Re: [dpdk-dev] [PATCH v2 10/10] kni: add API to set link status on kernel interface

[Stephen Hemminger <stephen@networkplumber.org>]

On Mon, 3 Sep 2018 21:47:22 -0300
Dan Gora <dg@adax.com> wrote:

> Hi All,
> 
> One other problem with using the sysfs method to change the link state
> rather than this ioctl method.  The sysfs/netdev method to change the
> carrier was only introduced in kernel 3.9.  For older kernels, we
> would just be out of luck.  The ioctl method will work with any kernel
> version (2.6+).  It's not clear if this is a problem for DPDK apps or
> not.
> 
> thanks
> dan
> 
> 
> On Thu, Aug 30, 2018 at 7:11 PM, Dan Gora <dg@adax.com> wrote:
> > On Thu, Aug 30, 2018 at 7:09 PM, Stephen Hemminger
> > <stephen@networkplumber.org> wrote:  
> >> On Thu, 30 Aug 2018 18:41:14 -0300
> >> Dan Gora <dg@adax.com> wrote:
> >>  
> >>> On the other hand, the "write to /sys" method is a bit more simple and
> >>> confines the changes to the user space library.  If we're confident
> >>> that the /sys ABI is stable and not going to be changed going forward
> >>> it seems like a valid alternative.  
> >>
> >> See Documentation/ABI/testing/sysfs-class-net  
> >
> > yeah, but it's in the 'testing' directory :)
> >
> > From Documentation/ABI/README:
> >
> > testing/
> >
> > This directory documents interfaces that are felt to be stable,
> > as the main development of this interface has been completed.
> > The interface can be changed to add new features, but the
> > current interface will not break by doing this, unless grave
> > errors or security problems are found in them.  Userspace
> > programs can start to rely on these interfaces, but they must be
> > aware of changes that can occur before these interfaces move to
> > be marked stable.  Programs that use these interfaces are
> > strongly encouraged to add their name to the description of
> > these interfaces, so that the kernel developers can easily
> > notify them if any changes occur (see the description of the
> > layout of the files below for details on how to do this.)
> >
> > Like I said, I'm ok with using this if that's what everyone wants to do.
> >
> > d  
> 
> 
> 

Linux 3.9 is no longer supported. Currently, upstream Linux kernel is supported
from 3.16 on. If someone is on a kernel that old, they aren't going to get
any security fixes.