Revert "nvidia-container-toolkit: wait for all device nodes to be present" (#463702)

      systemd.services.nvidia-container-toolkit-cdi-generator = {

        description = "Container Device Interface (CDI) for Nvidia generator";

        after = [ "systemd-udev-settle.service" ];

        requiredBy = lib.mkMerge [

          (lib.mkIf config.virtualisation.docker.enable [ "docker.service" ])

          (lib.mkIf config.virtualisation.podman.enable [ "podman.service" ])

        serviceConfig = {

          RuntimeDirectory = "cdi";

          RemainAfterExit = true;

          ExecStartPre = pkgs.writeShellScript "wait-for-nvidia-devices" ''

            set -eu

            gpus_dir="/proc/driver/nvidia/gpus"

            max_wait_seconds=60

            if [ ! -d "$gpus_dir" ]; then

              echo "wait-for-nvidia-devices: $gpus_dir does not exist; nothing to wait for."

              exit 0

            fi

            gpu_count=$(find "$gpus_dir" -mindepth 1 -maxdepth 1 -type d 2>/dev/null | wc -l | tr -d ' ')

            if [ "$gpu_count" -eq 0 ]; then

              echo "wait-for-nvidia-devices: no GPU entries found in $gpus_dir; nothing to wait for."

              exit 0

            fi

            echo "wait-for-nvidia-devices: expecting $gpu_count /dev/nvidiaN device node(s)."

            elapsed=0

            while true; do

              dev_count=$(find /dev -mindepth 1 -maxdepth 1 -type c -regex '.*/nvidia[0-9]+' 2>/dev/null | wc -l | tr -d ' ')

              if [ "$dev_count" -eq "$gpu_count" ]; then

                echo "wait-for-nvidia-devices: found $dev_count matching device node(s)."

                exit 0

              fi

              if [ "$elapsed" -ge "$max_wait_seconds" ]; then

                echo "wait-for-nvidia-devices: timed out after $max_wait_seconds seconds; expected $gpu_count node(s) but found $dev_count." >&2

                exit 1

              fi

              sleep 1

              elapsed=$((elapsed + 1))

            done

          '';

          ExecStart =

            let

              script = pkgs.callPackage ./cdi-generate.nix {