Introduce a macro LIBBPF_DEPRECATED_SINCE(major, minor, message) to prepare the deprecation of two API functions. This macro mark the functions as deprecated when libbpf's version reaches the values passed as an argument. Prepare deprecation for btf__get_from_id() and btf__load(), respectively replaced by btf__load_from_kernel_by_id() and btf__load_into_kernel(), for version 0.6 of the library. References: - https://github.com/libbpf/libbpf/issues/278 - https://github.com/libbpf/libbpf/wiki/Libbpf:-the-road-to-v1.0#btfh-apis Side notes: - Because of the constraints from the preprocessor, we have to write a few lines of macro magic for each version used to prepare deprecation (0.6 for now). - Checkpatch complains about the absence of parentheses around the definition for LIBBPF_DEPRECATED_SINCE, but the compiler profusely complains if we attempt to add them. Signed-off-by: Quentin Monnet <quentin@xxxxxxxxxxxxx> --- tools/lib/bpf/Makefile | 3 +++ tools/lib/bpf/btf.h | 2 ++ tools/lib/bpf/libbpf_common.h | 19 +++++++++++++++++++ 3 files changed, 24 insertions(+) diff --git a/tools/lib/bpf/Makefile b/tools/lib/bpf/Makefile index ec14aa725bb0..095d5dc30d50 100644 --- a/tools/lib/bpf/Makefile +++ b/tools/lib/bpf/Makefile @@ -8,6 +8,7 @@ LIBBPF_VERSION := $(shell \ grep -oE '^LIBBPF_([0-9.]+)' libbpf.map | \ sort -rV | head -n1 | cut -d'_' -f2) LIBBPF_MAJOR_VERSION := $(firstword $(subst ., ,$(LIBBPF_VERSION))) +LIBBPF_MINOR_VERSION := $(firstword $(subst ., ,$(subst $(LIBBPF_MAJOR_VERSION)., ,$(LIBBPF_VERSION)))) MAKEFLAGS += --no-print-directory @@ -86,6 +87,8 @@ override CFLAGS += -Werror -Wall override CFLAGS += $(INCLUDES) override CFLAGS += -fvisibility=hidden override CFLAGS += -D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64 +override CFLAGS += -DLIBBPF_MAJOR_VERSION=$(LIBBPF_MAJOR_VERSION) +override CFLAGS += -DLIBBPF_MINOR_VERSION=$(LIBBPF_MINOR_VERSION) # flags specific for shared library SHLIB_FLAGS := -DSHARED -fPIC diff --git a/tools/lib/bpf/btf.h b/tools/lib/bpf/btf.h index 698afde03c2e..a6039ca66895 100644 --- a/tools/lib/bpf/btf.h +++ b/tools/lib/bpf/btf.h @@ -44,9 +44,11 @@ LIBBPF_API struct btf *btf__parse_elf_split(const char *path, struct btf *base_b LIBBPF_API struct btf *btf__parse_raw(const char *path); LIBBPF_API struct btf *btf__parse_raw_split(const char *path, struct btf *base_btf); LIBBPF_API struct btf *btf__load_from_kernel_by_id(__u32 id); +LIBBPF_DEPRECATED_SINCE(0, 6, "use btf__load_from_kernel_by_id instead") LIBBPF_API int btf__get_from_id(__u32 id, struct btf **btf); LIBBPF_API int btf__finalize_data(struct bpf_object *obj, struct btf *btf); +LIBBPF_DEPRECATED_SINCE(0, 6, "use btf__load_into_kernel instead") LIBBPF_API int btf__load(struct btf *btf); LIBBPF_API int btf__load_into_kernel(struct btf *btf); LIBBPF_API __s32 btf__find_by_name(const struct btf *btf, diff --git a/tools/lib/bpf/libbpf_common.h b/tools/lib/bpf/libbpf_common.h index 947d8bd8a7bb..7218d6156ed7 100644 --- a/tools/lib/bpf/libbpf_common.h +++ b/tools/lib/bpf/libbpf_common.h @@ -17,6 +17,25 @@ #define LIBBPF_DEPRECATED(msg) __attribute__((deprecated(msg))) +#define __LIBBPF_GET_VERSION(major, minor) (((major) << 8) + (minor)) +#define __LIBBPF_CURRENT_VERSION \ + __LIBBPF_GET_VERSION(LIBBPF_MAJOR_VERSION, LIBBPF_MINOR_VERSION) +#define __LIBBPF_CURRENT_VERSION_GEQ(major, minor) \ + (__LIBBPF_CURRENT_VERSION >= __LIBBPF_GET_VERSION(major, minor)) +/* Add checks for other versions below when planning deprecation of API symbols + * with the LIBBPF_DEPRECATED_SINCE macro. + */ +#if __LIBBPF_CURRENT_VERSION_GEQ(0, 6) +#define __LIBBPF_MARK_DEPRECATED_0_6(X) X +#else +#define __LIBBPF_MARK_DEPRECATED_0_6(X) +#endif + +/* Mark a symbol as deprecated when libbpf version is >= {major}.{minor} */ +#define LIBBPF_DEPRECATED_SINCE(major, minor, msg) \ + __LIBBPF_MARK_DEPRECATED_ ## major ## _ ## minor \ + (LIBBPF_DEPRECATED("v" # major "." # minor "+, " msg)) + /* Helper macro to declare and initialize libbpf options struct * * This dance with uninitialized declaration, followed by memset to zero, -- 2.30.2
