libbpf: Introduce more granular state for bpf_object

We are going to split bpf_object loading into 2 stages: preparation and
loading. This will increase flexibility when working with bpf_object
and unlock some optimizations and use cases.
This patch substitutes a boolean flag (loaded) by more finely-grained
state for bpf_object.

Signed-off-by: Mykyta Yatsenko <yatsenko@meta.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20250303135752.158343-3-mykyta.yatsenko5@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index 4895c7ae64226b4b60644f79adad69c2d9a3c299..7210278ecdcfe82fb1b55cdf75c70bc0fe232bd8 100644 (file)
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -670,11 +670,18 @@ struct elf_state {
 
 struct usdt_manager;
 
+enum bpf_object_state {
+       OBJ_OPEN,
+       OBJ_PREPARED,
+       OBJ_LOADED,
+};
+
 struct bpf_object {
        char name[BPF_OBJ_NAME_LEN];
        char license[64];
        __u32 kern_version;
 
+       enum bpf_object_state state;
        struct bpf_program *programs;
        size_t nr_programs;
        struct bpf_map *maps;
@@ -686,7 +693,6 @@ struct bpf_object {
        int nr_extern;
        int kconfig_map_idx;
 
-       bool loaded;
        bool has_subcalls;
        bool has_rodata;
 
@@ -1511,7 +1517,7 @@ static struct bpf_object *bpf_object__new(const char *path,
        obj->kconfig_map_idx = -1;
 
        obj->kern_version = get_kernel_version();
-       obj->loaded = false;
+       obj->state  = OBJ_OPEN;
 
        return obj;
 }
@@ -4847,7 +4853,7 @@ static int bpf_get_map_info_from_fdinfo(int fd, struct bpf_map_info *info)
 
 static bool map_is_created(const struct bpf_map *map)
 {
-       return map->obj->loaded || map->reused;
+       return map->obj->state >= OBJ_PREPARED || map->reused;
 }
 
 bool bpf_map__autocreate(const struct bpf_map *map)
@@ -8550,7 +8556,7 @@ static int bpf_object_load(struct bpf_object *obj, int extra_log_level, const ch
        if (!obj)
                return libbpf_err(-EINVAL);
 
-       if (obj->loaded) {
+       if (obj->state >= OBJ_LOADED) {
                pr_warn("object '%s': load can't be attempted twice\n", obj->name);
                return libbpf_err(-EINVAL);
        }
@@ -8602,8 +8608,7 @@ static int bpf_object_load(struct bpf_object *obj, int extra_log_level, const ch
        btf__free(obj->btf_vmlinux);
        obj->btf_vmlinux = NULL;
 
-       obj->loaded = true; /* doesn't matter if successfully or not */
-
+       obj->state = OBJ_LOADED; /* doesn't matter if successfully or not */
        if (err)
                goto out;
 
@@ -8866,7 +8871,7 @@ int bpf_object__pin_maps(struct bpf_object *obj, const char *path)
        if (!obj)
                return libbpf_err(-ENOENT);
 
-       if (!obj->loaded) {
+       if (obj->state < OBJ_PREPARED) {
                pr_warn("object not yet loaded; load it first\n");
                return libbpf_err(-ENOENT);
        }
@@ -8945,7 +8950,7 @@ int bpf_object__pin_programs(struct bpf_object *obj, const char *path)
        if (!obj)
                return libbpf_err(-ENOENT);
 
-       if (!obj->loaded) {
+       if (obj->state < OBJ_LOADED) {
                pr_warn("object not yet loaded; load it first\n");
                return libbpf_err(-ENOENT);
        }
@@ -9132,7 +9137,7 @@ int bpf_object__btf_fd(const struct bpf_object *obj)
 
 int bpf_object__set_kversion(struct bpf_object *obj, __u32 kern_version)
 {
-       if (obj->loaded)
+       if (obj->state >= OBJ_LOADED)
                return libbpf_err(-EINVAL);
 
        obj->kern_version = kern_version;
@@ -9229,7 +9234,7 @@ bool bpf_program__autoload(const struct bpf_program *prog)
 
 int bpf_program__set_autoload(struct bpf_program *prog, bool autoload)
 {
-       if (prog->obj->loaded)
+       if (prog->obj->state >= OBJ_LOADED)
                return libbpf_err(-EINVAL);
 
        prog->autoload = autoload;
@@ -9261,7 +9266,7 @@ int bpf_program__set_insns(struct bpf_program *prog,
 {
        struct bpf_insn *insns;
 
-       if (prog->obj->loaded)
+       if (prog->obj->state >= OBJ_LOADED)
                return libbpf_err(-EBUSY);
 
        insns = libbpf_reallocarray(prog->insns, new_insn_cnt, sizeof(*insns));
@@ -9304,7 +9309,7 @@ static int last_custom_sec_def_handler_id;
 
 int bpf_program__set_type(struct bpf_program *prog, enum bpf_prog_type type)
 {
-       if (prog->obj->loaded)
+       if (prog->obj->state >= OBJ_LOADED)
                return libbpf_err(-EBUSY);
 
        /* if type is not changed, do nothing */
@@ -9335,7 +9340,7 @@ enum bpf_attach_type bpf_program__expected_attach_type(const struct bpf_program
 int bpf_program__set_expected_attach_type(struct bpf_program *prog,
                                           enum bpf_attach_type type)
 {
-       if (prog->obj->loaded)
+       if (prog->obj->state >= OBJ_LOADED)
                return libbpf_err(-EBUSY);
 
        prog->expected_attach_type = type;
@@ -9349,7 +9354,7 @@ __u32 bpf_program__flags(const struct bpf_program *prog)
 
 int bpf_program__set_flags(struct bpf_program *prog, __u32 flags)
 {
-       if (prog->obj->loaded)
+       if (prog->obj->state >= OBJ_LOADED)
                return libbpf_err(-EBUSY);
 
        prog->prog_flags = flags;
@@ -9363,7 +9368,7 @@ __u32 bpf_program__log_level(const struct bpf_program *prog)
 
 int bpf_program__set_log_level(struct bpf_program *prog, __u32 log_level)
 {
-       if (prog->obj->loaded)
+       if (prog->obj->state >= OBJ_LOADED)
                return libbpf_err(-EBUSY);
 
        prog->log_level = log_level;
@@ -9382,7 +9387,7 @@ int bpf_program__set_log_buf(struct bpf_program *prog, char *log_buf, size_t log
                return libbpf_err(-EINVAL);
        if (prog->log_size > UINT_MAX)
                return libbpf_err(-EINVAL);
-       if (prog->obj->loaded)
+       if (prog->obj->state >= OBJ_LOADED)
                return libbpf_err(-EBUSY);
 
        prog->log_buf = log_buf;
@@ -13666,7 +13671,7 @@ int bpf_program__set_attach_target(struct bpf_program *prog,
        if (!prog || attach_prog_fd < 0)
                return libbpf_err(-EINVAL);
 
-       if (prog->obj->loaded)
+       if (prog->obj->state >= OBJ_LOADED)
                return libbpf_err(-EINVAL);
 
        if (attach_prog_fd && !attach_func_name) {