Hi Jiri,
On Fri, 3 Jan 2014 14:24:25 +0100, Jiri Olsa wrote:
> On Thu, Dec 19, 2013 at 06:34:23PM +0900, Namhyung Kim wrote:
>> From: Namhyung Kim <namhyung....@lge.com>
>>
>> The trace_seq->state is for tracking errors during the use of
>> trace_seq APIs and getting rid of die() in it.
>>
>> Signed-off-by: Namhyung Kim <namhy...@kernel.org>
>> ---
>> tools/lib/traceevent/event-parse.h | 7 +++++++
>> tools/lib/traceevent/trace-seq.c | 41
>> ++++++++++++++++++++++++++++++++++----
>> 2 files changed, 44 insertions(+), 4 deletions(-)
>>
>> diff --git a/tools/lib/traceevent/event-parse.h
>> b/tools/lib/traceevent/event-parse.h
>> index cf5db9013f2c..3c890cb28db7 100644
>> --- a/tools/lib/traceevent/event-parse.h
>> +++ b/tools/lib/traceevent/event-parse.h
>> @@ -58,6 +58,12 @@ struct pevent_record {
>> #endif
>> };
>>
>> +enum trace_seq_fail {
>> + TRACE_SEQ__GOOD,
>> + TRACE_SEQ__BUFFER_POISONED,
>> + TRACE_SEQ__MEM_ALLOC_FAILED,
>> +};
>> +
>> /*
>> * Trace sequences are used to allow a function to call several other
>> functions
>> * to create a string of data to use (up to a max of PAGE_SIZE).
>> @@ -68,6 +74,7 @@ struct trace_seq {
>> unsigned int buffer_size;
>> unsigned int len;
>> unsigned int readpos;
>> + enum trace_seq_fail state;
>> };
>>
>> void trace_seq_init(struct trace_seq *s);
>> diff --git a/tools/lib/traceevent/trace-seq.c
>> b/tools/lib/traceevent/trace-seq.c
>> index d7f2e68bc5b9..976ad2a146b3 100644
>> --- a/tools/lib/traceevent/trace-seq.c
>> +++ b/tools/lib/traceevent/trace-seq.c
>> @@ -32,8 +32,8 @@
>> #define TRACE_SEQ_POISON ((void *)0xdeadbeef)
>> #define TRACE_SEQ_CHECK(s) \
>> do {
>> \
>> - if ((s)->buffer == TRACE_SEQ_POISON) \
>> - die("Usage of trace_seq after it was destroyed"); \
>> + if ((s)->buffer == TRACE_SEQ_POISON) \
>> + (s)->state = TRACE_SEQ__BUFFER_POISONED; \
>
> So unless we use trace_seq_do_printf we dont have any
> notification that this went wrong..?
Right.
>
> How about use some sort of WARN_ONCE any time the state
> is set != GOOD ?
I'm not sure what's the right thing to do for that case. Printing a
warning message might disturb user's output since it can be in a middle
of some (other) processing and she doesn't want to print anything during
the processing for some reason.
I just thought that it's not so important to print message so keeps the
error internally until it gets printed. But I can be wrong as usual...
Thanks,
Namhyung
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