Pre-3.15 userspace had trouble distinguishing different ports of a NIC on a single PCI bus/device/function. To solve this, a sysfs field `dev_port' was introduced quite a while ago (commit v3.14-rc3-739-g3f85944fe207), and some relevant device drivers were fixed to use it, but not in case of IPoIB.
The convention for some reason never got documented in the kernel, but was immediately adopted by userspace (notably udev[1][2], biosdevname[3]) 1/3 documents the sysfs field — that's why I'm CC-ing netdev. This series was tested on and applies to 4.19-rc2. [1] https://lists.freedesktop.org/archives/systemd-devel/2014-June/020788.html [2] https://lists.freedesktop.org/archives/systemd-devel/2014-July/020804.html [3] https://github.com/CloudAutomationNTools/biosdevname/blob/c795d51dd93a5309652f0d635f12a3ecfabfaa72/src/eths.c#L38 v1->v2: replace a line instead of inserting and then removing. v2->v3: restore both attributes, output a notice of deprecation to kmsg. v3->v4: style adjustments, join the deprecation notice to single line. Arseny Maslennikov (3): Documentation/ABI: document /sys/class/net/*/dev_port IB/ipoib: Use dev_port to expose network interface port numbers IB/ipoib: Log sysfs 'dev_id' accesses from userspace Documentation/ABI/testing/sysfs-class-net | 18 +++++++++++++ drivers/infiniband/ulp/ipoib/ipoib_main.c | 33 +++++++++++++++++++++++ 2 files changed, 51 insertions(+) -- 2.19.0.rc2
