715 	u32 *stack, *pre, *low, *dfs;  in bpf_compute_scc()  local
726 	 * - 'pre[t] == p' => preorder number of vertex 't' is 'p';  in bpf_compute_scc()
731 	pre = kvcalloc(insn_cnt, sizeof(int), GFP_KERNEL_ACCOUNT);  in bpf_compute_scc()
734 	if (!stack || !pre || !low || !dfs) {  in bpf_compute_scc()
744 	 * - suppose there is a path 'u' ~> 'v', such that 'pre[v] < pre[u]';  in bpf_compute_scc()
748 	 * - If 'low[v] < pre[v]', there is a path from 'v' to some vertex 'u',  in bpf_compute_scc()
749 	 *   such that 'pre[u] == low[v]'; vertex 'u' is currently on the stack,  in bpf_compute_scc()
751 	 * - If 'low[v] == pre[v]', loops containing 'v' have been explored,  in bpf_compute_scc()
757 	 *    pre = [0] * insn_cnt  in bpf_compute_scc()
769 	 *        pre[w] = next_preorder_num  in bpf_compute_scc()
776 	 *            # if pre[s] == 0:  in bpf_compute_scc()
780 	 *            #     low[w] = min(low[w], pre[s])  in bpf_compute_scc()
787 	 *            if pre[s] == 0:  in bpf_compute_scc()
794 	 *        if low[w] == pre[w]:  in bpf_compute_scc()
806 	 *        if pre[i] == 0:  in bpf_compute_scc()
812 		if (pre[i])  in bpf_compute_scc()
820 			if (pre[w] == 0) {  in bpf_compute_scc()
822 				pre[w] = next_preorder_num;  in bpf_compute_scc()
829 				if (pre[succ->items[j]]) {  in bpf_compute_scc()
840 			if (low[w] < pre[w]) {  in bpf_compute_scc()
879 	kvfree(pre);  in bpf_compute_scc()