Re: [dpdk-dev] [PATCH] kni: reduce interface name size

[Michael Pfeiffer <michael.pfeiffer@tu-ilmenau.de>]

Hi Igor,
you're right, RTE_KNI_NAMESIZE == IFNAMSIZ is the intention. However,
to my understanding linux/if.h (where IFNAMSIZ is defined) is only
included when building kernel code. I thought maybe this was
intentional to keep rte_kni_common.h free of Linux kernel dependencies
(when building userland code).

In practice, it probably won't matter, as the KNI kernel module is
available for Linux only at the moment. I will therefore gladly change
this to IFNAMSIZ if you and Ferruh think this is the way to go.

Regards
Michael

On Fri, 2019-11-15 at 15:30 +0300, Igor Ryzhov wrote:
> Hi Michael,
> 
> Isn't it better to set it to IFNAMSIZ instead of 16?
> 
> Best regards,
> Igot
> 
> On Fri, Nov 15, 2019 at 2:41 PM Michael Pfeiffer <
> michael.pfeiffer@tu-ilmenau.de> wrote:
> 
> > The name in rte_kni_device_info is passed to the kernel, which
> > allows
> > interface names with at most 16 bytes (IFNAMSIZ). rte_kni_alloc
> > with a
> > longer name currently trigger a kernel BUG in alloc_netdev_mqs in
> > net/core/dev.c. Reduce RTE_KNI_NAMESIZE to prevent this situation.
> > 
> > Signed-off-by: Michael Pfeiffer <michael.pfeiffer@tu-ilmenau.de>
> > ---
> >  lib/librte_eal/linux/eal/include/rte_kni_common.h | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> > 
> > diff --git a/lib/librte_eal/linux/eal/include/rte_kni_common.h
> > b/lib/librte_eal/linux/eal/include/rte_kni_common.h
> > index 46f75a710..59339271b 100644
> > --- a/lib/librte_eal/linux/eal/include/rte_kni_common.h
> > +++ b/lib/librte_eal/linux/eal/include/rte_kni_common.h
> > @@ -18,7 +18,7 @@
> >  /**
> >   * KNI name is part of memzone name.
> >   */
> > -#define RTE_KNI_NAMESIZE 32
> > +#define RTE_KNI_NAMESIZE 16
> > 
> >  #define RTE_CACHE_LINE_MIN_SIZE 64
> > 
> > --
> > 2.20.1
> > 
> > 
-- 
Michael Pfeiffer

Technische Universität Ilmenau
Fakultät für Informatik und Automatisierung
Fachgebiet Telematik / Rechnernetze

E-Mail: michael.pfeiffer@tu-ilmenau.de
Telefon: +49 3677 69-4854
Web: https://www.tu-ilmenau.de/telematik/mitarbeiter/michael-pfeiffer/