write_seqcount_latch_begin
write_seqcount_latch_begin(&c2n->seq);
write_seqcount_latch_begin(&root->seq);
write_seqcount_latch_begin(&root->seq);
write_seqcount_latch_begin(&ls->latch);
write_seqcount_latch_begin(&cd.seq);
write_seqcount_latch_begin(&tkf->seq);