[PATCH bpf-next v9 2/5] bpf: Handle bpf_link_info for the parameterized task BPF iterators.

Kui-Feng Lee
2022-08-31T02:38:40Z

Add new fields to bpf_link_info that users can query it through
bpf_obj_get_info_by_fd().

Signed-off-by: Kui-Feng Lee <kuifeng@fb.com>
Acked-by: Yonghong Song <yhs@fb.com>
---
include/uapi/linux/bpf.h | 4 ++++
kernel/bpf/task_iter.c | 18 ++++++++++++++++++
tools/include/uapi/linux/bpf.h | 4 ++++
3 files changed, 26 insertions(+)

diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index f212a19eda06..088cbc8f6a0c 100644
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h
@@ -6216,6 +6216,10 @@ struct bpf_link_info {
__u64 cgroup_id;
__u32 order;
} cgroup;
+ struct {
+ __u32 tid;
+ __u32 pid;
+ } task;
};
} iter;
struct {
diff --git a/kernel/bpf/task_iter.c b/kernel/bpf/task_iter.c
index 93779a021697..14e0b1993738 100644
--- a/kernel/bpf/task_iter.c
+++ b/kernel/bpf/task_iter.c
@@ -675,6 +675,21 @@ static const struct bpf_iter_seq_info task_seq_info = {
.seq_priv_size = sizeof(struct bpf_iter_seq_task_info),
};

+static int bpf_iter_fill_link_info(const struct bpf_iter_aux_info *aux, struct bpf_link_info *info)
+{
+ switch (aux->task.type) {
+ case BPF_TASK_ITER_TID:
+ info->iter.task.tid = aux->task.pid;
+ break;
+ case BPF_TASK_ITER_TGID:
+ info->iter.task.pid = aux->task.pid;
+ break;
+ default:
+ break;
+ }
+ return 0;
+}
+
static struct bpf_iter_reg task_reg_info = {
.target = "task",
.attach_target = bpf_iter_attach_task,
@@ -685,6 +700,7 @@ static struct bpf_iter_reg task_reg_info = {
PTR_TO_BTF_ID_OR_NULL },
},
.seq_info = &task_seq_info,
+ .fill_link_info = bpf_iter_fill_link_info,
};

static const struct bpf_iter_seq_info task_file_seq_info = {
@@ -706,6 +722,7 @@ static struct bpf_iter_reg task_file_reg_info = {
PTR_TO_BTF_ID_OR_NULL },
},
.seq_info = &task_file_seq_info,
+ .fill_link_info = bpf_iter_fill_link_info,
};

static const struct bpf_iter_seq_info task_vma_seq_info = {
@@ -727,6 +744,7 @@ static struct bpf_iter_reg task_vma_reg_info = {
PTR_TO_BTF_ID_OR_NULL },
},
.seq_info = &task_vma_seq_info,
+ .fill_link_info = bpf_iter_fill_link_info,
};

BPF_CALL_5(bpf_find_vma, struct task_struct *, task, u64, start,
diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h
index 40935278eede..864cf6a613d6 100644
--- a/tools/include/uapi/linux/bpf.h
+++ b/tools/include/uapi/linux/bpf.h
@@ -6216,6 +6216,10 @@ struct bpf_link_info {
__u64 cgroup_id;
__u32 order;
} cgroup;
+ struct {
+ __u32 tid;
+ __u32 pid;
+ } task;
};
} iter;
struct {
--
2.30.2