Subject: Re: [patch net-next 5/6] selftests: forwarding: add wait_for_dev() helper

From: Benjamin Poirier <[email-masked]>
Date: Fri, 12 Apr 2024 16:43:40 -0400

On 2024-04-12 17:13 +0200, Jiri Pirko wrote:
> From: Jiri Pirko <[email-masked]>
> 
> The existing setup_wait*() helper family check the status of the
> interface to be up. Introduce wait_for_dev() to wait for the netdevice
> to appear, for example after test script does manual device bind.
> 
> Signed-off-by: Jiri Pirko <[email-masked]>
> ---
>  tools/testing/selftests/net/forwarding/lib.sh | 19 +++++++++++++++++++
>  1 file changed, 19 insertions(+)
> 
> diff --git a/tools/testing/selftests/net/forwarding/lib.sh b/tools/testing/selftests/net/forwarding/lib.sh
> index 959183b516ce..74859f969997 100644
> --- a/tools/testing/selftests/net/forwarding/lib.sh
> +++ b/tools/testing/selftests/net/forwarding/lib.sh
> @@ -746,6 +746,25 @@ setup_wait()
>  	sleep $WAIT_TIME
>  }
>  
> +wait_for_dev()
> +{
> +	local dev=$1; shift
> +	local timeout=${1:-$WAIT_TIMEOUT}; shift
> +	local max_iterations=$(($timeout * 10))
> +
> +	for ((i = 1; i <= $max_iterations; ++i)); do
> +		ip link show dev $dev up &> /dev/null
> +		if [[ $? -ne 0 ]]; then
> +			sleep 0.1
> +		else
> +			return 0
> +		fi
> +	done
> +
> +	log_test wait_for_dev ": Interface $dev did not appear."
> +	exit 1
> +}

How about rewriting the function to make use of the `slowwait` helper as
follows:

wait_for_dev()
{
	local dev=$1; shift
	local timeout=${1:-$WAIT_TIMEOUT}; shift

	slowwait $timeout ip link show dev $dev up &> /dev/null
	if (( $? )); then
		check_err 1
		log_test wait_for_dev "Interface $dev did not appear."
		exit $EXIT_STATUS
	fi
}