Commit 47c79f05 authored by Leon Hwang's avatar Leon Hwang Committed by Alexei Starovoitov
Browse files

bpf: Add BPF_F_CPU and BPF_F_ALL_CPUS flags support for percpu_cgroup_storage maps 



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: default avatarLeon Hwang <leon.hwang@linux.dev>
Link: https://lore.kernel.org/r/20260107022022.12843-6-leon.hwang@linux.dev


Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
parent 8526397c

include/linux/bpf-cgroup.h

+2 −2
Original line number Diff line number Diff line
@@ -172,7 +172,7 @@ void bpf_cgroup_storage_link(struct bpf_cgroup_storage *storage, 
void bpf_cgroup_storage_unlink(struct bpf_cgroup_storage *storage);

int bpf_cgroup_storage_assign(struct bpf_prog_aux *aux, struct bpf_map *map);



int bpf_percpu_cgroup_storage_copy(struct bpf_map *map, void *key, void *value);

int bpf_percpu_cgroup_storage_copy(struct bpf_map *map, void *key, void *value, u64 flags);

int bpf_percpu_cgroup_storage_update(struct bpf_map *map, void *key,

				     void *value, u64 flags);
@@ -470,7 +470,7 @@ static inline struct bpf_cgroup_storage *bpf_cgroup_storage_alloc( 
static inline void bpf_cgroup_storage_free(

	struct bpf_cgroup_storage *storage) {}

static inline int bpf_percpu_cgroup_storage_copy(struct bpf_map *map, void *key,

						 void *value) {

						 void *value, u64 flags) {

	return 0;

}

static inline int bpf_percpu_cgroup_storage_update(struct bpf_map *map,

include/linux/bpf.h

+1 −0
Original line number Diff line number Diff line
@@ -3921,6 +3921,7 @@ 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;

kernel/bpf/local_storage.c

+18 −5
Original line number Diff line number Diff line
@@ -180,7 +180,7 @@ static long cgroup_storage_update_elem(struct bpf_map *map, void *key, 
}



int bpf_percpu_cgroup_storage_copy(struct bpf_map *_map, void *key,

				   void *value)

				   void *value, u64 map_flags)

{

	struct bpf_cgroup_storage_map *map = map_to_storage(_map);

	struct bpf_cgroup_storage *storage;
@@ -198,11 +198,17 @@ int bpf_percpu_cgroup_storage_copy(struct bpf_map *_map, void *key, 
	 * access 'value_size' of them, so copying rounded areas

	 * will not leak any kernel data

	 */

	if (map_flags & BPF_F_CPU) {

		cpu = map_flags >> 32;

		copy_map_value(_map, value, per_cpu_ptr(storage->percpu_buf, cpu));

		goto unlock;

	}

	size = round_up(_map->value_size, 8);

	for_each_possible_cpu(cpu) {

		copy_map_value_long(_map, value + off, per_cpu_ptr(storage->percpu_buf, cpu));

		off += size;

	}

unlock:

	rcu_read_unlock();

	return 0;

}
@@ -212,10 +218,11 @@ int bpf_percpu_cgroup_storage_update(struct bpf_map *_map, void *key, 
{

	struct bpf_cgroup_storage_map *map = map_to_storage(_map);

	struct bpf_cgroup_storage *storage;

	int cpu, off = 0;

	void *val;

	u32 size;

	int cpu;



	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;



	rcu_read_lock();
@@ -231,11 +238,17 @@ int bpf_percpu_cgroup_storage_update(struct bpf_map *_map, void *key, 
	 * returned or zeros which were zero-filled by percpu_alloc,

	 * so no kernel data leaks possible

	 */

	if (map_flags & BPF_F_CPU) {

		cpu = map_flags >> 32;

		copy_map_value(_map, per_cpu_ptr(storage->percpu_buf, cpu), value);

		goto unlock;

	}

	size = round_up(_map->value_size, 8);

	for_each_possible_cpu(cpu) {

		copy_map_value_long(_map, per_cpu_ptr(storage->percpu_buf, cpu), value + off);

		off += size;

		val = (map_flags & BPF_F_ALL_CPUS) ? value : value + size * cpu;

		copy_map_value(_map, per_cpu_ptr(storage->percpu_buf, cpu), val);

	}

unlock:

	rcu_read_unlock();

	return 0;

}

kernel/bpf/syscall.c

+1 −1
Original line number Diff line number Diff line
@@ -320,7 +320,7 @@ static int bpf_map_copy_value(struct bpf_map *map, void *key, void *value, 
	} else if (map->map_type == BPF_MAP_TYPE_PERCPU_ARRAY) {

		err = bpf_percpu_array_copy(map, key, value, flags);

	} else if (map->map_type == BPF_MAP_TYPE_PERCPU_CGROUP_STORAGE) {

		err = bpf_percpu_cgroup_storage_copy(map, key, value);

		err = bpf_percpu_cgroup_storage_copy(map, key, value, flags);

	} else if (map->map_type == BPF_MAP_TYPE_STACK_TRACE) {

		err = bpf_stackmap_extract(map, key, value, false);

	} else if (IS_FD_ARRAY(map) || IS_FD_PROG_ARRAY(map)) {