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bpf: Add BPF_F_CPU and BPF_F_ALL_CPUS flags support for percpu_cgroup_storage maps

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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>
Link: https://lore.kernel.org/r/20260107022022.12843-6-leon.hwang@linux.dev
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This commit is contained in:
Leon Hwang
2026-01-07 10:20:20 +08:00
committed by Alexei Starovoitov
parent 8526397c3c
commit 47c79f05aa
4 changed files with 22 additions and 8 deletions
Download Patch File Download Diff File Expand all files Collapse all files

4
include/linux/bpf-cgroup.h
View File

@@ -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,

1
include/linux/bpf.h
View File

@@ -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;

23
kernel/bpf/local_storage.c
View File

@@ -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;
}

2
kernel/bpf/syscall.c
View File

@@ -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)) {