bpf: Define cgroup_bpf_enabled for CONFIG_CGROUP_BPF=n

rdna · borkmann · commit 13193b0f392f · 2018-05-28T17:41:01.000+02:00
Static key is used to enable/disable cgroup-bpf related code paths at
run time.

Though it's not defined when cgroup-bpf is disabled at compile time,
i.e. CONFIG_CGROUP_BPF=n, and if some code wants to use it, it has to do
this:

	#ifdef CONFIG_CGROUP_BPF
		if (cgroup_bpf_enabled) {
			/* ... some work ... */
		}
	#endif

This code can be simplified by setting cgroup_bpf_enabled to 0 for
CONFIG_CGROUP_BPF=n case:

	if (cgroup_bpf_enabled) {
		/* ... some work ... */
	}

And it aligns well with existing BPF_CGROUP_RUN_PROG_* macros that
defined for both states of CONFIG_CGROUP_BPF.

Signed-off-by: Andrey Ignatov &lt;rdna@fb.com&gt;
Acked-by: Alexei Starovoitov &lt;ast@kernel.org&gt;
Signed-off-by: Daniel Borkmann &lt;daniel@iogearbox.net&gt;
diff --git a/include/linux/bpf-cgroup.h b/include/linux/bpf-cgroup.h
@@ -185,6 +185,7 @@ struct cgroup_bpf {};
 static inline void cgroup_bpf_put(struct cgroup *cgrp) {}
 static inline int cgroup_bpf_inherit(struct cgroup *cgrp) { return 0; }
 
+#define cgroup_bpf_enabled (0)
 #define BPF_CGROUP_PRE_CONNECT_ENABLED(sk) (0)
 #define BPF_CGROUP_RUN_PROG_INET_INGRESS(sk,skb) ({ 0; })
 #define BPF_CGROUP_RUN_PROG_INET_EGRESS(sk,skb) ({ 0; })
