tools: bpftool: document restriction on '.' in names to pin in bpffs

Names used to pin eBPF programs and maps under the eBPF virtual file
system cannot contain a dot character, which is reserved for future
extensions of this file system.

Document this in bpftool man pages to avoid users getting confused if
pinning fails because of a dot.

Signed-off-by: Quentin Monnet <quentin.monnet@netronome.com>
Reviewed-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

diff --git a/tools/bpf/bpftool/Documentation/bpftool-map.rst b/tools/bpf/bpftool/Documentation/bpftool-map.rst
index 3497f2d..f55a2da 100644 (file)
--- a/tools/bpf/bpftool/Documentation/bpftool-map.rst
+++ b/tools/bpf/bpftool/Documentation/bpftool-map.rst
@@ -86,7 +86,9 @@ DESCRIPTION
        **bpftool map pin**     *MAP*  *FILE*
                  Pin map *MAP* as *FILE*.
 
-                 Note: *FILE* must be located in *bpffs* mount.
+                 Note: *FILE* must be located in *bpffs* mount. It must not
+                 contain a dot character ('.'), which is reserved for future
+                 extensions of *bpffs*.
 
        **bpftool** **map event_pipe** *MAP* [**cpu** *N* **index** *M*]
                  Read events from a BPF_MAP_TYPE_PERF_EVENT_ARRAY map.

diff --git a/tools/bpf/bpftool/Documentation/bpftool-prog.rst b/tools/bpf/bpftool/Documentation/bpftool-prog.rst
index 12c8030..ac4e904 100644 (file)
--- a/tools/bpf/bpftool/Documentation/bpftool-prog.rst
+++ b/tools/bpf/bpftool/Documentation/bpftool-prog.rst
@@ -75,7 +75,9 @@ DESCRIPTION
        **bpftool prog pin** *PROG* *FILE*
                  Pin program *PROG* as *FILE*.
 
-                 Note: *FILE* must be located in *bpffs* mount.
+                 Note: *FILE* must be located in *bpffs* mount. It must not
+                 contain a dot character ('.'), which is reserved for future
+                 extensions of *bpffs*.
 
        **bpftool prog load** *OBJ* *FILE* [**type** *TYPE*] [**map** {**idx** *IDX* | **name** *NAME*} *MAP*] [**dev** *NAME*]
                  Load bpf program from binary *OBJ* and pin as *FILE*.
@@ -91,7 +93,9 @@ DESCRIPTION
                  If **dev** *NAME* is specified program will be loaded onto
                  given networking device (offload).
 
-                 Note: *FILE* must be located in *bpffs* mount.
+                 Note: *FILE* must be located in *bpffs* mount. It must not
+                 contain a dot character ('.'), which is reserved for future
+                 extensions of *bpffs*.
 
         **bpftool prog attach** *PROG* *ATTACH_TYPE* *MAP*
                   Attach bpf program *PROG* (with type specified by *ATTACH_TYPE*)