[v2,00/11] Introduce kernel_clone(), kill _do_fork()

Hey everyone,

This is a follow-up to the fork-related cleanup. It's based on a brief
discussion after the initial series was merged.
Last cycle we removed copy_thread_tls() and the associated Kconfig
option for each architecture. Now we are only left with copy_thread().
Part of this work was removing the old do_fork() legacy clone()-style
calling convention in favor of the new struct kernel_clone args calling
convention.
The only remaining function callable outside of kernel/fork.c is
_do_fork(). It doesn't really follow the naming of kernel-internal
syscall helpers as Christoph righly pointed out. Switch all callers and
references to kernel_clone() and remove _do_fork() once and for all also
switching the return value for kernel_clone() from long to pid_t since
that's what we use in all other places where we're dealing with process
identifiers.

For all architectures I have done a full git rebase v5.9-rc1 -x "make
-j31". There were no built failures and the changes were fairly
mechanical.

The only helpers we have left now are kernel_thread() and kernel_clone()
where kernel_thread() just calls kernel_clone().

Thanks!
Christian

Christian Brauner (11):
  fork: introduce kernel_clone()
  h8300: switch to kernel_clone()
  ia64: switch to kernel_clone()
  m68k: switch to kernel_clone()
  nios2: switch to kernel_clone()
  sparc: switch to kernel_clone()
  x86: switch to kernel_clone()
  kprobes: switch to kernel_clone()
  kgdbts: switch to kernel_clone()
  tracing: switch to kernel_clone()
  sched: remove _do_fork()

 Documentation/trace/histogram.rst             |  4 +-
 arch/h8300/kernel/process.c                   |  2 +-
 arch/ia64/kernel/process.c                    |  4 +-
 arch/m68k/kernel/process.c                    | 10 ++--
 arch/nios2/kernel/process.c                   |  2 +-
 arch/sparc/kernel/process.c                   |  6 +--
 arch/x86/kernel/sys_ia32.c                    |  2 +-
 drivers/misc/kgdbts.c                         | 48 +++++++++----------
 include/linux/sched/task.h                    |  2 +-
 kernel/fork.c                                 | 16 +++----
 samples/kprobes/kprobe_example.c              |  6 +--
 samples/kprobes/kretprobe_example.c           |  4 +-
 .../test.d/dynevent/add_remove_kprobe.tc      |  2 +-
 .../test.d/dynevent/clear_select_events.tc    |  2 +-
 .../test.d/dynevent/generic_clear_event.tc    |  2 +-
 .../test.d/ftrace/func-filter-stacktrace.tc   |  4 +-
 .../ftrace/test.d/kprobe/add_and_remove.tc    |  2 +-
 .../ftrace/test.d/kprobe/busy_check.tc        |  2 +-
 .../ftrace/test.d/kprobe/kprobe_args.tc       |  4 +-
 .../ftrace/test.d/kprobe/kprobe_args_comm.tc  |  2 +-
 .../test.d/kprobe/kprobe_args_string.tc       |  4 +-
 .../test.d/kprobe/kprobe_args_symbol.tc       | 10 ++--
 .../ftrace/test.d/kprobe/kprobe_args_type.tc  |  2 +-
 .../ftrace/test.d/kprobe/kprobe_ftrace.tc     | 14 +++---
 .../ftrace/test.d/kprobe/kprobe_multiprobe.tc |  2 +-
 .../test.d/kprobe/kprobe_syntax_errors.tc     | 12 ++---
 .../ftrace/test.d/kprobe/kretprobe_args.tc    |  4 +-
 .../selftests/ftrace/test.d/kprobe/profile.tc |  2 +-
 28 files changed, 88 insertions(+), 88 deletions(-)


base-commit: 9123e3a74ec7b934a4a099e98af6a61c2f80bbf5

Hi,

On Wed, 19 Aug 2020 12:46:52 +0200
Christian Brauner <christian.brauner@ubuntu.com> wrote:

> The old _do_fork() helper is removed in favor of the new kernel_clone() helper.
> The latter adheres to naming conventions for kernel internal syscall helpers.

This looks good to me.

Acked-by: Masami Hiramatsu <mhiramat@kernel.org>

Thank you!

> 
> Cc: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
> Cc: Alexandre Chartre <alexandre.chartre@oracle.com>
> Cc: Jonathan Corbet <corbet@lwn.net>
> Cc: Masami Hiramatsu <mhiramat@kernel.org>
> Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
> ---
> /* v2 */
> unchanged
> ---
>  samples/kprobes/kprobe_example.c | 6 +++---
>  1 file changed, 3 insertions(+), 3 deletions(-)
> 
> diff --git a/samples/kprobes/kprobe_example.c b/samples/kprobes/kprobe_example.c
> index 240f2435ce6f..a02f53836ee1 100644
> --- a/samples/kprobes/kprobe_example.c
> +++ b/samples/kprobes/kprobe_example.c
> @@ -2,13 +2,13 @@
>  /*
>   * NOTE: This example is works on x86 and powerpc.
>   * Here's a sample kernel module showing the use of kprobes to dump a
> - * stack trace and selected registers when _do_fork() is called.
> + * stack trace and selected registers when kernel_clone() is called.
>   *
>   * For more information on theory of operation of kprobes, see
>   * Documentation/staging/kprobes.rst
>   *
>   * You will see the trace data in /var/log/messages and on the console
> - * whenever _do_fork() is invoked to create a new process.
> + * whenever kernel_clone() is invoked to create a new process.
>   */
>  
>  #include <linux/kernel.h>
> @@ -16,7 +16,7 @@
>  #include <linux/kprobes.h>
>  
>  #define MAX_SYMBOL_LEN	64
> -static char symbol[MAX_SYMBOL_LEN] = "_do_fork";
> +static char symbol[MAX_SYMBOL_LEN] = "kernel_clone";
>  module_param_string(symbol, symbol, sizeof(symbol), 0644);
>  
>  /* For each probe you need to allocate a kprobe structure */
> -- 
> 2.28.0
>