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>

drivers/net/team/team_mode_loadbalance.c

@@ -58,7 +58,7 @@ struct lb_priv_ex {
 };
 
 struct lb_priv {
-	struct sk_filter __rcu *fp;
+	struct bpf_prog __rcu *fp;
 	lb_select_tx_port_func_t __rcu *select_tx_port_func;
 	struct lb_pcpu_stats __percpu *pcpu_stats;
 	struct lb_priv_ex *ex; /* priv extension */
@@ -174,14 +174,14 @@ static lb_select_tx_port_func_t *lb_select_tx_port_get_func(const char *name)
 static unsigned int lb_get_skb_hash(struct lb_priv *lb_priv,
 				    struct sk_buff *skb)
 {
-	struct sk_filter *fp;
+	struct bpf_prog *fp;
 	uint32_t lhash;
 	unsigned char *c;
 
 	fp = rcu_dereference_bh(lb_priv->fp);
 	if (unlikely(!fp))
 		return 0;
-	lhash = SK_RUN_FILTER(fp, skb);
+	lhash = BPF_PROG_RUN(fp, skb);
 	c = (char *) &lhash;
 	return c[0] ^ c[1] ^ c[2] ^ c[3];
 }
@@ -271,8 +271,8 @@ static void __fprog_destroy(struct sock_fprog_kern *fprog)
 static int lb_bpf_func_set(struct team *team, struct team_gsetter_ctx *ctx)
 {
 	struct lb_priv *lb_priv = get_lb_priv(team);
-	struct sk_filter *fp = NULL;
-	struct sk_filter *orig_fp = NULL;
+	struct bpf_prog *fp = NULL;
+	struct bpf_prog *orig_fp = NULL;
 	struct sock_fprog_kern *fprog = NULL;
 	int err;
 
@@ -281,7 +281,7 @@ static int lb_bpf_func_set(struct team *team, struct team_gsetter_ctx *ctx)
 				     ctx->data.bin_val.ptr);
 		if (err)
 			return err;
-		err = sk_unattached_filter_create(&fp, fprog);
+		err = bpf_prog_create(&fp, fprog);
 		if (err) {
 			__fprog_destroy(fprog);
 			return err;
@@ -300,7 +300,7 @@ static int lb_bpf_func_set(struct team *team, struct team_gsetter_ctx *ctx)
 
 	if (orig_fp) {
 		synchronize_rcu();
-		sk_unattached_filter_destroy(orig_fp);
+		bpf_prog_destroy(orig_fp);
 	}
 	return 0;
 }