On Thu, Oct 18, 2018 at 6:16 AM Mauricio Vasquez B <mauricio.vasq...@polito.it> wrote: > > The previous patch implemented a bpf queue/stack maps that > provided the peek/pop/push functions. There is not a direct > relationship between those functions and the current maps > syscalls, hence a new MAP_LOOKUP_AND_DELETE_ELEM syscall is added, > this is mapped to the pop operation in the queue/stack maps > and it is still to implement in other kind of maps. > > Signed-off-by: Mauricio Vasquez B <mauricio.vasq...@polito.it>
Acked-by: Song Liu <songliubrav...@fb.com> > --- > include/uapi/linux/bpf.h | 1 + > kernel/bpf/syscall.c | 66 > ++++++++++++++++++++++++++++++++++++++++++++++ > 2 files changed, 67 insertions(+) > > diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h > index b8fc161c5b78..c8824d5364ff 100644 > --- a/include/uapi/linux/bpf.h > +++ b/include/uapi/linux/bpf.h > @@ -103,6 +103,7 @@ enum bpf_cmd { > BPF_BTF_LOAD, > BPF_BTF_GET_FD_BY_ID, > BPF_TASK_FD_QUERY, > + BPF_MAP_LOOKUP_AND_DELETE_ELEM, > }; > > enum bpf_map_type { > diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c > index 1617407f9ee5..49ae64a26562 100644 > --- a/kernel/bpf/syscall.c > +++ b/kernel/bpf/syscall.c > @@ -999,6 +999,69 @@ static int map_get_next_key(union bpf_attr *attr) > return err; > } > > +#define BPF_MAP_LOOKUP_AND_DELETE_ELEM_LAST_FIELD value > + > +static int map_lookup_and_delete_elem(union bpf_attr *attr) > +{ > + void __user *ukey = u64_to_user_ptr(attr->key); > + void __user *uvalue = u64_to_user_ptr(attr->value); > + int ufd = attr->map_fd; > + struct bpf_map *map; > + void *key, *value, *ptr; > + u32 value_size; > + struct fd f; > + int err; > + > + if (CHECK_ATTR(BPF_MAP_LOOKUP_AND_DELETE_ELEM)) > + return -EINVAL; > + > + f = fdget(ufd); > + map = __bpf_map_get(f); > + if (IS_ERR(map)) > + return PTR_ERR(map); > + > + if (!(f.file->f_mode & FMODE_CAN_WRITE)) { > + err = -EPERM; > + goto err_put; > + } > + > + key = __bpf_copy_key(ukey, map->key_size); > + if (IS_ERR(key)) { > + err = PTR_ERR(key); > + goto err_put; > + } > + > + value_size = map->value_size; > + > + err = -ENOMEM; > + value = kmalloc(value_size, GFP_USER | __GFP_NOWARN); > + if (!value) > + goto free_key; > + > + if (map->map_type == BPF_MAP_TYPE_QUEUE || > + map->map_type == BPF_MAP_TYPE_STACK) { > + err = map->ops->map_pop_elem(map, value); > + } else { > + err = -ENOTSUPP; > + } > + > + if (err) > + goto free_value; > + > + if (copy_to_user(uvalue, value, value_size) != 0) > + goto free_value; > + > + err = 0; > + > +free_value: > + kfree(value); > +free_key: > + kfree(key); > +err_put: > + fdput(f); > + return err; > +} > + > static const struct bpf_prog_ops * const bpf_prog_types[] = { > #define BPF_PROG_TYPE(_id, _name) \ > [_id] = & _name ## _prog_ops, > @@ -2472,6 +2535,9 @@ SYSCALL_DEFINE3(bpf, int, cmd, union bpf_attr __user *, > uattr, unsigned int, siz > case BPF_TASK_FD_QUERY: > err = bpf_task_fd_query(&attr, uattr); > break; > + case BPF_MAP_LOOKUP_AND_DELETE_ELEM: > + err = map_lookup_and_delete_elem(&attr); > + break; > default: > err = -EINVAL; > break; >