Kui-Feng Lee says:
====================
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.
Major Changes:
- Add new parameters in bpf_iter_link_info to indicate to go through
all tasks or to go through a specific task.
- Change the implementations of BPF iterators of vma, files, and
tasks to allow going through only the resources of a specific task.
- Provide the arguments of parameterized task iterators in
bpf_link_info.
Differences from v10:
- Check pid_alive() to avoid potential errors.
Differences from v9:
- Fix the boundary check of computing page_shift.
- Rewording the reason of checking and returning the same task.
Differences from v8:
- Fix uninitialized variable.
- Avoid redundant work of getting task from pid.
- Change format string to use %u instead of %d.
- Use the value of page_shift to compute correct offset in
bpf_iter_vm_offset.c.
Differences from v7:
- Travel the tasks of a process through task_group linked list
instead of traveling through the whole namespace.
Differences from v6:
- Add part 5 to make bpftool show the value of parameters.
- Change of wording of show_fdinfo() to show pid or tid instead of
always pid.
- Simplify error handling and naming of test cases.
Differences from v5:
- Use user-space tid/pid terminologies in bpf_iter_link_info and
bpf_link_info.
- Fix reference count
- Merge all variants to one 'u32 pid' in internal structs.
(bpf_iter_aux_info and bpf_iter_seq_task_common)
- Compare the result of get_uprobe_offset() with the implementation
with the vma iterators.
- Implement show_fdinfo.
Differences from v4:
- Remove 'type' from bpf_iter_link_info and bpf_link_info.
v10: https://lore.kernel.org/all/
20220831181039.
2680134-1-kuifeng@fb.com/
v9: https://lore.kernel.org/bpf/
20220829192317.486946-1-kuifeng@fb.com/
v8: https://lore.kernel.org/bpf/
20220829192317.486946-1-kuifeng@fb.com/
v7: https://lore.kernel.org/bpf/
20220826003712.
2810158-1-kuifeng@fb.com/
v6: https://lore.kernel.org/bpf/
20220819220927.
3409575-1-kuifeng@fb.com/
v5: https://lore.kernel.org/bpf/
20220811001654.
1316689-1-kuifeng@fb.com/
v4: https://lore.kernel.org/bpf/
20220809195429.
1043220-1-kuifeng@fb.com/
v3: https://lore.kernel.org/bpf/
20220809063501.667610-1-kuifeng@fb.com/
v2: https://lore.kernel.org/bpf/
20220801232649.
2306614-1-kuifeng@fb.com/
v1: https://lore.kernel.org/bpf/
20220726051713.840431-1-kuifeng@fb.com/
====================
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>