Commit a7db0d4f authored by Kui-Feng Lee's avatar Kui-Feng Lee Committed by Alexei Starovoitov
Browse files

bpf: refactor btf_find_struct_field() and btf_find_datasec_var(). 



Move common code of the two functions to btf_find_field_one().

Acked-by: default avatarEduard Zingerman <eddyz87@gmail.com>
Signed-off-by: default avatarKui-Feng Lee <thinker.li@gmail.com>
Link: https://lore.kernel.org/r/20240523174202.461236-4-thinker.li@gmail.com


Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
parent 482f7133

kernel/bpf/btf.c

+79 −101
Original line number Diff line number Diff line
@@ -3494,33 +3494,28 @@ static int btf_get_field_type(const char *name, u32 field_mask, u32 *seen_mask, 


#undef field_mask_test_name



static int btf_find_struct_field(const struct btf *btf,

				 const struct btf_type *t, u32 field_mask,

static int btf_find_field_one(const struct btf *btf,

			      const struct btf_type *var,

			      const struct btf_type *var_type,

			      int var_idx,

			      u32 off, u32 expected_size,

			      u32 field_mask, u32 *seen_mask,

			      struct btf_field_info *info, int info_cnt)

{

	int ret, idx = 0, align, sz, field_type;

	const struct btf_member *member;

	int ret, align, sz, field_type;

	struct btf_field_info tmp;

	u32 i, off, seen_mask = 0;



	for_each_member(i, t, member) {

		const struct btf_type *member_type = btf_type_by_id(btf,

								    member->type);



		field_type = btf_get_field_type(__btf_name_by_offset(btf, member_type->name_off),

						field_mask, &seen_mask, &align, &sz);

	field_type = btf_get_field_type(__btf_name_by_offset(btf, var_type->name_off),

					field_mask, seen_mask, &align, &sz);

	if (field_type == 0)

			continue;

		return 0;

	if (field_type < 0)

		return field_type;



		off = __btf_member_bit_offset(t, member);

		if (off % 8)

			/* valid C code cannot generate such BTF */

			return -EINVAL;

		off /= 8;

	if (expected_size && expected_size != sz)

		return 0;

	if (off % align)

			continue;

		return 0;



	switch (field_type) {

	case BPF_SPIN_LOCK:
@@ -3529,24 +3524,24 @@ static int btf_find_struct_field(const struct btf *btf, 
	case BPF_LIST_NODE:

	case BPF_RB_NODE:

	case BPF_REFCOUNT:

			ret = btf_find_struct(btf, member_type, off, sz, field_type,

					      idx < info_cnt ? &info[idx] : &tmp);

		ret = btf_find_struct(btf, var_type, off, sz, field_type,

				      info_cnt ? &info[0] : &tmp);

		if (ret < 0)

			return ret;

		break;

	case BPF_KPTR_UNREF:

	case BPF_KPTR_REF:

	case BPF_KPTR_PERCPU:

			ret = btf_find_kptr(btf, member_type, off, sz,

					    idx < info_cnt ? &info[idx] : &tmp);

		ret = btf_find_kptr(btf, var_type, off, sz,

				    info_cnt ? &info[0] : &tmp);

		if (ret < 0)

			return ret;

		break;

	case BPF_LIST_HEAD:

	case BPF_RB_ROOT:

			ret = btf_find_graph_root(btf, t, member_type,

						  i, off, sz,

						  idx < info_cnt ? &info[idx] : &tmp,

		ret = btf_find_graph_root(btf, var, var_type,

					  var_idx, off, sz,

					  info_cnt ? &info[0] : &tmp,

					  field_type);

		if (ret < 0)

			return ret;
@@ -3556,10 +3551,38 @@ static int btf_find_struct_field(const struct btf *btf, 
	}



	if (ret == BTF_FIELD_IGNORE)

			continue;

		if (idx >= info_cnt)

		return 0;

	if (!info_cnt)

		return -E2BIG;

		++idx;



	return 1;

}



static int btf_find_struct_field(const struct btf *btf,

				 const struct btf_type *t, u32 field_mask,

				 struct btf_field_info *info, int info_cnt)

{

	int ret, idx = 0;

	const struct btf_member *member;

	u32 i, off, seen_mask = 0;



	for_each_member(i, t, member) {

		const struct btf_type *member_type = btf_type_by_id(btf,

								    member->type);



		off = __btf_member_bit_offset(t, member);

		if (off % 8)

			/* valid C code cannot generate such BTF */

			return -EINVAL;

		off /= 8;



		ret = btf_find_field_one(btf, t, member_type, i,

					 off, 0,

					 field_mask, &seen_mask,

					 &info[idx], info_cnt - idx);

		if (ret < 0)

			return ret;

		idx += ret;

	}

	return idx;

}
@@ -3568,66 +3591,21 @@ static int btf_find_datasec_var(const struct btf *btf, const struct btf_type *t, 
				u32 field_mask, struct btf_field_info *info,

				int info_cnt)

{

	int ret, idx = 0, align, sz, field_type;

	int ret, idx = 0;

	const struct btf_var_secinfo *vsi;

	struct btf_field_info tmp;

	u32 i, off, seen_mask = 0;



	for_each_vsi(i, t, vsi) {

		const struct btf_type *var = btf_type_by_id(btf, vsi->type);

		const struct btf_type *var_type = btf_type_by_id(btf, var->type);



		field_type = btf_get_field_type(__btf_name_by_offset(btf, var_type->name_off),

						field_mask, &seen_mask, &align, &sz);

		if (field_type == 0)

			continue;

		if (field_type < 0)

			return field_type;



		off = vsi->offset;

		if (vsi->size != sz)

			continue;

		if (off % align)

			continue;



		switch (field_type) {

		case BPF_SPIN_LOCK:

		case BPF_TIMER:

		case BPF_WORKQUEUE:

		case BPF_LIST_NODE:

		case BPF_RB_NODE:

		case BPF_REFCOUNT:

			ret = btf_find_struct(btf, var_type, off, sz, field_type,

					      idx < info_cnt ? &info[idx] : &tmp);

		ret = btf_find_field_one(btf, var, var_type, -1, off, vsi->size,

					 field_mask, &seen_mask,

					 &info[idx], info_cnt - idx);

		if (ret < 0)

			return ret;

			break;

		case BPF_KPTR_UNREF:

		case BPF_KPTR_REF:

		case BPF_KPTR_PERCPU:

			ret = btf_find_kptr(btf, var_type, off, sz,

					    idx < info_cnt ? &info[idx] : &tmp);

			if (ret < 0)

				return ret;

			break;

		case BPF_LIST_HEAD:

		case BPF_RB_ROOT:

			ret = btf_find_graph_root(btf, var, var_type,

						  -1, off, sz,

						  idx < info_cnt ? &info[idx] : &tmp,

						  field_type);

			if (ret < 0)

				return ret;

			break;

		default:

			return -EFAULT;

		}



		if (ret == BTF_FIELD_IGNORE)

			continue;

		if (idx >= info_cnt)

			return -E2BIG;

		++idx;

		idx += ret;

	}

	return idx;

}