net: filter: split 'struct sk_filter' into socket and bpf parts

clean up names related to socket filtering and bpf in the following way:
- everything that deals with sockets keeps 'sk_*' prefix
- everything that is pure BPF is changed to 'bpf_*' prefix

split 'struct sk_filter' into
struct sk_filter {
	atomic_t        refcnt;
	struct rcu_head rcu;
	struct bpf_prog *prog;
};
and
struct bpf_prog {
        u32                     jited:1,
                                len:31;
        struct sock_fprog_kern  *orig_prog;
        unsigned int            (*bpf_func)(const struct sk_buff *skb,
                                            const struct bpf_insn *filter);
        union {
                struct sock_filter      insns[0];
                struct bpf_insn         insnsi[0];
                struct work_struct      work;
        };
};
so that 'struct bpf_prog' can be used independent of sockets and cleans up
'unattached' bpf use cases

split SK_RUN_FILTER macro into:
    SK_RUN_FILTER to be used with 'struct sk_filter *' and
    BPF_PROG_RUN to be used with 'struct bpf_prog *'

__sk_filter_release(struct sk_filter *) gains
__bpf_prog_release(struct bpf_prog *) helper function

also perform related renames for the functions that work
with 'struct bpf_prog *', since they're on the same lines:

sk_filter_size -> bpf_prog_size
sk_filter_select_runtime -> bpf_prog_select_runtime
sk_filter_free -> bpf_prog_free
sk_unattached_filter_create -> bpf_prog_create
sk_unattached_filter_destroy -> bpf_prog_destroy
sk_store_orig_filter -> bpf_prog_store_orig_filter
sk_release_orig_filter -> bpf_release_orig_filter
__sk_migrate_filter -> bpf_migrate_filter
__sk_prepare_filter -> bpf_prepare_filter

API for attaching classic BPF to a socket stays the same:
sk_attach_filter(prog, struct sock *)/sk_detach_filter(struct sock *)
and SK_RUN_FILTER(struct sk_filter *, ctx) to execute a program
which is used by sockets, tun, af_packet

API for 'unattached' BPF programs becomes:
bpf_prog_create(struct bpf_prog **)/bpf_prog_destroy(struct bpf_prog *)
and BPF_PROG_RUN(struct bpf_prog *, ctx) to execute a program
which is used by isdn, ppp, team, seccomp, ptp, xt_bpf, cls_bpf, test_bpf

Signed-off-by: Alexei Starovoitov <ast@plumgrid.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/sched/cls_bpf.c

@@ -30,7 +30,7 @@ struct cls_bpf_head {
 };
 
 struct cls_bpf_prog {
-	struct sk_filter *filter;
+	struct bpf_prog *filter;
 	struct sock_filter *bpf_ops;
 	struct tcf_exts exts;
 	struct tcf_result res;
@@ -54,7 +54,7 @@ static int cls_bpf_classify(struct sk_buff *skb, const struct tcf_proto *tp,
 	int ret;
 
 	list_for_each_entry(prog, &head->plist, link) {
-		int filter_res = SK_RUN_FILTER(prog->filter, skb);
+		int filter_res = BPF_PROG_RUN(prog->filter, skb);
 
 		if (filter_res == 0)
 			continue;
@@ -92,7 +92,7 @@ static void cls_bpf_delete_prog(struct tcf_proto *tp, struct cls_bpf_prog *prog)
 	tcf_unbind_filter(tp, &prog->res);
 	tcf_exts_destroy(tp, &prog->exts);
 
-	sk_unattached_filter_destroy(prog->filter);
+	bpf_prog_destroy(prog->filter);
 
 	kfree(prog->bpf_ops);
 	kfree(prog);
@@ -161,7 +161,7 @@ static int cls_bpf_modify_existing(struct net *net, struct tcf_proto *tp,
 	struct sock_filter *bpf_ops, *bpf_old;
 	struct tcf_exts exts;
 	struct sock_fprog_kern tmp;
-	struct sk_filter *fp, *fp_old;
+	struct bpf_prog *fp, *fp_old;
 	u16 bpf_size, bpf_len;
 	u32 classid;
 	int ret;
@@ -193,7 +193,7 @@ static int cls_bpf_modify_existing(struct net *net, struct tcf_proto *tp,
 	tmp.len = bpf_len;
 	tmp.filter = bpf_ops;
 
-	ret = sk_unattached_filter_create(&fp, &tmp);
+	ret = bpf_prog_create(&fp, &tmp);
 	if (ret)
 		goto errout_free;
 
@@ -211,7 +211,7 @@ static int cls_bpf_modify_existing(struct net *net, struct tcf_proto *tp,
 	tcf_exts_change(tp, &prog->exts, &exts);
 
 	if (fp_old)
-		sk_unattached_filter_destroy(fp_old);
+		bpf_prog_destroy(fp_old);
 	if (bpf_old)
 		kfree(bpf_old);