muvarov replied on github web page:
platform/linux-generic/pktio/netmap.c
line 14
@@ -388,13 +389,22 @@ static int netmap_open(odp_pktio_t id ODP_UNUSED,
pktio_entry_t *pktio_entry,
if (pkt_nm->is_virtual) {
static unsigned mac;
+ uint32_t tid = syscall(SYS_gettid);
+
+ if ((int)tid == -1)
Comment:
.
> muvarov wrote
> man gettid says that it always passes.
>
> kernel code is also:
> pid_t __task_pid_nr_ns(struct task_struct *task, enum pid_type type,
> struct pid_namespace *ns)
> {
> pid_t nr = 0;
>
> rcu_read_lock();
> if (!ns)
> ns = task_active_pid_ns(current);
> if (likely(pid_alive(task))) {
> if (type != PIDTYPE_PID)
> task = task->group_leader;
> nr = pid_nr_ns(rcu_dereference(task->pids[type].pid), ns);
> }
> rcu_read_unlock();
>
> return nr;
> }
> EXPORT_SYMBOL(__task_pid_nr_ns);
>
> I.e. it will return init process tid 0 in worst case. So this check is not
> correct and not needed.
>
> It might be needed additional cast:
> uint32_t tid = (uint32_t)syscall(SYS_gettid) because of syscall returns pid_t.
>> muvarov wrote
>> @lumag we also use SYS_gettid() in shm and timer. I think that is not
>> subject for this PR. Just general clean up.
>>> Bill Fischofer(Bill-Fischofer-Linaro) wrote:
>>> See
>>> [here](https://stackoverflow.com/questions/21279649/getting-error-in-c-program-undefined-reference-to-gettid)
>>> for an interesting discussion of why gettid() is not used.
>>>> Dmitry Eremin-Solenikov(lumag) wrote:
>>>> @matiaselo @muvarov Hmm. I thought that there is already a Glibc wrapper.
>>>> I would prefer this as a separate function, but it is of minor priority
>>>> then.
>>>>> muvarov wrote
>>>>> it was copied from netmap source I think. gittid() will generate warning
>>>>> due to missing glibc wrapper:
>>>>> https://stackoverflow.com/questions/30680550/c-gettid-was-not-declared-in-this-scope
>>>>> Maybe something already changed...
>>>>>> Matias Elo(matiaselo) wrote:
>>>>>> What's the benefit from using gettid()? It seems like the only
>>>>>> difference is that gettid() cannot fail.
>>>>>>> Dmitry Eremin-Solenikov(lumag) wrote:
>>>>>>> Why don't you use `gettid()` function? Then you can check for its
>>>>>>> existence in `configure.ac` and provide replacement implementation.
https://github.com/Linaro/odp/pull/237#discussion_r146576250
updated_at 2017-10-24 14:22:49
