On Thu, Aug 30, 2018 at 04:17:58PM -0400, Doug Ledford wrote: > On Thu, 2018-08-30 at 21:22 +0300, Arseny Maslennikov wrote: > > Some InfiniBand network devices have multiple ports on the same PCI > > function. This initializes the `dev_port' sysfs field of those > > network interfaces with their port number. > > > > Prior to this the kernel erroneously used the `dev_id' sysfs > > field of those network interfaces to convey the port number to userspace. > > > > The use of `dev_id' was considered correct until Linux 3.15, > > when another field, `dev_port', was defined for this particular > > purpose and `dev_id' was reserved for distinguishing stacked ifaces > > (e.g: VLANs) with the same hardware address as their parent device. > > > > Similar fixes to net/mlx4_en and many other drivers, which started > > exporting this information through `dev_id' before 3.15, were accepted > > into the kernel 4 years ago. > > See 76a066f2a2a0 (`net/mlx4_en: Expose port number through sysfs'). > > > > Signed-off-by: Arseny Maslennikov <ar@xxxxxxxxx> > > --- > > drivers/infiniband/ulp/ipoib/ipoib_main.c | 2 +- > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > diff --git a/drivers/infiniband/ulp/ipoib/ipoib_main.c b/drivers/infiniband/ulp/ipoib/ipoib_main.c > > index e3d28f9ad9c0..ba16a63ee303 100644 > > --- a/drivers/infiniband/ulp/ipoib/ipoib_main.c > > +++ b/drivers/infiniband/ulp/ipoib/ipoib_main.c > > @@ -1880,7 +1880,7 @@ static int ipoib_parent_init(struct net_device *ndev) > > sizeof(union ib_gid)); > > > > SET_NETDEV_DEV(priv->dev, priv->ca->dev.parent); > > - priv->dev->dev_id = priv->port - 1; > > + priv->dev->dev_port = priv->port - 1; > > I don't know that we can't do this. At least not yet. Expose the new > item to make us compliant with the new docs, and deprecate the old sysfs > item, but we can't just yank the old item. Existing tools/scripts might > (probably) rely on it (existing tools already special case IPoIB > interfaces and we'll need to make sure they don't special case this > element too). I'm good with keeping both items for a (probably long) while to not break things. But how exactly should we notify users of the deprecation, so they don't special case this again? A comment in the code seems too little — everyone's obviously too busy to look there and stumble upon that. A distinct notice in the doc seems too much. I can't think of another place for the deprecation notice where people would take note of it, however. Anyway: would it be OK to just restore both items and put a small note in dev_id's doc entry? If yes, I'll then send a v3.
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