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, 28 insertions, 10 deletions

diff --git a/include/linux/bpf-cgroup.h b/include/linux/bpf-cgroup.h
index f91b0f8ff3a9..e9871b012dac 100644
--- a/include/linux/bpf-cgroup.h
+++ b/include/linux/bpf-cgroup.h
@@ -2,6 +2,7 @@
 #ifndef _BPF_CGROUP_H
 #define _BPF_CGROUP_H
 
+#include <linux/bpf.h>
 #include <linux/errno.h>
 #include <linux/jump_label.h>
 #include <linux/percpu.h>
@@ -22,7 +23,10 @@ struct bpf_cgroup_storage;
 extern struct static_key_false cgroup_bpf_enabled_key;
 #define cgroup_bpf_enabled static_branch_unlikely(&cgroup_bpf_enabled_key)
 
-DECLARE_PER_CPU(void*, bpf_cgroup_storage);
+DECLARE_PER_CPU(void*, bpf_cgroup_storage[MAX_BPF_CGROUP_STORAGE_TYPE]);
+
+#define for_each_cgroup_storage_type(stype) \
+	for (stype = 0; stype < MAX_BPF_CGROUP_STORAGE_TYPE; stype++)
 
 struct bpf_cgroup_storage_map;
 
@@ -43,7 +47,7 @@ struct bpf_cgroup_storage {
 struct bpf_prog_list {
 	struct list_head node;
 	struct bpf_prog *prog;
-	struct bpf_cgroup_storage *storage;
+	struct bpf_cgroup_storage *storage[MAX_BPF_CGROUP_STORAGE_TYPE];
 };
 
 struct bpf_prog_array;
@@ -101,18 +105,29 @@ int __cgroup_bpf_run_filter_sock_ops(struct sock *sk,
 int __cgroup_bpf_check_dev_permission(short dev_type, u32 major, u32 minor,
 				      short access, enum bpf_attach_type type);
 
-static inline void bpf_cgroup_storage_set(struct bpf_cgroup_storage *storage)
+static inline enum bpf_cgroup_storage_type cgroup_storage_type(
+	struct bpf_map *map)
 {
+	return BPF_CGROUP_STORAGE_SHARED;
+}
+
+static inline void bpf_cgroup_storage_set(struct bpf_cgroup_storage
+					  *storage[MAX_BPF_CGROUP_STORAGE_TYPE])
+{
+	enum bpf_cgroup_storage_type stype;
 	struct bpf_storage_buffer *buf;
 
-	if (!storage)
-		return;
+	for_each_cgroup_storage_type(stype) {
+		if (!storage[stype])
+			continue;
 
-	buf = READ_ONCE(storage->buf);
-	this_cpu_write(bpf_cgroup_storage, &buf->data[0]);
+		buf = READ_ONCE(storage[stype]->buf);
+		this_cpu_write(bpf_cgroup_storage[stype], &buf->data[0]);
+	}
 }
 
-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);
 void bpf_cgroup_storage_free(struct bpf_cgroup_storage *storage);
 void bpf_cgroup_storage_link(struct bpf_cgroup_storage *storage,
 			     struct cgroup *cgroup,
@@ -265,13 +280,14 @@ static inline int cgroup_bpf_prog_query(const union bpf_attr *attr,
 	return -EINVAL;
 }
 
-static inline void bpf_cgroup_storage_set(struct bpf_cgroup_storage *storage) {}
+static inline void bpf_cgroup_storage_set(
+	struct bpf_cgroup_storage *storage[MAX_BPF_CGROUP_STORAGE_TYPE]) {}
 static inline int bpf_cgroup_storage_assign(struct bpf_prog *prog,
 					    struct bpf_map *map) { return 0; }
 static inline void bpf_cgroup_storage_release(struct bpf_prog *prog,
 					      struct bpf_map *map) {}
 static inline struct bpf_cgroup_storage *bpf_cgroup_storage_alloc(
-	struct bpf_prog *prog) { return 0; }
+	struct bpf_prog *prog, enum bpf_cgroup_storage_type stype) { return 0; }
 static inline void bpf_cgroup_storage_free(
 	struct bpf_cgroup_storage *storage) {}
 
@@ -293,6 +309,8 @@ static inline void bpf_cgroup_storage_free(
 #define BPF_CGROUP_RUN_PROG_SOCK_OPS(sock_ops) ({ 0; })
 #define BPF_CGROUP_RUN_PROG_DEVICE_CGROUP(type,major,minor,access) ({ 0; })
 
+#define for_each_cgroup_storage_type(stype) for (; false; )
+
 #endif /* CONFIG_CGROUP_BPF */
 
 #endif /* _BPF_CGROUP_H */