On Tue, 03 Sep 2013 19:50:28 +0900, Masami Hiramatsu wrote:
> (2013/09/03 14:44), Namhyung Kim wrote:
>> From: Namhyung Kim <[email protected]>
>>
>> Fetching from user space should be done in a non-atomic context. So
>> use a per-cpu buffer and copy its content to the ring buffer
>> atomically. Note that we can migrate during accessing user memory
>> thus use a per-cpu mutex to protect concurrent accesses.
>>
>> This is needed since we'll be able to fetch args from an user memory
>> which can be swapped out. Before that uprobes could fetch args from
>> registers only which saved in a kernel space.
>>
>> While at it, use __get_data_size() and store_trace_args() to reduce
>> code duplication.
[SNIP]
>> + size = esize + tu->p.size + dsize;
>> event = trace_current_buffer_lock_reserve(&buffer, call->event.type,
>> - size + tu->p.size, 0, 0);
>> - if (!event)
>> + size, 0, 0);
>> + if (!event) {
>> + mutex_unlock(mutex);
>> return;
>
> Just for a maintenance reason, I personally like to use "goto" in this case
> to fold up the mutex_unlock. :)
>
> Other parts are good for me.
>
> Reviewed-by: Masami Hiramatsu <[email protected]>
Thank you for review!
I'll change it as you said and fix atomic_dec bug that Jovi found.
Thanks,
Namhyung
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