Re: [dpdk-dev] [PATCH] net/tap: avoid using SIGIO

[Ferruh Yigit <ferruh.yigit@intel.com>]

On 8/17/2020 4:26 PM, Ferruh Yigit wrote:
> On 7/28/2020 11:48 AM, Morten Brørup wrote:
>>> From: dev [mailto:dev-bounces@dpdk.org] On Behalf Of Stephen Hemminger
>>> Sent: Monday, July 27, 2020 9:44 PM
>>>
>>> On Mon, 27 Jul 2020 15:19:32 +0200
>>> Morten Brørup <mb@smartsharesystems.com> wrote:
>>>
>>>>> From: dev [mailto:dev-bounces@dpdk.org] On Behalf Of Stephen
>>> Hemminger
>>>>> Sent: Wednesday, July 15, 2020 1:58 AM
>>>>>
>>>>> SIGIO maybe used by application, instead choose another rt-signal.
>>>>> Linux allows any signal to be used for signal based IO.
>>>>> Search for an unused signal in the available rt-signal range.
>>>>
>>>> Just an observation. Feel free to ignore at your convenience:
>>>>
>>>> The problem is the same as for SIGIO if the application sets up its
>>> own signal handler after this, and uses some hardcoded rt-signal that
>>> happens to be the one found to be free.
>>>>
>>>> Unless the application doesn't use a hardcoded rt-signal, but also
>>> searches for an unused one.
>>>>
>>>> So perhaps the "search for unused rt-signal" should be exposed as a
>>> generic support function for the application (and this driver) to use.
>>>
>>> There is no safe way to use a signal deep inside DPDK in a driver.
>>>
>>> This is not the kind of thing that should be exposed to the
>>> application.
>>>
>>> The algorithm for finding an RT signal conforms to the recommended
>>> policy on the signal(7)
>>> manual page.
>>>
>>>        programs should never refer to real-time signals using hard-
>>>        coded numbers, but instead should always refer to real-time
>>> signals
>>>        using the notation SIGRTMIN+n, and include suitable (run-time)
>>> checks
>>>        that SIGRTMIN+n does not exceed SIGRTMAX.
>>>
>>> The application should be following the proscribed policy on the man
>>> page.
>>> If it doesn't it is broken.
>>
>> Great. That fully addresses my concern.
>>
>> Acked-by: Morten Brørup <mb@smartsharesystems.com>
>>
> 
> Reviewed-by: Ferruh Yigit <ferruh.yigit@intel.com>
> 

Applied to dpdk-next-net/main, thanks.