Return result of btf_get_prog_ctx_type() is never used and callers only
check NULL vs non-NULL case to determine if given type matches expected
PTR_TO_CTX type. So rename function to `btf_is_prog_ctx_type()` and
return a simple true/false. We'll use this simpler interface to handle
kprobe program type's special typedef case in the next patch.
Signed-off-by: Andrii Nakryiko <andrii@xxxxxxxxxx>
---
include/linux/btf.h | 17 ++++++++---------
kernel/bpf/btf.c | 27 +++++++++++++--------------
kernel/bpf/verifier.c | 2 +-
3 files changed, 22 insertions(+), 24 deletions(-)
diff --git a/include/linux/btf.h b/include/linux/btf.h
index 1ee8977b8c95..7cfccd7a851d 100644
--- a/include/linux/btf.h
+++ b/include/linux/btf.h
@@ -525,10 +525,9 @@ s32 btf_find_dtor_kfunc(struct btf *btf, u32 btf_id);
int register_btf_id_dtor_kfuncs(const struct btf_id_dtor_kfunc *dtors, u32 add_cnt,
struct module *owner);
struct btf_struct_meta *btf_find_struct_meta(const struct btf *btf, u32 btf_id);
-const struct btf_type *
-btf_get_prog_ctx_type(struct bpf_verifier_log *log, const struct btf *btf,
- const struct btf_type *t, enum bpf_prog_type prog_type,
- int arg);
+bool btf_is_prog_ctx_type(struct bpf_verifier_log *log, const struct btf *btf,
+ const struct btf_type *t, enum bpf_prog_type prog_type,
+ int arg);
int get_kern_ctx_btf_id(struct bpf_verifier_log *log, enum bpf_prog_type prog_type);
bool btf_types_are_same(const struct btf *btf1, u32 id1,
const struct btf *btf2, u32 id2);
@@ -568,12 +567,12 @@ static inline struct btf_struct_meta *btf_find_struct_meta(const struct btf *btf
{
return NULL;
}
-static inline const struct btf_member *
-btf_get_prog_ctx_type(struct bpf_verifier_log *log, const struct btf *btf,
- const struct btf_type *t, enum bpf_prog_type prog_type,
- int arg)
+static inline bool
+btf_is_prog_ctx_type(struct bpf_verifier_log *log, const struct btf *btf,
+ const struct btf_type *t, enum bpf_prog_type prog_type,
+ int arg)
{
- return NULL;
+ return false;
}
static inline int get_kern_ctx_btf_id(struct bpf_verifier_log *log,
enum bpf_prog_type prog_type) {
diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c
index 8e06d29961f1..f0ce384aa73e 100644
--- a/kernel/bpf/btf.c
+++ b/kernel/bpf/btf.c
@@ -5687,10 +5687,9 @@ static int find_kern_ctx_type_id(enum bpf_prog_type prog_type)
return ctx_type->type;
}
-const struct btf_type *
-btf_get_prog_ctx_type(struct bpf_verifier_log *log, const struct btf *btf,
- const struct btf_type *t, enum bpf_prog_type prog_type,
- int arg)
+bool btf_is_prog_ctx_type(struct bpf_verifier_log *log, const struct btf *btf,
+ const struct btf_type *t, enum bpf_prog_type prog_type,
+ int arg)
{
const struct btf_type *ctx_type;
const char *tname, *ctx_tname;
@@ -5704,26 +5703,26 @@ btf_get_prog_ctx_type(struct bpf_verifier_log *log, const struct btf *btf,
* is not supported yet.
* BPF_PROG_TYPE_RAW_TRACEPOINT is fine.
*/
- return NULL;
+ return false;
}
tname = btf_name_by_offset(btf, t->name_off);
if (!tname) {
bpf_log(log, "arg#%d struct doesn't have a name\n", arg);
- return NULL;
+ return false;
}
ctx_type = find_canonical_prog_ctx_type(prog_type);
if (!ctx_type) {
bpf_log(log, "btf_vmlinux is malformed\n");
/* should not happen */
- return NULL;
+ return false;
}
again:
ctx_tname = btf_name_by_offset(btf_vmlinux, ctx_type->name_off);
if (!ctx_tname) {
/* should not happen */
bpf_log(log, "Please fix kernel include/linux/bpf_types.h\n");
- return NULL;
+ return false;
}
/* only compare that prog's ctx type name is the same as
* kernel expects. No need to compare field by field.
@@ -5733,20 +5732,20 @@ btf_get_prog_ctx_type(struct bpf_verifier_log *log, const struct btf *btf,
* { // no fields of skb are ever used }
*/
if (strcmp(ctx_tname, "__sk_buff") == 0 && strcmp(tname, "sk_buff") == 0)
- return ctx_type;
+ return true;
if (strcmp(ctx_tname, "xdp_md") == 0 && strcmp(tname, "xdp_buff") == 0)
- return ctx_type;
+ return true;
if (strcmp(ctx_tname, tname)) {
/* bpf_user_pt_regs_t is a typedef, so resolve it to
* underlying struct and check name again
*/
if (!btf_type_is_modifier(ctx_type))
- return NULL;
+ return false;
while (btf_type_is_modifier(ctx_type))
ctx_type = btf_type_by_id(btf_vmlinux, ctx_type->type);
goto again;
}
- return ctx_type;
+ return true;
}
/* forward declarations for arch-specific underlying types of
@@ -5898,7 +5897,7 @@ static int btf_translate_to_vmlinux(struct bpf_verifier_log *log,
enum bpf_prog_type prog_type,
int arg)
{
- if (!btf_get_prog_ctx_type(log, btf, t, prog_type, arg))
+ if (!btf_is_prog_ctx_type(log, btf, t, prog_type, arg))
return -ENOENT;
return find_kern_ctx_type_id(prog_type);
}
@@ -7184,7 +7183,7 @@ int btf_prepare_func_args(struct bpf_verifier_env *env, int subprog)
if (!btf_type_is_ptr(t))
goto skip_pointer;
- if ((tags & ARG_TAG_CTX) || btf_get_prog_ctx_type(log, btf, t, prog_type, i)) {
+ if ((tags & ARG_TAG_CTX) || btf_is_prog_ctx_type(log, btf, t, prog_type, i)) {
if (tags & ~ARG_TAG_CTX) {
bpf_log(log, "arg#%d has invalid combination of tags\n", i);
return -EINVAL;
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index ddaf09db1175..0a6e047e4ee4 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -11033,7 +11033,7 @@ get_kfunc_ptr_arg_type(struct bpf_verifier_env *env,
* type to our caller. When a set of conditions hold in the BTF type of
* arguments, we resolve it to a known kfunc_ptr_arg_type.
*/
- if (btf_get_prog_ctx_type(&env->log, meta->btf, t, resolve_prog_type(env->prog), argno))
+ if (btf_is_prog_ctx_type(&env->log, meta->btf, t, resolve_prog_type(env->prog), argno))
return KF_ARG_PTR_TO_CTX;
if (is_kfunc_arg_alloc_obj(meta->btf, &args[argno]))
--
2.39.3
