Merge branch 'bpf-add-_impl-suffix-for-kfuncs-with-implicit-args'

Mykyta Yatsenko says:

====================
bpf: Add _impl suffix for kfuncs with implicit args

We have established a pattern of function naming win "_impl" suffix;
those functions accept verifier-provided bpf_prog_aux argument.
Following uniform convention will allow for transparent backwards
compatibility with the upcoming KF_IMPLICIT_ARGS feature. This patch
set aims to fix current deviation from the convention to eliminate
unnecessary backwards incompatibility in the future.

Three kfuncs added in 6.18 don’t follow this *_impl convention and
therefore won’t participate in the new KF_IMPLICIT_ARGS mechanism:
 * bpf_task_work_schedule_resume()
 * bpf_task_work_schedule_signal()
 * bpf_stream_vprintk()

Rename them to align with the implicit-arg flow:
bpf_task_work_schedule_resume() -> bpf_task_work_schedule_resume_impl()
bpf_task_work_schedule_signal() -> bpf_task_work_schedule_signal_impl()
bpf_stream_vprintk() -> bpf_stream_vprintk_impl()

The KF_IMPLICIT_ARGS mechanism is not in tree yet, so callers must
switch to the *_impl names for now. Once the new mechanism lands, the
plain names (without _impl) will be reintroduced.

Signed-off-by: Mykyta Yatsenko <yatsenko@meta.com>
Acked-by: Ihor Solodrai <ihor.solodrai@linux.dev>
---
Changes in v3:
- Fix commit messages
- Link to v2: https://lore.kernel.org/r/20251104-implv2-v2-0-6dbc35f39f28@meta.com

Changes in v1:
- Split commit into 2
- Rebase on the correct branch
- Link to v1: https://lore.kernel.org/all/20251103232319.122965-1-mykyta.yatsenko5@gmail.com/
====================

Link: https://patch.msgid.link/20251104-implv2-v3-0-4772b9ae0e06@meta.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>