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bpf: Add BPF_F_CPU and BPF_F_ALL_CPUS flags support for percpu_array maps 

Introduce support for the BPF_F_ALL_CPUS flag in percpu_array maps to
allow updating values for all CPUs with a single value for both
update_elem and update_batch APIs.

Introduce support for the BPF_F_CPU flag in percpu_array maps to allow:

* update value for specified CPU for both update_elem and update_batch
APIs.
* lookup value for specified CPU for both lookup_elem and lookup_batch
APIs.

The BPF_F_CPU flag is passed via:

* map_flags of lookup_elem and update_elem APIs along with embedded cpu
info.
* elem_flags of lookup_batch and update_batch APIs along with embedded
cpu info.

Signed-off-by: Leon Hwang <leon.hwang@linux.dev>
Link: https://lore.kernel.org/r/20260107022022.12843-3-leon.hwang@linux.dev
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
master
Leon Hwang 2026-01-07 10:20:17 +08:00 committed by Alexei Starovoitov
parent 2b421662c7
commit 8eb76cb03f
3 changed files with 32 additions and 10 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

9
include/linux/bpf.h
View File

@ -2848,7 +2848,7 @@ int map_set_for_each_callback_args(struct bpf_verifier_env *env,
struct bpf_func_state *callee);
int bpf_percpu_hash_copy(struct bpf_map *map, void *key, void *value);
int bpf_percpu_array_copy(struct bpf_map *map, void *key, void *value);
int bpf_percpu_array_copy(struct bpf_map *map, void *key, void *value, u64 flags);
int bpf_percpu_hash_update(struct bpf_map *map, void *key, void *value,
u64 flags);
int bpf_percpu_array_update(struct bpf_map *map, void *key, void *value,
@ -3917,7 +3917,12 @@ bpf_prog_update_insn_ptrs(struct bpf_prog *prog, u32 *offsets, void *image)
static inline bool bpf_map_supports_cpu_flags(enum bpf_map_type map_type)
{
return false;
switch (map_type) {
case BPF_MAP_TYPE_PERCPU_ARRAY:
return true;
default:
return false;
}
}
static inline int bpf_map_check_op_flags(struct bpf_map *map, u64 flags, u64 allowed_flags)

31
kernel/bpf/arraymap.c
View File

@ -307,7 +307,7 @@ static void *percpu_array_map_lookup_percpu_elem(struct bpf_map *map, void *key,
return per_cpu_ptr(array->pptrs[index & array->index_mask], cpu);
}
int bpf_percpu_array_copy(struct bpf_map *map, void *key, void *value)
int bpf_percpu_array_copy(struct bpf_map *map, void *key, void *value, u64 map_flags)
{
struct bpf_array *array = container_of(map, struct bpf_array, map);
u32 index = *(u32 *)key;
@ -325,11 +325,18 @@ int bpf_percpu_array_copy(struct bpf_map *map, void *key, void *value)
size = array->elem_size;
rcu_read_lock();
pptr = array->pptrs[index & array->index_mask];
if (map_flags & BPF_F_CPU) {
cpu = map_flags >> 32;
copy_map_value(map, value, per_cpu_ptr(pptr, cpu));
check_and_init_map_value(map, value);
goto unlock;
}
for_each_possible_cpu(cpu) {
copy_map_value_long(map, value + off, per_cpu_ptr(pptr, cpu));
check_and_init_map_value(map, value + off);
off += size;
}
unlock:
rcu_read_unlock();
return 0;
}
@ -398,10 +405,11 @@ int bpf_percpu_array_update(struct bpf_map *map, void *key, void *value,
struct bpf_array *array = container_of(map, struct bpf_array, map);
u32 index = *(u32 *)key;
void __percpu *pptr;
int cpu, off = 0;
void *ptr, *val;
u32 size;
int cpu;
if (unlikely(map_flags > BPF_EXIST))
if (unlikely((map_flags & BPF_F_LOCK) || (u32)map_flags > BPF_F_ALL_CPUS))
/* unknown flags */
return -EINVAL;
@ -422,11 +430,20 @@ int bpf_percpu_array_update(struct bpf_map *map, void *key, void *value,
size = array->elem_size;
rcu_read_lock();
pptr = array->pptrs[index & array->index_mask];
for_each_possible_cpu(cpu) {
copy_map_value_long(map, per_cpu_ptr(pptr, cpu), value + off);
bpf_obj_free_fields(array->map.record, per_cpu_ptr(pptr, cpu));
off += size;
if (map_flags & BPF_F_CPU) {
cpu = map_flags >> 32;
ptr = per_cpu_ptr(pptr, cpu);
copy_map_value(map, ptr, value);
bpf_obj_free_fields(array->map.record, ptr);
goto unlock;
}
for_each_possible_cpu(cpu) {
ptr = per_cpu_ptr(pptr, cpu);
val = (map_flags & BPF_F_ALL_CPUS) ? value : value + size * cpu;
copy_map_value(map, ptr, val);
bpf_obj_free_fields(array->map.record, ptr);
}
unlock:
rcu_read_unlock();
return 0;
}

2
kernel/bpf/syscall.c
View File

@ -318,7 +318,7 @@ static int bpf_map_copy_value(struct bpf_map *map, void *key, void *value,
map->map_type == BPF_MAP_TYPE_LRU_PERCPU_HASH) {
err = bpf_percpu_hash_copy(map, key, value);
} else if (map->map_type == BPF_MAP_TYPE_PERCPU_ARRAY) {
err = bpf_percpu_array_copy(map, key, value);
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);
} else if (map->map_type == BPF_MAP_TYPE_STACK_TRACE) {