Commit f3c45326 authored by Joe Stringer's avatar Joe Stringer Committed by Daniel Borkmann
Browse files

bpf: Document PROG_TEST_RUN limitations 



Per net/bpf/test_run.c, particular prog types have additional
restrictions around the parameters that can be provided, so document
these in the header.

I didn't bother documenting the limitation on duration for raw
tracepoints since that's an output parameter anyway.

Tested with ./tools/testing/selftests/bpf/test_doc_build.sh.

Suggested-by: default avatarYonghong Song <yhs@fb.com>
Signed-off-by: default avatarJoe Stringer <joe@cilium.io>
Signed-off-by: default avatarDaniel Borkmann <daniel@iogearbox.net>
Acked-by: default avatarYonghong Song <yhs@fb.com>
Acked-by: default avatarLorenz Bauer <lmb@cloudflare.com>
Link: https://lore.kernel.org/bpf/20210410174549.816482-1-joe@cilium.io
parent 92d3bff2

include/uapi/linux/bpf.h

+21 −0
Original line number Diff line number Diff line
@@ -312,6 +312,27 @@ union bpf_iter_link_info { 
 *		*ctx_out*, *data_out* (for example, packet data), result of the

 *		execution *retval*, and *duration* of the test run.

 *

 *		The sizes of the buffers provided as input and output

 *		parameters *ctx_in*, *ctx_out*, *data_in*, and *data_out* must

 *		be provided in the corresponding variables *ctx_size_in*,

 *		*ctx_size_out*, *data_size_in*, and/or *data_size_out*. If any

 *		of these parameters are not provided (ie set to NULL), the

 *		corresponding size field must be zero.

 *

 *		Some program types have particular requirements:

 *

 *		**BPF_PROG_TYPE_SK_LOOKUP**

 *			*data_in* and *data_out* must be NULL.

 *

 *		**BPF_PROG_TYPE_XDP**

 *			*ctx_in* and *ctx_out* must be NULL.

 *

 *		**BPF_PROG_TYPE_RAW_TRACEPOINT**,

 *		**BPF_PROG_TYPE_RAW_TRACEPOINT_WRITABLE**

 *

 *			*ctx_out*, *data_in* and *data_out* must be NULL.

 *			*repeat* must be zero.

 *

 *	Return

 *		Returns zero on success. On error, -1 is returned and *errno*

 *		is set appropriately.