libbpf: Add helper macro to clear opts structs

Add a small and generic LIBBPF_OPTS_RESET() helper macros which clears an
opts structure and reinitializes its .sz member to place the structure
size. Additionally, the user can pass option-specific data to reinitialize
via varargs.

I found this very useful when developing selftests, but it is also generic
enough as a macro next to the existing LIBBPF_OPTS() which hides the .sz
initialization, too.

Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/r/20230719140858.13224-6-daniel@iogearbox.net
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This commit is contained in:
Daniel Borkmann 2023-07-19 16:08:55 +02:00 committed by Alexei Starovoitov
parent 55cc376847
commit 4e9c2d9af5

View File

@ -70,4 +70,20 @@
}; \
})
/* Helper macro to clear and optionally reinitialize libbpf options struct
*
* Small helper macro to reset all fields and to reinitialize the common
* structure size member. Values provided by users in struct initializer-
* syntax as varargs can be provided as well to reinitialize options struct
* specific members.
*/
#define LIBBPF_OPTS_RESET(NAME, ...) \
do { \
memset(&NAME, 0, sizeof(NAME)); \
NAME = (typeof(NAME)) { \
.sz = sizeof(NAME), \
__VA_ARGS__ \
}; \
} while (0)
#endif /* __LIBBPF_LIBBPF_COMMON_H */