[PATCH bpf-next v1] tools/bpftool: create map of maps

[Alban Crequy]

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>
---
 tools/bpf/bpftool/Documentation/bpftool-prog.rst |  2 +-
 tools/bpf/bpftool/bash-completion/bpftool        | 13 +++++++++++++
 tools/bpf/bpftool/map.c                          |  5 ++++-
 3 files changed, 18 insertions(+), 2 deletions(-)

diff --git a/tools/bpf/bpftool/Documentation/bpftool-prog.rst b/tools/bpf/bpftool/Documentation/bpftool-prog.rst
index 9386bd6e0396..35902ab95cc5 100644
--- a/tools/bpf/bpftool/Documentation/bpftool-prog.rst
+++ b/tools/bpf/bpftool/Documentation/bpftool-prog.rst
@@ -25,7 +25,7 @@ PROG COMMANDS
 |	**bpftool** **prog dump xlated** *PROG* [{**file** *FILE* | **opcodes** | **visual** | **linum**}]
 |	**bpftool** **prog dump jited**  *PROG* [{**file** *FILE* | **opcodes** | **linum**}]
 |	**bpftool** **prog pin** *PROG* *FILE*
-|	**bpftool** **prog { load | loadall }** *OBJ* *PATH* [**type** *TYPE*] [**map** {**idx** *IDX* | **name** *NAME*} *MAP*] [**dev** *NAME*]
+|	**bpftool** **prog { load | loadall }** *OBJ* *PATH* [**type** *TYPE*] [**map** {**idx** *IDX* | **name** *NAME*} *MAP*] [**dev** *NAME*] [**innermap** MAP]
 |	**bpftool** **prog attach** *PROG* *ATTACH_TYPE* [*MAP*]
 |	**bpftool** **prog detach** *PROG* *ATTACH_TYPE* [*MAP*]
 |	**bpftool** **prog tracelog**
diff --git a/tools/bpf/bpftool/bash-completion/bpftool b/tools/bpf/bpftool/bash-completion/bpftool
index b803827d01e8..dcdc39510dc3 100644
--- a/tools/bpf/bpftool/bash-completion/bpftool
+++ b/tools/bpf/bpftool/bash-completion/bpftool
@@ -461,6 +461,18 @@ _bpftool()
                             _sysfs_get_netdevs
                             return 0
                             ;;
+                        innermap)
+                            COMPREPLY+=( $( compgen -W "id pinned" -- "$cur" ) )
+                            return 0
+                            ;;
+                        id)
+                            _bpftool_get_map_ids
+                            return 0
+                            ;;
+                        pinned)
+                            _filedir
+                            return 0
+                            ;;
                         *)
                             _bpftool_once_attr 'type'
                             _bpftool_once_attr 'key'
@@ -469,6 +481,7 @@ _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 e0c650d91784..7d8ce903a471 100644
--- a/tools/bpf/bpftool/map.c
+++ b/tools/bpf/bpftool/map.c
@@ -1151,6 +1151,9 @@ static int do_create(int argc, char **argv)
 				return -1;
 			}
 			NEXT_ARG();
+		} else if (is_prefix(*argv, "innermap")) {
+			NEXT_ARG();
+			attr.inner_map_fd = map_parse_fd(&argc, &argv);
 		}
 	}
 
@@ -1231,7 +1234,7 @@ 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"
-- 
2.20.1