On Mon, Aug 25, 2014 at 2:33 PM, Cong Wang <cwang@xxxxxxxxxxxxxxxx> wrote: > On Sun, Aug 24, 2014 at 1:21 PM, Alexei Starovoitov <ast@xxxxxxxxxxxx> wrote: >> 'maps' is a generic storage of different types for sharing data between kernel >> and userspace. >> >> The maps are accessed from user space via BPF syscall, which has commands: >> >> - create a map with given type and attributes >> fd = bpf_map_create(map_type, struct nlattr *attr, int len) >> returns fd or negative error >> >> - lookup key in a given map referenced by fd >> err = bpf_map_lookup_elem(int fd, void *key, void *value) >> returns zero and stores found elem into value or negative error >> >> - create or update key/value pair in a given map >> err = bpf_map_update_elem(int fd, void *key, void *value) >> returns zero or negative error >> >> - find and delete element by key in a given map >> err = bpf_map_delete_elem(int fd, void *key) >> >> - iterate map elements (based on input key return next_key) >> err = bpf_map_get_next_key(int fd, void *key, void *next_key) > > > I think you need to document the bpf() syscall instead of wrappers on it, > from a developer's point of view. You will anyway need to document a new > syscall with a man page as a general rule. yep. I've mentioned before that man page is on todo list. I'm delaying writing it, because it's the most difficult part and I don't want to keep rewriting it when interface changes (like it did from global id to fd). Once implementation lands, manpage will be the highest priority. > In the changelog I mean something like: > > err = bpf(BPF_MAP_LOOKUP_ELEM, ...); Are you saying instead of: err = bpf_map_lookup_elem(int fd, void *key, void *value) write err = bpf(BPF_MAP_LOOKUP_ELEM, fd, key, value) in commit log? I think that style carries less information per line. For man page I'll document the syscall in a traditional way, but for commit log I like to have maximum info in the fewest lines. -- To unsubscribe from this list: send the line "unsubscribe linux-api" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
