open my $fh, "<", $csv_filename or die "Cannot open file \"$csv_filename\": $!\n";

while (my $row = $csv->getline ($fh)) {
    $d_array[++$line_number] = $row;
    # or even nicer
    # push @d_array, $row;
    }
$csv->eof or $csv->error_diag ();
close $fh or die "Cannot open file \"$csv_filename\": $!\n";