsi_dev_raid_map_data *rmd, #if BITS_PER_LONG == 32 u64 tmpdiv; #endif + + if (rmd->blocks_per_row == 0) /* Used as a divisor in many calculations */ + return PQI_RAID_BYPASS_INELIGIBLE; + /* RAID 50/60 */ /* Verify first and last block are in same RAID group. */ rmd->stripesize = rmd->blocks_per_row * rmd->layout_map_count; @@ -2662,8 +2668,6 @@ static int pqi_calc_aio_r5_or_r6(struct pqi_scsi_dev_raid_map_data *rmd, rmd->q_parity_it_nexus = raid_map->disk_data[index + 1].aio_handle; rmd->xor_mult = raid_map->disk_data[rmd->map_index].xor_mult[1]; } - if (rmd->blocks_per_row == 0) - return PQI_RAID_BYPASS_INELIGIBLE; #if BITS_PER_LONG == 32 tmpdiv = rmd->first_block; do_div(tmpdiv, rmd->blocks_per_row);
