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/isdn/i4l/isdn_ppp.c

@@ -379,12 +379,12 @@ isdn_ppp_release(int min, struct file *file)
 #endif
 #ifdef CONFIG_IPPP_FILTER
 	if (is->pass_filter) {
-		sk_unattached_filter_destroy(is->pass_filter);
+		bpf_prog_destroy(is->pass_filter);
 		is->pass_filter = NULL;
 	}
 
 	if (is->active_filter) {
-		sk_unattached_filter_destroy(is->active_filter);
+		bpf_prog_destroy(is->active_filter);
 		is->active_filter = NULL;
 	}
 #endif
@@ -639,12 +639,11 @@ isdn_ppp_ioctl(int min, struct file *file, unsigned int cmd, unsigned long arg)
 		fprog.filter = code;
 
 		if (is->pass_filter) {
-			sk_unattached_filter_destroy(is->pass_filter);
+			bpf_prog_destroy(is->pass_filter);
 			is->pass_filter = NULL;
 		}
 		if (fprog.filter != NULL)
-			err = sk_unattached_filter_create(&is->pass_filter,
-							  &fprog);
+			err = bpf_prog_create(&is->pass_filter, &fprog);
 		else
 			err = 0;
 		kfree(code);
@@ -664,12 +663,11 @@ isdn_ppp_ioctl(int min, struct file *file, unsigned int cmd, unsigned long arg)
 		fprog.filter = code;
 
 		if (is->active_filter) {
-			sk_unattached_filter_destroy(is->active_filter);
+			bpf_prog_destroy(is->active_filter);
 			is->active_filter = NULL;
 		}
 		if (fprog.filter != NULL)
-			err = sk_unattached_filter_create(&is->active_filter,
-							  &fprog);
+			err = bpf_prog_create(&is->active_filter, &fprog);
 		else
 			err = 0;
 		kfree(code);
@@ -1174,14 +1172,14 @@ isdn_ppp_push_higher(isdn_net_dev *net_dev, isdn_net_local *lp, struct sk_buff *
 	}
 
 	if (is->pass_filter
-	    && SK_RUN_FILTER(is->pass_filter, skb) == 0) {
+	    && BPF_PROG_RUN(is->pass_filter, skb) == 0) {
 		if (is->debug & 0x2)
 			printk(KERN_DEBUG "IPPP: inbound frame filtered.\n");
 		kfree_skb(skb);
 		return;
 	}
 	if (!(is->active_filter
-	      && SK_RUN_FILTER(is->active_filter, skb) == 0)) {
+	      && BPF_PROG_RUN(is->active_filter, skb) == 0)) {
 		if (is->debug & 0x2)
 			printk(KERN_DEBUG "IPPP: link-active filter: resetting huptimer.\n");
 		lp->huptimer = 0;
@@ -1320,14 +1318,14 @@ isdn_ppp_xmit(struct sk_buff *skb, struct net_device *netdev)
 	}
 
 	if (ipt->pass_filter
-	    && SK_RUN_FILTER(ipt->pass_filter, skb) == 0) {
+	    && BPF_PROG_RUN(ipt->pass_filter, skb) == 0) {
 		if (ipt->debug & 0x4)
 			printk(KERN_DEBUG "IPPP: outbound frame filtered.\n");
 		kfree_skb(skb);
 		goto unlock;
 	}
 	if (!(ipt->active_filter
-	      && SK_RUN_FILTER(ipt->active_filter, skb) == 0)) {
+	      && BPF_PROG_RUN(ipt->active_filter, skb) == 0)) {
 		if (ipt->debug & 0x4)
 			printk(KERN_DEBUG "IPPP: link-active filter: resetting huptimer.\n");
 		lp->huptimer = 0;
@@ -1517,9 +1515,9 @@ int isdn_ppp_autodial_filter(struct sk_buff *skb, isdn_net_local *lp)
 	}
 
 	drop |= is->pass_filter
-		&& SK_RUN_FILTER(is->pass_filter, skb) == 0;
+		&& BPF_PROG_RUN(is->pass_filter, skb) == 0;
 	drop |= is->active_filter
-		&& SK_RUN_FILTER(is->active_filter, skb) == 0;
+		&& BPF_PROG_RUN(is->active_filter, skb) == 0;
 
 	skb_push(skb, IPPP_MAX_HEADER - 4);
 	return drop;