[PATCH 11/13] tracing: export syscall_nr_to_meta function

[PATCH 11/13] tracing: export syscall_nr_to_meta function

[zhangwei(Jovi)]

Currently syscall meta table is important for kernel
syscall tracing, even mandatory, external modules may need this
meta info when perform syscall tracing(like ktap), so export it.

Instead of export variable syscalls_metadata, export function
syscall_nr_to_meta is more safe.

Signed-off-by: zhangwei(Jovi) <jovi.zhangwei@huawei.com>
---
 include/trace/syscall.h       |    2 ++
 kernel/trace/trace_syscalls.c |    3 ++-
 2 files changed, 4 insertions(+), 1 deletion(-)

diff --git a/include/trace/syscall.h b/include/trace/syscall.h
index 84bc419..3d88f63 100644
--- a/include/trace/syscall.h
+++ b/include/trace/syscall.h
@@ -31,4 +31,6 @@ struct syscall_metadata {
 	struct ftrace_event_call *exit_event;
 };

+struct syscall_metadata *syscall_nr_to_meta(int nr);
+
 #endif /* _TRACE_SYSCALL_H */
diff --git a/kernel/trace/trace_syscalls.c b/kernel/trace/trace_syscalls.c
index d24a84c..63433f9 100644
--- a/kernel/trace/trace_syscalls.c
+++ b/kernel/trace/trace_syscalls.c
@@ -102,13 +102,14 @@ find_syscall_meta(unsigned long syscall)
 	return NULL;
 }

-static struct syscall_metadata *syscall_nr_to_meta(int nr)
+struct syscall_metadata *syscall_nr_to_meta(int nr)
 {
 	if (!syscalls_metadata || nr >= NR_syscalls || nr < 0)
 		return NULL;

 	return syscalls_metadata[nr];
 }
+EXPORT_SYMBOL_GPL(syscall_nr_to_meta);

 static enum print_line_t
 print_syscall_enter(struct trace_iterator *iter, int flags,
-- 
1.7.9.7

Re: [PATCH 11/13] tracing: export syscall_nr_to_meta function

[Steven Rostedt]

On Mon, 2013-03-11 at 15:14 +0800, zhangwei(Jovi) wrote:
> Currently syscall meta table is important for kernel
> syscall tracing, even mandatory, external modules may need this
> meta info when perform syscall tracing(like ktap), so export it.
> 
> Instead of export variable syscalls_metadata, export function
> syscall_nr_to_meta is more safe.
> 
> Signed-off-by: zhangwei(Jovi) <jovi.zhangwei@huawei.com>
> ---
>  include/trace/syscall.h       |    2 ++
>  kernel/trace/trace_syscalls.c |    3 ++-
>  2 files changed, 4 insertions(+), 1 deletion(-)
> 
> diff --git a/include/trace/syscall.h b/include/trace/syscall.h
> index 84bc419..3d88f63 100644
> --- a/include/trace/syscall.h
> +++ b/include/trace/syscall.h
> @@ -31,4 +31,6 @@ struct syscall_metadata {
>  	struct ftrace_event_call *exit_event;
>  };
> 
> +struct syscall_metadata *syscall_nr_to_meta(int nr);
> +
>  #endif /* _TRACE_SYSCALL_H */
> diff --git a/kernel/trace/trace_syscalls.c b/kernel/trace/trace_syscalls.c
> index d24a84c..63433f9 100644
> --- a/kernel/trace/trace_syscalls.c
> +++ b/kernel/trace/trace_syscalls.c
> @@ -102,13 +102,14 @@ find_syscall_meta(unsigned long syscall)
>  	return NULL;
>  }
> 
> -static struct syscall_metadata *syscall_nr_to_meta(int nr)
> +struct syscall_metadata *syscall_nr_to_meta(int nr)

If you're going to make this global, then the name needs to be changed.
Perhaps call it trace_syscall_nr_to_metadata()

Anyway, this code may be totally rewritten in the near future, so
modules beware.

-- Steve

>  {
>  	if (!syscalls_metadata || nr >= NR_syscalls || nr < 0)
>  		return NULL;
> 
>  	return syscalls_metadata[nr];
>  }
> +EXPORT_SYMBOL_GPL(syscall_nr_to_meta);
> 
>  static enum print_line_t
>  print_syscall_enter(struct trace_iterator *iter, int flags,