On Wed, Aug 12, 2020 at 10:32:49AM +0100, Edward Cree wrote:
> The handling of the RXQ/TXQ size granularity design-params had two
> problems: it had a 64-bit divide that didn't build on 32-bit platforms,
> and it could divide by zero if the NIC supplied 0 as the value of the
> design-param. Fix both by checking for 0 and for a granularity bigger
> than our min-size; if the granularity <= EFX_MIN_DMAQ_SIZE then it fits
> in 32 bits, so we can cast it to u32 for the divide.
>
> Reported-by: kernel test robot <l...@intel.com>
> Signed-off-by: Edward Cree <ec...@solarflare.com>
Reviewed-by: Guenter Roeck <li...@roeck-us.net>
> ---
> I've only build-tested this, and then only on 64-bit, since our lab's
> cooling system can't cope with the heatwave and we keep having to shut
> everything down :(
>
> drivers/net/ethernet/sfc/ef100_nic.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/net/ethernet/sfc/ef100_nic.c
> b/drivers/net/ethernet/sfc/ef100_nic.c
> index 36598d0542ed..206d70f9d95b 100644
> --- a/drivers/net/ethernet/sfc/ef100_nic.c
> +++ b/drivers/net/ethernet/sfc/ef100_nic.c
> @@ -979,7 +979,8 @@ static int ef100_process_design_param(struct efx_nic *efx,
> * EFX_MIN_DMAQ_SIZE is divisible by GRANULARITY.
> * This is very unlikely to fail.
> */
> - if (EFX_MIN_DMAQ_SIZE % reader->value) {
> + if (!reader->value || reader->value > EFX_MIN_DMAQ_SIZE ||
> + EFX_MIN_DMAQ_SIZE % (u32)reader->value) {
> netif_err(efx, probe, efx->net_dev,
> "%s size granularity is %llu, can't guarantee
> safety\n",
> reader->type ==
> ESE_EF100_DP_GZ_RXQ_SIZE_GRANULARITY ? "RXQ" : "TXQ",
