Re: [PATCH RESEND 1/3] tracing/syscalls: Rename variable 'nr' to 'syscall_nr'

From: Taeung Song
Date: Thu Feb 25 2016 - 12:27:09 EST

On 02/26/2016 02:09 AM, Steven Rostedt wrote:
On Thu, 25 Feb 2016 12:05:01 -0500
Steven Rostedt <rostedt@xxxxxxxxxxx> wrote:

On Fri, 26 Feb 2016 01:53:47 +0900
Taeung Song <treeze.taeung@xxxxxxxxx> wrote:

The underlying cause of this problem is not because of
the python script. This problem have relevance to tracing/syscalls
as below.

# cat
name: sys_enter_io_getevents
ID: 739
field:unsigned short common_type; offset:0;size:2;signed:0;
field:unsigned char common_flags; offset:2;size:1;signed:0;
field:unsigned char common_preempt_count; offset:3;size:1;signed:0;
field:int common_pid; offset:4;size:4;signed:1;
field:int nr; offset:8;size:4;signed:1;
field:aio_context_t ctx_id; offset:16;size:8;signed:0;
field:long min_nr; offset:24;size:8;signed:0;
field:long nr; offset:32;size:8;signed:0;
field:struct io_event * events; offset:40;size:8;signed:0;
field:struct timespec * timeout; offset:48;size:8;signed:0;

print fmt: "ctx_id: 0x%08lx, min_nr: 0x%08lx, nr: 0x%08lx, events:
0x%08lx, timeout: 0x%08lx", ((unsigned long)(REC->ctx_id)), ((unsigned
long)(REC->min_nr)), ((unsigned long)(REC->nr)), ((unsigned
long)(REC->events)), ((unsigned long)(REC->timeout))

As you see, there are duplicated variable name among fields.
So I renamed the variable name 'nr' to 'syscall_nr' to avoid this
duplication. As you know 'nr' in print_syscall_enter() mean
system call number so, I changed 'nr' to 'syscall_nr'(IMHO).

The above should have been in the change log. That makes much more

Sorry, this change log is misinterpretable.
So I'm rewriting change log for this patch.
I will resend it soon.

I'm a bit nervous about this change though. Because it is an ABI
change. Hopefully there's no tools that parse the syscall tracepoints
and expect to find a 'nr' in there.

AFIAIK, I think so but resend this modified patch.