Re: [PATCH bpf-next v1 3/7] tools: bpftool: create map of maps
From: Quentin Monnet
Date: Wed Mar 20 2019 - 15:00:40 EST
Hi Alban, thanks for those patches!
2019-03-20 18:33 UTC+0100 ~ Alban Crequy <alban.crequy@xxxxxxxxx>
> From: Alban Crequy <alban@xxxxxxxxxx>
>
> Before this patch, there was no way to fill attr.inner_map_fd, necessary
> for array_of_maps or hash_of_maps.
>
> This patch adds keyword 'innermap' to pass the innermap, either as an id
> or as a pinned map.
>
> Example of commands:
>
> $ sudo bpftool map create /sys/fs/bpf/innermap type hash \
> key 8 value 8 entries 64 name innermap flags 1
> $ sudo bpftool map create /sys/fs/bpf/outermap type hash_of_maps \
> innermap pinned /sys/fs/bpf/innermap key 64 value 4 \
> entries 64 name myoutermap flags 1
> $ sudo bpftool map show pinned /sys/fs/bpf/outermap
> 47: hash_of_maps name myoutermap flags 0x1
> key 64B value 4B max_entries 64 memlock 12288B
>
> Documentation and bash completion updated as well.
>
> Signed-off-by: Alban Crequy <alban@xxxxxxxxxx>
>
> ---
>
> Previous version of this patch was sent while bpf-next was closed.
> https://marc.info/?l=linux-kernel&m=155180393501258&w=2
>
> Since then, the following changes were done:
> - error management when calling map_parse_fd (review from Jakub)
> - fix documentation and bash completion (review from Quentin)
> ---
> .../bpf/bpftool/Documentation/bpftool-map.rst | 9 ++-
> tools/bpf/bpftool/bash-completion/bpftool | 9 +++
> tools/bpf/bpftool/map.c | 75 +++++++++++++++++--
> 3 files changed, 83 insertions(+), 10 deletions(-)
>
> diff --git a/tools/bpf/bpftool/Documentation/bpftool-map.rst b/tools/bpf/bpftool/Documentation/bpftool-map.rst
> index 5c984ffc9f01..b685641bfd74 100644
> --- a/tools/bpf/bpftool/Documentation/bpftool-map.rst
> +++ b/tools/bpf/bpftool/Documentation/bpftool-map.rst
> @@ -23,7 +23,7 @@ MAP COMMANDS
>
> | **bpftool** **map { show | list }** [*MAP*]
> | **bpftool** **map create** *FILE* **type** *TYPE* **key** *KEY_SIZE* **value** *VALUE_SIZE* \
> -| **entries** *MAX_ENTRIES* **name** *NAME* [**flags** *FLAGS*] [**dev** *NAME*]
> +| **entries** *MAX_ENTRIES* **name** *NAME* [**flags** *FLAGS*] [**dev** *NAME*] [**innermap** MAP]
> | **bpftool** **map dump** *MAP*
> | **bpftool** **map update** *MAP* [**key** *DATA*] [**value** *VALUE*] [*UPDATE_FLAGS*]
> | **bpftool** **map lookup** *MAP* [**key** *DATA*]
> @@ -60,10 +60,15 @@ DESCRIPTION
> Output will start with map ID followed by map type and
> zero or more named attributes (depending on kernel version).
>
> - **bpftool map create** *FILE* **type** *TYPE* **key** *KEY_SIZE* **value** *VALUE_SIZE* **entries** *MAX_ENTRIES* **name** *NAME* [**flags** *FLAGS*] [**dev** *NAME*]
> + **bpftool map create** *FILE* **type** *TYPE* **key** *KEY_SIZE* **value** *VALUE_SIZE* **entries** *MAX_ENTRIES* **name** *NAME* [**flags** *FLAGS*] [**dev** *NAME*] [**innermap** MAP]
> Create a new map with given parameters and pin it to *bpffs*
> as *FILE*.
>
> + To create a map of type **array_of_maps** or
> + **hash_of_maps**, the additional parameter **innermap** needs
> + to reference an existing map with the type and size of the
> + maps in the values.
> +
> **bpftool map dump** *MAP*
> Dump all entries in a given *MAP*.
>
> diff --git a/tools/bpf/bpftool/bash-completion/bpftool b/tools/bpf/bpftool/bash-completion/bpftool
> index b803827d01e8..9e37de8bb227 100644
> --- a/tools/bpf/bpftool/bash-completion/bpftool
> +++ b/tools/bpf/bpftool/bash-completion/bpftool
> @@ -461,6 +461,14 @@ _bpftool()
> _sysfs_get_netdevs
> return 0
> ;;
> + innermap)
> + COMPREPLY+=( $( compgen -W "id pinned" -- "$cur" ) )
> + return 0
> + ;;
> + id)
> + _bpftool_get_map_ids
> + return 0
> + ;;
> *)
> _bpftool_once_attr 'type'
> _bpftool_once_attr 'key'
> @@ -469,6 +477,7 @@ _bpftool()
> _bpftool_once_attr 'name'
> _bpftool_once_attr 'flags'
> _bpftool_once_attr 'dev'
> + _bpftool_once_attr 'innermap'
> return 0
> ;;
> esac
> diff --git a/tools/bpf/bpftool/map.c b/tools/bpf/bpftool/map.c
> index 18f9bc3aed4f..a576f2a019be 100644
> --- a/tools/bpf/bpftool/map.c
> +++ b/tools/bpf/bpftool/map.c
> @@ -1100,6 +1100,7 @@ static int do_create(int argc, char **argv)
> struct bpf_create_map_attr attr = { NULL, };
> const char *pinfile;
> int err, fd;
> + int inner_map_fd = -1;
Nit: reverse-Christmas tree for declaring the variables.
