libbpf: Simplify BPF program auto-attach code

Remove the need to explicitly pass bpf_sec_def for auto-attachable BPF
programs, as it is already recorded at bpf_object__open() time for all
recognized type of BPF programs. This further reduces number of explicit
calls to find_sec_def(), simplifying further refactorings.

No functional changes are done by this patch.

Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Link: https://lore.kernel.org/bpf/20210914014733.2768-4-andrii@kernel.org

diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index 6abfbf2..e473fbd 100644 (file)
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -218,8 +218,7 @@ struct reloc_desc {
 
 struct bpf_sec_def;
 
-typedef struct bpf_link *(*attach_fn_t)(const struct bpf_sec_def *sec,
-                                       struct bpf_program *prog);
+typedef struct bpf_link *(*attach_fn_t)(struct bpf_program *prog);
 
 struct bpf_sec_def {
        const char *sec;
@@ -7920,18 +7919,12 @@ void bpf_program__set_expected_attach_type(struct bpf_program *prog,
        __VA_ARGS__                                                         \
 }
 
-static struct bpf_link *attach_kprobe(const struct bpf_sec_def *sec,
-                                     struct bpf_program *prog);
-static struct bpf_link *attach_tp(const struct bpf_sec_def *sec,
-                                 struct bpf_program *prog);
-static struct bpf_link *attach_raw_tp(const struct bpf_sec_def *sec,
-                                     struct bpf_program *prog);
-static struct bpf_link *attach_trace(const struct bpf_sec_def *sec,
-                                    struct bpf_program *prog);
-static struct bpf_link *attach_lsm(const struct bpf_sec_def *sec,
-                                  struct bpf_program *prog);
-static struct bpf_link *attach_iter(const struct bpf_sec_def *sec,
-                                   struct bpf_program *prog);
+static struct bpf_link *attach_kprobe(struct bpf_program *prog);
+static struct bpf_link *attach_tp(struct bpf_program *prog);
+static struct bpf_link *attach_raw_tp(struct bpf_program *prog);
+static struct bpf_link *attach_trace(struct bpf_program *prog);
+static struct bpf_link *attach_lsm(struct bpf_program *prog);
+static struct bpf_link *attach_iter(struct bpf_program *prog);
 
 static const struct bpf_sec_def section_defs[] = {
        BPF_PROG_SEC("socket",                  BPF_PROG_TYPE_SOCKET_FILTER),
@@ -9391,8 +9384,7 @@ struct bpf_link *bpf_program__attach_kprobe(struct bpf_program *prog,
        return bpf_program__attach_kprobe_opts(prog, func_name, &opts);
 }
 
-static struct bpf_link *attach_kprobe(const struct bpf_sec_def *sec,
-                                     struct bpf_program *prog)
+static struct bpf_link *attach_kprobe(struct bpf_program *prog)
 {
        DECLARE_LIBBPF_OPTS(bpf_kprobe_opts, opts);
        unsigned long offset = 0;
@@ -9401,8 +9393,8 @@ static struct bpf_link *attach_kprobe(const struct bpf_sec_def *sec,
        char *func;
        int n, err;
 
-       func_name = prog->sec_name + sec->len;
-       opts.retprobe = strcmp(sec->sec, "kretprobe/") == 0;
+       func_name = prog->sec_name + prog->sec_def->len;
+       opts.retprobe = strcmp(prog->sec_def->sec, "kretprobe/") == 0;
 
        n = sscanf(func_name, "%m[a-zA-Z0-9_.]+%li", &func, &offset);
        if (n < 1) {
@@ -9565,8 +9557,7 @@ struct bpf_link *bpf_program__attach_tracepoint(struct bpf_program *prog,
        return bpf_program__attach_tracepoint_opts(prog, tp_category, tp_name, NULL);
 }
 
-static struct bpf_link *attach_tp(const struct bpf_sec_def *sec,
-                                 struct bpf_program *prog)
+static struct bpf_link *attach_tp(struct bpf_program *prog)
 {
        char *sec_name, *tp_cat, *tp_name;
        struct bpf_link *link;
@@ -9576,7 +9567,7 @@ static struct bpf_link *attach_tp(const struct bpf_sec_def *sec,
                return libbpf_err_ptr(-ENOMEM);
 
        /* extract "tp/<category>/<name>" */
-       tp_cat = sec_name + sec->len;
+       tp_cat = sec_name + prog->sec_def->len;
        tp_name = strchr(tp_cat, '/');
        if (!tp_name) {
                free(sec_name);
@@ -9620,10 +9611,9 @@ struct bpf_link *bpf_program__attach_raw_tracepoint(struct bpf_program *prog,
        return link;
 }
 
-static struct bpf_link *attach_raw_tp(const struct bpf_sec_def *sec,
-                                     struct bpf_program *prog)
+static struct bpf_link *attach_raw_tp(struct bpf_program *prog)
 {
-       const char *tp_name = prog->sec_name + sec->len;
+       const char *tp_name = prog->sec_name + prog->sec_def->len;
 
        return bpf_program__attach_raw_tracepoint(prog, tp_name);
 }
@@ -9668,14 +9658,12 @@ struct bpf_link *bpf_program__attach_lsm(struct bpf_program *prog)
        return bpf_program__attach_btf_id(prog);
 }
 
-static struct bpf_link *attach_trace(const struct bpf_sec_def *sec,
-                                    struct bpf_program *prog)
+static struct bpf_link *attach_trace(struct bpf_program *prog)
 {
        return bpf_program__attach_trace(prog);
 }
 
-static struct bpf_link *attach_lsm(const struct bpf_sec_def *sec,
-                                  struct bpf_program *prog)
+static struct bpf_link *attach_lsm(struct bpf_program *prog)
 {
        return bpf_program__attach_lsm(prog);
 }
@@ -9806,21 +9794,17 @@ bpf_program__attach_iter(struct bpf_program *prog,
        return link;
 }
 
-static struct bpf_link *attach_iter(const struct bpf_sec_def *sec,
-                                   struct bpf_program *prog)
+static struct bpf_link *attach_iter(struct bpf_program *prog)
 {
        return bpf_program__attach_iter(prog, NULL);
 }
 
 struct bpf_link *bpf_program__attach(struct bpf_program *prog)
 {
-       const struct bpf_sec_def *sec_def;
-
-       sec_def = find_sec_def(prog->sec_name);
-       if (!sec_def || !sec_def->attach_fn)
+       if (!prog->sec_def || !prog->sec_def->attach_fn)
                return libbpf_err_ptr(-ESRCH);
 
-       return sec_def->attach_fn(sec_def, prog);
+       return prog->sec_def->attach_fn(prog);
 }
 
 static int bpf_link__detach_struct_ops(struct bpf_link *link)
@@ -10899,16 +10883,15 @@ int bpf_object__attach_skeleton(struct bpf_object_skeleton *s)
        for (i = 0; i < s->prog_cnt; i++) {
                struct bpf_program *prog = *s->progs[i].prog;
                struct bpf_link **link = s->progs[i].link;
-               const struct bpf_sec_def *sec_def;
 
                if (!prog->load)
                        continue;
 
-               sec_def = find_sec_def(prog->sec_name);
-               if (!sec_def || !sec_def->attach_fn)
+               /* auto-attaching not supported for this program */
+               if (!prog->sec_def || !prog->sec_def->attach_fn)
                        continue;
 
-               *link = sec_def->attach_fn(sec_def, prog);
+               *link = prog->sec_def->attach_fn(prog);
                err = libbpf_get_error(*link);
                if (err) {
                        pr_warn("failed to auto-attach program '%s': %d\n",