This commits extends existing bpf maps memory charging API to support dynamic charging/uncharging.
This is required to account memory used by maps, if all entries are created dynamically after the map initialization. Signed-off-by: Roman Gushchin <[email protected]> Cc: Alexei Starovoitov <[email protected]> Cc: Daniel Borkmann <[email protected]> Acked-by: Martin KaFai Lau <[email protected]> --- include/linux/bpf.h | 2 ++ kernel/bpf/syscall.c | 53 +++++++++++++++++++++++++++++++++++++--------------- 2 files changed, 40 insertions(+), 15 deletions(-) diff --git a/include/linux/bpf.h b/include/linux/bpf.h index 7df32a3200f7..e4d684ce3f5e 100644 --- a/include/linux/bpf.h +++ b/include/linux/bpf.h @@ -434,6 +434,8 @@ struct bpf_map * __must_check bpf_map_inc(struct bpf_map *map, bool uref); void bpf_map_put_with_uref(struct bpf_map *map); void bpf_map_put(struct bpf_map *map); int bpf_map_precharge_memlock(u32 pages); +int bpf_map_charge_memlock(struct bpf_map *map, u32 pages); +void bpf_map_uncharge_memlock(struct bpf_map *map, u32 pages); void *bpf_map_area_alloc(size_t size, int numa_node); void bpf_map_area_free(void *base); void bpf_map_init_from_attr(struct bpf_map *map, union bpf_attr *attr); diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index 35dc466641f2..e03aeeec01e0 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -181,32 +181,55 @@ int bpf_map_precharge_memlock(u32 pages) return 0; } -static int bpf_map_charge_memlock(struct bpf_map *map) +static int bpf_charge_memlock(struct user_struct *user, u32 pages) { - struct user_struct *user = get_current_user(); - unsigned long memlock_limit; + unsigned long memlock_limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT; - memlock_limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT; + if (atomic_long_add_return(pages, &user->locked_vm) > memlock_limit) { + atomic_long_sub(pages, &user->locked_vm); + return -EPERM; + } + return 0; +} - atomic_long_add(map->pages, &user->locked_vm); +static int bpf_map_init_memlock(struct bpf_map *map) +{ + struct user_struct *user = get_current_user(); + int ret; - if (atomic_long_read(&user->locked_vm) > memlock_limit) { - atomic_long_sub(map->pages, &user->locked_vm); + ret = bpf_charge_memlock(user, map->pages); + if (ret) { free_uid(user); - return -EPERM; + return ret; } map->user = user; - return 0; + return ret; } -static void bpf_map_uncharge_memlock(struct bpf_map *map) +static void bpf_map_release_memlock(struct bpf_map *map) { struct user_struct *user = map->user; - - atomic_long_sub(map->pages, &user->locked_vm); + atomic_long_sub(map->pages, &map->user->locked_vm); free_uid(user); } +int bpf_map_charge_memlock(struct bpf_map *map, u32 pages) +{ + int ret; + + ret = bpf_charge_memlock(map->user, pages); + if (ret) + return ret; + map->pages += pages; + return ret; +} + +void bpf_map_uncharge_memlock(struct bpf_map *map, u32 pages) +{ + atomic_long_sub(pages, &map->user->locked_vm); + map->pages -= pages; +} + static int bpf_map_alloc_id(struct bpf_map *map) { int id; @@ -256,7 +279,7 @@ static void bpf_map_free_deferred(struct work_struct *work) { struct bpf_map *map = container_of(work, struct bpf_map, work); - bpf_map_uncharge_memlock(map); + bpf_map_release_memlock(map); security_bpf_map_free(map); /* implementation dependent freeing */ map->ops->map_free(map); @@ -492,7 +515,7 @@ static int map_create(union bpf_attr *attr) if (err) goto free_map_nouncharge; - err = bpf_map_charge_memlock(map); + err = bpf_map_init_memlock(map); if (err) goto free_map_sec; @@ -515,7 +538,7 @@ static int map_create(union bpf_attr *attr) return err; free_map: - bpf_map_uncharge_memlock(map); + bpf_map_release_memlock(map); free_map_sec: security_bpf_map_free(map); free_map_nouncharge: -- 2.14.4