>
> if (!REQ_ARGS(7))
> return -1;
> @@ -1108,48 +1109,75 @@ static int do_create(int argc, char **argv)
> while (argc) {
> if (is_prefix(*argv, "type")) {
> NEXT_ARG();
> - if (!REQ_ARGS(1))
> + if (!REQ_ARGS(1)) {
> + if (inner_map_fd != -1)
> + close(inner_map_fd);
> return -1;
> + }
>
> if (attr.map_type) {
> p_err("map type already specified");
> + if (inner_map_fd != -1)
> + close(inner_map_fd);
> return -1;
> }
>
> attr.map_type = map_type_from_str(*argv);
> if ((int)attr.map_type < 0) {
> p_err("unrecognized map type: %s", *argv);
> + if (inner_map_fd != -1)
> + close(inner_map_fd);
> return -1;
> }
> NEXT_ARG();
> } else if (is_prefix(*argv, "name")) {
> NEXT_ARG();
> - if (!REQ_ARGS(1))
> + if (!REQ_ARGS(1)) {
> + if (inner_map_fd != -1)
> + close(inner_map_fd);
> return -1;
> + }
> attr.name = GET_ARG();
> } else if (is_prefix(*argv, "key")) {
> if (parse_u32_arg(&argc, &argv, &attr.key_size,
> - "key size"))
> + "key size")) {
> + if (inner_map_fd != -1)
> + close(inner_map_fd);
> return -1;
> + }
> } else if (is_prefix(*argv, "value")) {
> if (parse_u32_arg(&argc, &argv, &attr.value_size,
> - "value size"))
> + "value size")) {
> + if (inner_map_fd != -1)
> + close(inner_map_fd);
> return -1;
> + }
> } else if (is_prefix(*argv, "entries")) {
> if (parse_u32_arg(&argc, &argv, &attr.max_entries,
> - "max entries"))
> + "max entries")) {
> + if (inner_map_fd != -1)
> + close(inner_map_fd);
> return -1;
> + }
> } else if (is_prefix(*argv, "flags")) {
> if (parse_u32_arg(&argc, &argv, &attr.map_flags,
> - "flags"))
> + "flags")) {
> + if (inner_map_fd != -1)
> + close(inner_map_fd);
> return -1;
> + }
> } else if (is_prefix(*argv, "dev")) {
> NEXT_ARG();
> - if (!REQ_ARGS(1))
> + if (!REQ_ARGS(1)) {
> + if (inner_map_fd != -1)
> + close(inner_map_fd);
> return -1;
> + }
>
> if (attr.map_ifindex) {
> p_err("offload device already specified");
> + if (inner_map_fd != -1)
> + close(inner_map_fd);
> return -1;
> }
>
> @@ -1157,28 +1185,59 @@ static int do_create(int argc, char **argv)
> if (!attr.map_ifindex) {
> p_err("unrecognized netdevice '%s': %s",
> *argv, strerror(errno));
> + if (inner_map_fd != -1)
> + close(inner_map_fd);
> return -1;
> }
> NEXT_ARG();
> + } else if (is_prefix(*argv, "innermap")) {
> + NEXT_ARG();
> + if (!REQ_ARGS(1)) {
> + if (inner_map_fd != -1)
> + close(inner_map_fd);
> + return -1;
> + }
> +
> + if (inner_map_fd != -1) {
> + close(inner_map_fd);
> + p_err("innermap already specified");
> + return -1;
> + }
> +
> + inner_map_fd = map_parse_fd(&argc, &argv);
> + if (inner_map_fd < 0)
> + return -1;
> } else {
> p_err("unknown arg %s", *argv);
> + if (inner_map_fd != -1)
> + close(inner_map_fd);
> return -1;
> }
> }
>
> if (!attr.name) {
> p_err("map name not specified");
> + if (inner_map_fd != -1)
> + close(inner_map_fd);
> return -1;
> }
>
> set_max_rlimit();
>
> + if (inner_map_fd != -1)
> + attr.inner_map_fd = inner_map_fd;
> +
> fd = bpf_create_map_xattr(&attr);
> if (fd < 0) {
> p_err("map create failed: %s", strerror(errno));
> + if (inner_map_fd != -1)
> + close(inner_map_fd);
> return -1;
You might want to move all those
if (inner_map_fd != -1)
close(inner_map_fd);
return -1;
at the end of the function under a label, and jump there with a goto for
the 15 or so occurrences of the pattern?
> }
>
> + if (inner_map_fd != -1)
> + close(inner_map_fd);
> +
> err = do_pin_fd(fd, pinfile);
> close(fd);
> if (err)
> @@ -1243,7 +1302,7 @@ static int do_help(int argc, char **argv)
> "Usage: %s %s { show | list } [MAP]\n"
> " %s %s create FILE type TYPE key KEY_SIZE value VALUE_SIZE \\\n"
> " entries MAX_ENTRIES name NAME [flags FLAGS] \\\n"
> - " [dev NAME]\n"
> + " [dev NAME] [innermap MAP]\n"
> " %s %s dump MAP\n"
> " %s %s update MAP [key DATA] [value VALUE] [UPDATE_FLAGS]\n"
> " %s %s lookup MAP [key DATA]\n"
>