Re: [PATCH net-next v7 10/12] selftests: ncdevmem: Run selftest when none of the -s or -c has been provided

[Joe Damato <jdamato@fastly.com>]

On Mon, Nov 04, 2024 at 10:14:28AM -0800, Stanislav Fomichev wrote:
> This will be used as a 'probe' mode in the selftest to check whether
> the device supports the devmem or not. Use hard-coded queue layout
> (two last queues) and prevent user from passing custom -q and/or -t.
> 
> Reviewed-by: Mina Almasry <almasrymina@google.com>
> Signed-off-by: Stanislav Fomichev <sdf@fomichev.me>
> ---
>  tools/testing/selftests/net/ncdevmem.c | 42 ++++++++++++++++++++------
>  1 file changed, 32 insertions(+), 10 deletions(-)
> 
> diff --git a/tools/testing/selftests/net/ncdevmem.c b/tools/testing/selftests/net/ncdevmem.c
> index 044198ce02a7..270a77206f65 100644
> --- a/tools/testing/selftests/net/ncdevmem.c
> +++ b/tools/testing/selftests/net/ncdevmem.c
> @@ -76,7 +76,7 @@ static char *client_ip;
>  static char *port;
>  static size_t do_validation;
>  static int start_queue = -1;
> -static int num_queues = 1;
> +static int num_queues = -1;
>  static char *ifname;
>  static unsigned int ifindex;
>  static unsigned int dmabuf_id;
> @@ -731,19 +731,31 @@ int main(int argc, char *argv[])
>  		}
>  	}
>  
> -	if (!server_ip)
> -		error(1, 0, "Missing -s argument\n");
> -
> -	if (!port)
> -		error(1, 0, "Missing -p argument\n");
> -
>  	if (!ifname)
>  		error(1, 0, "Missing -f argument\n");
>  
>  	ifindex = if_nametoindex(ifname);
>  
> -	if (start_queue < 0) {
> -		start_queue = rxq_num(ifindex) - 1;
> +	if (!server_ip && !client_ip) {
> +		if (start_queue < 0 && num_queues < 0) {
> +			num_queues = rxq_num(ifindex);
> +			if (num_queues < 0)
> +				error(1, 0, "couldn't detect number of queues\n");
> +			/* make sure can bind to multiple queues */
> +			start_queue = num_queues / 2;
> +			num_queues /= 2;

Sorry for the beginner question :) -- is it possible that rxq_num
ever returns 1 and thus start_queue = 0, num_queues = 0

> +		}
> +
> +		if (start_queue < 0 || num_queues < 0)
> +			error(1, 0, "Both -t and -q are required\n");

And then isn't caught here because this only checks < 0 (instead of
num_queues <= 0) ?