SLF_KEEPTEST
if (test_bit(SLF_KEEPTEST, &sl->flags))
clear_bit(SLF_KEEPTEST, &sl->flags);
set_bit(SLF_KEEPTEST, &sl->flags);
set_bit(SLF_KEEPTEST, &sl->flags);
if (test_bit(SLF_KEEPTEST, &sl->flags)) {
set_bit(SLF_KEEPTEST, &sl->flags);
if (test_bit(SLF_KEEPTEST, &sl->flags))
clear_bit(SLF_KEEPTEST, &sl->flags);