[PATCH bpf-next v5 7/9] bpf: Add BPF_F_CPU and BPF_F_ALL_CPUS flags support for percpu_cgroup_storage maps

[Leon Hwang <leon.hwang@linux.dev>]

Introduce BPF_F_ALL_CPUS flag support for percpu_cgroup_storage maps to
allow updating values for all CPUs with a single value for update_elem
API.

Introduce BPF_F_CPU flag support for percpu_cgroup_storage maps to
allow:

* update value for specified CPU for update_elem API.
* lookup value for specified CPU for lookup_elem API.

The BPF_F_CPU flag is passed via map_flags along with embedded cpu info.

Signed-off-by: Leon Hwang <leon.hwang@linux.dev>
---
 include/linux/bpf.h        |  1 +
 kernel/bpf/local_storage.c | 12 +++++++++++-
 2 files changed, 12 insertions(+), 1 deletion(-)

diff --git a/include/linux/bpf.h b/include/linux/bpf.h
index 2254aafc93773..c6010a2a42225 100644
--- a/include/linux/bpf.h
+++ b/include/linux/bpf.h
@@ -3758,6 +3758,7 @@ static inline bool bpf_map_supports_cpu_flags(enum bpf_map_type map_type)
 	case BPF_MAP_TYPE_PERCPU_ARRAY:
 	case BPF_MAP_TYPE_PERCPU_HASH:
 	case BPF_MAP_TYPE_LRU_PERCPU_HASH:
+	case BPF_MAP_TYPE_PERCPU_CGROUP_STORAGE:
 		return true;
 	default:
 		return false;
diff --git a/kernel/bpf/local_storage.c b/kernel/bpf/local_storage.c
index f63639c79902a..a4ba173e4c44f 100644
--- a/kernel/bpf/local_storage.c
+++ b/kernel/bpf/local_storage.c
@@ -186,6 +186,11 @@ int bpf_percpu_cgroup_storage_copy(struct bpf_map *_map, void *key,
 	struct bpf_cgroup_storage *storage;
 	void __percpu *pptr;
 	u32 size;
+	int err;
+
+	err = bpf_map_check_cpu_flags(map_flags, false);
+	if (err)
+		return err;
 
 	rcu_read_lock();
 	storage = cgroup_storage_lookup(map, key, false);
@@ -212,10 +217,15 @@ int bpf_percpu_cgroup_storage_update(struct bpf_map *_map, void *key,
 	struct bpf_cgroup_storage *storage;
 	void __percpu *pptr;
 	u32 size;
+	int err;
 
-	if (map_flags != BPF_ANY && map_flags != BPF_EXIST)
+	if ((u32)map_flags & ~(BPF_ANY | BPF_EXIST | BPF_F_CPU | BPF_F_ALL_CPUS))
 		return -EINVAL;
 
+	err = bpf_map_check_cpu_flags(map_flags, true);
+	if (err)
+		return err;
+
 	rcu_read_lock();
 	storage = cgroup_storage_lookup(map, key, false);
 	if (!storage) {
-- 
2.50.1