On Mon, Aug 1, 2022 at 4:27 PM Kui-Feng Lee <kuifeng@xxxxxx> wrote:
>
> Allow creating an iterator that loops through resources of one task/thread.
>
> People could only create iterators to loop through all resources of
> files, vma, and tasks in the system, even though they were interested
> in only the resources of a specific task or process. Passing the
> additional parameters, people can now create an iterator to go
> through all resources or only the resources of a task.
>
> Signed-off-by: Kui-Feng Lee <kuifeng@xxxxxx>
> ---
> include/linux/bpf.h | 4 ++
> include/uapi/linux/bpf.h | 23 +++++++++
> kernel/bpf/task_iter.c | 93 ++++++++++++++++++++++++++--------
> tools/include/uapi/linux/bpf.h | 23 +++++++++
> 4 files changed, 121 insertions(+), 22 deletions(-)
>
> diff --git a/include/linux/bpf.h b/include/linux/bpf.h
> index 11950029284f..3c26dbfc9cef 100644
> --- a/include/linux/bpf.h
> +++ b/include/linux/bpf.h
> @@ -1718,6 +1718,10 @@ int bpf_obj_get_user(const char __user *pathname, int flags);
>
> struct bpf_iter_aux_info {
> struct bpf_map *map;
> + struct {
> + u32 tid;
> + u8 type;
> + } task;
> };
>
> typedef int (*bpf_iter_attach_target_t)(struct bpf_prog *prog,
> diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
> index ffcbf79a556b..ed5ba501609f 100644
> --- a/include/uapi/linux/bpf.h
> +++ b/include/uapi/linux/bpf.h
> @@ -87,10 +87,33 @@ struct bpf_cgroup_storage_key {
> __u32 attach_type; /* program attach type (enum bpf_attach_type) */
> };
>
> +enum bpf_task_iter_type {
> + BPF_TASK_ITER_ALL = 0,
> + BPF_TASK_ITER_TID,
> +};
> +
> union bpf_iter_link_info {
> struct {
> __u32 map_fd;
> } map;
> + /*
> + * Parameters of task iterators.
> + */
> + struct {
> + __u32 pid_fd;
> + /*
> + * The type of the iterator.
> + *
> + * It can be one of enum bpf_task_iter_type.
> + *
> + * BPF_TASK_ITER_ALL (default)
> + * The iterator iterates over resources of everyprocess.
> + *
> + * BPF_TASK_ITER_TID
> + * You should also set *pid_fd* to iterate over one task.
> + */
> + __u8 type; /* BPF_TASK_ITER_* */
__u8 might be a pain for future extensibility.
big vs little endian will be another potential issue.
Maybe use enum bpf_task_iter_type type; here and
move the comment to enum def ?
Or rename it to '__u32 flags;' ?
