bpf: extend cgroup bpf core to allow multiple cgroup storage types

In order to introduce per-cpu cgroup storage, let's generalize
bpf cgroup core to support multiple cgroup storage types.
Potentially, per-node cgroup storage can be added later.

This commit is mostly a formal change that replaces
cgroup_storage pointer with a array of cgroup_storage pointers.
It doesn't actually introduce a new storage type,
it will be done later.

Each bpf program is now able to have one cgroup storage of each type.

Signed-off-by: Roman Gushchin <guro@fb.com>
Acked-by: Song Liu <songliubraving@fb.com>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

1 files changed, 11 insertions, 7 deletions

diff --git a/kernel/bpf/local_storage.c b/kernel/bpf/local_storage.c
index 22ad967d1e5f..0bd9f19fc557 100644
--- a/kernel/bpf/local_storage.c
+++ b/kernel/bpf/local_storage.c
@@ -7,7 +7,7 @@
 #include <linux/rbtree.h>
 #include <linux/slab.h>
 
-DEFINE_PER_CPU(void*, bpf_cgroup_storage);
+DEFINE_PER_CPU(void*, bpf_cgroup_storage[MAX_BPF_CGROUP_STORAGE_TYPE]);
 
 #ifdef CONFIG_CGROUP_BPF
 
@@ -251,6 +251,7 @@ const struct bpf_map_ops cgroup_storage_map_ops = {
 
 int bpf_cgroup_storage_assign(struct bpf_prog *prog, struct bpf_map *_map)
 {
+        enum bpf_cgroup_storage_type stype = cgroup_storage_type(_map);
         struct bpf_cgroup_storage_map *map = map_to_storage(_map);
         int ret = -EBUSY;
 
@@ -258,11 +259,12 @@ int bpf_cgroup_storage_assign(struct bpf_prog *prog, struct bpf_map *_map)
 
         if (map->prog && map->prog != prog)
                 goto unlock;
-        if (prog->aux->cgroup_storage && prog->aux->cgroup_storage != _map)
+        if (prog->aux->cgroup_storage[stype] &&
+            prog->aux->cgroup_storage[stype] != _map)
                 goto unlock;
 
         map->prog = prog;
-        prog->aux->cgroup_storage = _map;
+        prog->aux->cgroup_storage[stype] = _map;
         ret = 0;
 unlock:
         spin_unlock_bh(&map->lock);
@@ -272,24 +274,26 @@ unlock:
 
 void bpf_cgroup_storage_release(struct bpf_prog *prog, struct bpf_map *_map)
 {
+        enum bpf_cgroup_storage_type stype = cgroup_storage_type(_map);
         struct bpf_cgroup_storage_map *map = map_to_storage(_map);
 
         spin_lock_bh(&map->lock);
         if (map->prog == prog) {
-                WARN_ON(prog->aux->cgroup_storage != _map);
+                WARN_ON(prog->aux->cgroup_storage[stype] != _map);
                 map->prog = NULL;
-                prog->aux->cgroup_storage = NULL;
+                prog->aux->cgroup_storage[stype] = NULL;
         }
         spin_unlock_bh(&map->lock);
 }
 
-struct bpf_cgroup_storage *bpf_cgroup_storage_alloc(struct bpf_prog *prog)
+struct bpf_cgroup_storage *bpf_cgroup_storage_alloc(struct bpf_prog *prog,
+                                        enum bpf_cgroup_storage_type stype)
 {
         struct bpf_cgroup_storage *storage;
         struct bpf_map *map;
         u32 pages;
 
-        map = prog->aux->cgroup_storage;
+        map = prog->aux->cgroup_storage[stype];
         if (!map)
                 return NULL;