Re: [PATCH net-next] liquidio: fix kernel panic when NIC firmware is older than 1.7.2

[Shannon Nelson <shannon.nelson@oracle.com>]

On 6/26/2018 4:58 AM, Felix Manlunas wrote:
> From: Rick Farrington <ricardo.farrington@cavium.com>
> 
> Pre-1.7.2 NIC firmware does not support (and does not respond to) the "get
> speed" command which is sent by the 1.7.2 driver during modprobe.  Due to a
> bug in older firmware (with respect to unknown commands), this unsupported
> command causes a cascade of errors that ends in a kernel panic.
> 
> Fix it by making the sending of the "get speed" command conditional on the
> firmware version.
> 
> Signed-off-by: Rick Farrington <ricardo.farrington@cavium.com>
> Acked-by: Derek Chickles <derek.chickles@cavium.com>
> Signed-off-by: Felix Manlunas <felix.manlunas@cavium.com>
> ---
> Note: To avoid checkpatch.pl "WARNING: line over 80 characters", the comma
>        that separates the arguments in the call to strcmp() was placed one
>        line below the usual spot.
> 
>   drivers/net/ethernet/cavium/liquidio/lio_main.c | 11 ++++++++++-
>   1 file changed, 10 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/net/ethernet/cavium/liquidio/lio_main.c b/drivers/net/ethernet/cavium/liquidio/lio_main.c
> index 7cb4e75..f83f884 100644
> --- a/drivers/net/ethernet/cavium/liquidio/lio_main.c
> +++ b/drivers/net/ethernet/cavium/liquidio/lio_main.c
> @@ -3671,7 +3671,16 @@ static int setup_nic_devices(struct octeon_device *octeon_dev)
>   			OCTEON_CN2350_25GB_SUBSYS_ID ||
>   		    octeon_dev->subsystem_id ==
>   			OCTEON_CN2360_25GB_SUBSYS_ID) {
> -			liquidio_get_speed(lio);
> +			/* speed control unsupported in f/w older than 1.7.2 */
> +			if (strcmp(octeon_dev->fw_info.liquidio_firmware_version
> +			   , "1.7.2") < 0) {

Will the liquidio_firmware_version ever end up something like 1.7.10? 
If so, this strcmp() may not do what you want.

sln

> +				dev_info(&octeon_dev->pci_dev->dev,
> +					 "speed setting not supported by f/w.");
> +				octeon_dev->speed_setting = 25;
> +				octeon_dev->no_speed_setting = 1;
> +			} else {
> +				liquidio_get_speed(lio);
> +			}
>   
>   			if (octeon_dev->speed_setting == 0) {
>   				octeon_dev->speed_setting = 25;
>