From mboxrd@z Thu Jan 1 00:00:00 1970 From: Matt Domsch Date: Mon, 29 Nov 2010 03:29:09 +0000 Subject: net device renaming 2-step, IFNAMSIZ limit Message-Id: <20101129032908.GA29904@auslistsprd01.us.dell.com> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: linux-hotplug@vger.kernel.org Once again, IFNAMSIZ bites me. I see this in the udev debug logs when using biosdevname (which I finally got working with SR-IOV devices tonight): renamed network interface eth60 to eth60-pci2#0_60 renamed network interface eth60-pci2#0_60 to pci2#0_60 So, it worked, however, note that the rename happens in 2 steps, the middle step of which uses a name that's dangerously close to IFNAMSIZ, in fact it is 15 chars there. In my testing, I'm doing: modprobe ixgbe max_vfsc which generates ethN..(N+127) interfaces (yes, 128 new interfaces) on this dual-port card. Combine that with the longer names that biosdevname is suggesting: pciNN#PP_VVV which is itself already 12 chars if all the fields are used to their maximum length, and the concatenation of - is way past IFNAMSIZ. I need a solution in which the intermediate name doesn't exceed 15 characters, and is guaranteed to be unique, as there may be lots of udev instances running in parallel trying to do the same thing. Ideas? (note, vconfig can create VLANs for interfaces, which needs another 5 characters appended on the end, but that's for another day). Thanks, Matt -- Matt Domsch Technology Strategist Dell | Office of the CTO