ebpf: move read-only fields to bpf_prog and shrink bpf_prog_aux

is_gpl_compatible and prog_type should be moved directly into bpf_prog
as they stay immutable during bpf_prog's lifetime, are core attributes
and they can be locked as read-only later on via bpf_prog_select_runtime().

With a bit of rearranging, this also allows us to shrink bpf_prog_aux
to exactly 1 cacheline.

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

2 files changed, 5 insertions, 6 deletions

diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index 536edc2be307..0d69449acbd0 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -354,10 +354,11 @@ static int find_prog_type(enum bpf_prog_type type, struct bpf_prog *prog)
         list_for_each_entry(tl, &bpf_prog_types, list_node) {
                 if (tl->type == type) {
                         prog->aux->ops = tl->ops;
-                        prog->aux->prog_type = type;
+                        prog->type = type;
                         return 0;
                 }
         }
+
         return -EINVAL;
 }
 
@@ -508,7 +509,7 @@ static int bpf_prog_load(union bpf_attr *attr)
         prog->jited = false;
 
         atomic_set(&prog->aux->refcnt, 1);
-        prog->aux->is_gpl_compatible = is_gpl;
+        prog->gpl_compatible = is_gpl;
 
         /* find program type: socket_filter vs tracing_filter */
         err = find_prog_type(type, prog);
@@ -517,7 +518,6 @@ static int bpf_prog_load(union bpf_attr *attr)
 
         /* run eBPF verifier */
         err = bpf_check(prog, attr);
-
         if (err < 0)
                 goto free_used_maps;
 
@@ -528,7 +528,6 @@ static int bpf_prog_load(union bpf_attr *attr)
         bpf_prog_select_runtime(prog);
 
         err = anon_inode_getfd("bpf-prog", &bpf_prog_fops, prog, O_RDWR | O_CLOEXEC);
-
         if (err < 0)
                 /* failed to allocate fd */
                 goto free_used_maps;
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index 594d341f04db..bdf4192a889b 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -852,7 +852,7 @@ static int check_call(struct verifier_env *env, int func_id)
         }
 
         /* eBPF programs must be GPL compatible to use GPL-ed functions */
-        if (!env->prog->aux->is_gpl_compatible && fn->gpl_only) {
+        if (!env->prog->gpl_compatible && fn->gpl_only) {
                 verbose("cannot call GPL only function from proprietary program\n");
                 return -EINVAL;
         }
@@ -1205,7 +1205,7 @@ static int check_ld_abs(struct verifier_env *env, struct bpf_insn *insn)
         struct reg_state *reg;
         int i, err;
 
-        if (!may_access_skb(env->prog->aux->prog_type)) {
+        if (!may_access_skb(env->prog->type)) {
                 verbose("BPF_LD_ABS|IND instructions not allowed for this program type\n");
                 return -EINVAL;
         }