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Message-ID: <20251117162033.6296-7-leon.hwang@linux.dev>
Date: Tue, 18 Nov 2025 00:20:31 +0800
From: Leon Hwang <leon.hwang@...ux.dev>
To: bpf@...r.kernel.org
Cc: ast@...nel.org,
andrii@...nel.org,
daniel@...earbox.net,
jolsa@...nel.org,
yonghong.song@...ux.dev,
song@...nel.org,
eddyz87@...il.com,
dxu@...uu.xyz,
deso@...teo.net,
martin.lau@...ux.dev,
john.fastabend@...il.com,
kpsingh@...nel.org,
sdf@...ichev.me,
haoluo@...gle.com,
shuah@...nel.org,
kerneljasonxing@...il.com,
chen.dylane@...ux.dev,
willemb@...gle.com,
paul.chaignon@...il.com,
a.s.protopopov@...il.com,
memxor@...il.com,
yatsenko@...a.com,
tklauser@...tanz.ch,
leon.hwang@...ux.dev,
kernel-patches-bot@...com,
linux-kernel@...r.kernel.org,
linux-kselftest@...r.kernel.org
Subject: [PATCH bpf-next v10 6/8] 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: Leon Hwang <leon.hwang@...ux.dev>
---
include/linux/bpf-cgroup.h | 4 ++--
include/linux/bpf.h | 1 +
kernel/bpf/local_storage.c | 23 ++++++++++++++++++-----
kernel/bpf/syscall.c | 2 +-
4 files changed, 22 insertions(+), 8 deletions(-)
diff --git a/include/linux/bpf-cgroup.h b/include/linux/bpf-cgroup.h
index aedf573bdb426..013f4db9903fd 100644
--- a/include/linux/bpf-cgroup.h
+++ b/include/linux/bpf-cgroup.h
@@ -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);
@@ -467,7 +467,7 @@ 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,
diff --git a/include/linux/bpf.h b/include/linux/bpf.h
index 1fc0afb7f547f..e87779d3c5927 100644
--- a/include/linux/bpf.h
+++ b/include/linux/bpf.h
@@ -3819,6 +3819,7 @@ 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 2ab4b60ffe61f..1ccbf28b2ad9f 100644
--- a/kernel/bpf/local_storage.c
+++ b/kernel/bpf/local_storage.c
@@ -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;
}
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index 3cff19a4be527..643e589c10231 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -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)) {
--
2.51.2
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