Subject: Re: [PATCH net 2/3] selftests: net: lib: avoid error removing empty netns name

From: Petr Machata <[email-masked]>
Date: Wed, 5 Jun 2024 12:38:27 +0200

"Matthieu Baerts (NGI0)" <[email-masked]> writes:

> If there is an error to create the first netns with 'setup_ns()',
> 'cleanup_ns()' will be called with an empty string as first parameter.
>
> The consequences is that 'cleanup_ns()' will try to delete an invalid
> netns, and wait 20 seconds if the netns list is empty.
>
> Instead of just checking if the name is not empty, convert the string
> separated by spaces to an array. Manipulating the array is cleaner, and
> calling 'cleanup_ns()' with an empty array will be a no-op.
>
> Fixes: 25ae948b4478 ("selftests/net: add lib.sh")
> Cc: [email-masked]
> Acked-by: Geliang Tang <[email-masked]>
> Signed-off-by: Matthieu Baerts (NGI0) <[email-masked]>
> ---
>  tools/testing/selftests/net/lib.sh | 13 +++++++------
>  1 file changed, 7 insertions(+), 6 deletions(-)
>
> diff --git a/tools/testing/selftests/net/lib.sh b/tools/testing/selftests/net/lib.sh
> index a422e10d3d3a..e2f51102d7e1 100644
> --- a/tools/testing/selftests/net/lib.sh
> +++ b/tools/testing/selftests/net/lib.sh
> @@ -15,7 +15,7 @@ ksft_xfail=2
>  ksft_skip=4
>  
>  # namespace list created by setup_ns
> -NS_LIST=""
> +NS_LIST=()
>  
>  ##############################################################################
>  # Helpers
> @@ -137,6 +137,7 @@ cleanup_ns()
>  	fi
>  
>  	for ns in "$@"; do
> +		[ -z "${ns}" ] && continue

I think this is now irrelevant though? Now cleanup_ns() will be called
with no arguments for an empty NS list, so the loop does not even kick in.

>  		ip netns delete "${ns}" &> /dev/null
>  		if ! busywait $BUSYWAIT_TIMEOUT ip netns list \| grep -vq "^$ns$" &> /dev/null; then
>  			echo "Warn: Failed to remove namespace $ns"
> @@ -150,7 +151,7 @@ cleanup_ns()
>  
>  cleanup_all_ns()
>  {
> -	cleanup_ns $NS_LIST
> +	cleanup_ns "${NS_LIST[@]}"
>  }
>  
>  # setup netns with given names as prefix. e.g
> @@ -159,7 +160,7 @@ setup_ns()
>  {
>  	local ns=""
>  	local ns_name=""
> -	local ns_list=""
> +	local ns_list=()
>  	local ns_exist=
>  	for ns_name in "$@"; do
>  		# Some test may setup/remove same netns multi times
> @@ -175,13 +176,13 @@ setup_ns()
>  
>  		if ! ip netns add "$ns"; then
>  			echo "Failed to create namespace $ns_name"
> -			cleanup_ns "$ns_list"
> +			cleanup_ns "${ns_list[@]}"
>  			return $ksft_skip
>  		fi
>  		ip -n "$ns" link set lo up
> -		! $ns_exist && ns_list="$ns_list $ns"
> +		! $ns_exist && ns_list+=("$ns")
>  	done
> -	NS_LIST="$NS_LIST $ns_list"
> +	NS_LIST+=("${ns_list[@]}")
>  }
>  
>  tc_rule_stats_get()